Physics Optics Bench

Physics Available PhD Projects

The Department of Physics offers the following postgraduate research degrees:

Nanoscience Division

David Birch, Photophysics

Carbon nanoparticle metrology
There is an international need for improved measurement methods with which to characterize nanoparticles and establish standards for them (1) Of particular note is the present lack of clarity concerning the potential toxicology of carbon nanoparticles in the 1-10 nm range that traverse cell membranes with ease, and which are ubiquitous in combustion products of vehicle emissions and power stations. Measurement of vehicle emissions has recently become very topical and the need for reliable measurement methods is expected to become increasingly important in the future. This project aims to measure carbon nanoparticle size using techniques that were recently developed by the Photophysics Group for silica (2) and which are based on the fluorescence anisotropy decay of a dye (3) attached to the nanoparticle as it undergoes Brownian rotation. 

1. T. Linsinger, G. Roebben, D. Gilliland, L. Calzolai, F. Rossi, P. Gibson, C. Klein, pdf icon Requirements on measurements for the implementation of the European Commission definition of the term 'nanomaterial, EUR 25404 EN. Luxembourg (Luxembourg): Publications Office of the European Union; 2012. JRC73260

2. P. Yip, J. Karolin and D. J. S. Birch. Fluorescence anisotropy metrology of electrostatically and covalently labelled silica nanoparticles. Meas. Sci. Technol. 23, 084003, 2012.

3. D J S Birch, Y Chen and O J Rolinski. Fluorescence in “Biological and Medical Photonics, Spectroscopy and Microscopy.” Ed D L Andrews. Vol 4 “Photonics.” Wiley. Ch.1. 1-58, 2015.

Yu Chen, Photophysics

Nanoscale energy transfer and applications
Energy transfer is one of the most fundamental processes on the molecular scale, governing light-harvesting in biological systems and energy conversion in electronic devices such as organic solar cells or light-emitting diodes. Noble metal nanoparticles have unique properties different from their bulk counterparts and can have significant effects in energy transfer processes. This project aims to investigate the energy transfer between fluorescence dyes and metal nanostructures and to develop novel material systems and devices for applications in biosensors, nanoscale light sources, nanomedicine and solar cells. This is a multidisciplinary project, involving state-of-the-art nanomaterial synthesis, optical and electron spectroscopy and microscopy at the interface of nanotechnology and life science.

The student will be based in Photophysics Group in the Department of Physics, with access to outstanding laboratories and facilities, including the Centre of Molecular Nanometrology. This centre was launched jointly by the Department of Physics and the Department of Pure and Applied Chemistry with £2M investment in 2005 and has been awarded a further £5M under the EPSRC Science and Innovation Initiative. The centre has strong collaborations with other research groups, industry and biomedical practitioners.

1. Y. Zhang, D. J. S. Birch and Y. Chen, "Energy transfer between DAPI and gold nanoparticles under two-photon excitation", App. Phys. Lett., 99, 103701 (2011)
2. P. Gu, D.J.S. Birch and Y. Chen, "Dye-dope polystyrene-coated gold nanorods: towards wavelength tuneable SPASER", Methods Appl. Fluoresc. 2 024004 (2014)
Nanotechnology of gold nanoparticles for biomedical imaging and sensing
Gold nanoparticles have great potential in biomedical applications because of their biocompatibility, accessibility, chemical functionality and unique optical properties arising from surface plasmon resonance. This project aims to develop gold nanoparticle based nanoprobes for molecular biomarker imaging at single cell level. Nanoprobes capable of multiplexible biomarker detecting and specific cell targeting will be synthesized. We will utilize both steady state and dynamic fluorescence spectroscopy and microscopy to investigate the functionality of nanoprobes in solution phase and cell culture. The potential application for early cancer diagnosis and prognosis will be assessed. 

The student will be based in Photophysics Group in the Department of Physics, with access to outstanding laboratories and facilities, including the Centre of Molecular Nanometrology. This centre was launched jointly by the Department of Physics and the Department of Pure and Applied Chemistry with £2M investment in 2005 and has been awarded a further £5M under the EPSRC Science and Innovation Initiative. The centre has strong collaborations with other research groups, industry and biomedical practitioners.

1. Y. Zhang, G. Wei, J. Yu, D. J. S. Birch and Y. Chen, "Surface plasmon enhanced energy transfer between gold nanorods and fluorophores: application to endosytosis study and RNA detection", Faraday Discuss. DOI: 10.1039/C4FD00199k. 
2. Y. Zhang, J. Yu, D. J. S. Birch and Y. Chen, "Gold nanorods for fluorescence lifetime imaging in biology", Journal of Biomedical Optics, 15, 020504 (2010).

Benjamin HourahineSSD

Extreme scale computational simulation techniques
Current computational approaches can treat systems with up to around 1E11 degrees of freedom using large parallel computational resources. This translates into atomistic simulations limited to a few micrometers in size, astrophysical simulations that require million solar mass fictitious particles to trace cosmological evolution, or weather simulations where features on the scale of the whole of the Clyde valley is represented only as a single voxel. This project aims to develop and apply strongly multiscale methods to instead access simulations on the scale of 1E20 degrees of freedom, this will be achieved through the use of self-similarity within the framework of renormalisation group methods.
Understanding Electron Microscopy Images
Electron Channelling Contrast Imaging (ECCI) and Electron Back Scatter Diffraction (EBSD) are efficient and powerful methods to characterise a wide range of materials and obtain information about their microstructure and structural defects. This enables, for example, rapid and statistically significant measurements of dislocation types and densities in semiconductors, but for more complex defects it can become more challenging to interpret the measured images. This project will develop approaches to understand these cases, based on a combination of multiscale simulation of the strain in materials together with simulation of inelastic electron channelling.
Information in nano-plasmonics
Building on recent theoretical developments to obtain the fundamental optical modes of nanostructures, this project aims to study the information carrying and processessing capabilities of systems of nanoparticles interacting with both classical and quantum light. One aim is to quantify the inverse problem of light scattering, i.e. how much information is needed and how difficult is it to reconstruct the structure and properties of nanoparticles from optical measurements?

Neil Hunt, UCP

Ultrafast 2D-IR spectroscopy of protein-drug interactions

Ultrafast 2D-IR spectroscopy has developed over the last decade into a powerful new tool for investigating the structure and dynamics of proteins and enzymes.

In this project we seek to build on recent work in our group looking at the way in which dynamic motions of biomolecules relate to their function by extending this to encompass drug-protein binding.

The successful applicant will join a multidisciplinary team that includes physicists, chemists and biologists and will apply 2D-IR spectroscopy to proteins and their mutants as well as to drugs with purpose-built probe groups in order to fully understand the intimate contacts between the two parts of the system.

The project is open to applicants with interests in physical chemistry or molecular physics. No experience of chemistry or biology is required but would be an advantage. Willingness to work as part of a large team is essential.

The role of dynamics in the biological structure function relationship
The relationship between structure and function of biological molecules (proteins and enzymes) is well-established. However little is known about the role of fast dynamics associated with the vibrations of the protein backbone or the motion of solvating water molecules in influencing this functionality.

This project seeks to combine ultrafast 2D-IR spectroscopy with structural biology in order to answer this question. In particular we will seek to examine the intermolecular interactions that are fundamental to biology: protein-ligand binding and protein-DNA binding. By comparing ultrafast spectroscopy results with established structural tools such as crystallography and NMR alongside molecular dynamics simulations, we will seek to add the information on dynamics that 'animates' static protein structures and begin to understand the role of dynamic atomic and molecular processes in biology.

The project is open to applicants with interests in physical chemistry or molecular physics. No experience of chemistry or biology is required but would be an advantage. Willingness to work as part of a collaborative team is essential.
Ultrafast spectroscopy of next-generation bio-inspired materials for Hydrogen-production

The hydrogenase enzymes are biological molecules which can catalyse to production of hydrogen gas from protons with impressive efficiency. These enzymes have thus inspired considerable research efforts aimed at making synthetic replicas of the enzyme active site for use in the technological sunlight-driven generation of this important next-generation fuel source.

This project will form part of a collaborative effort seeking to use ultrafast spectroscopy (pump-probe and 2D-IR) to understand the photochemistry and structural dynamics of these synthetic systems. The project is open to applicants with interests in physical chemistry or molecular physics. No experience of chemistry or biology is required but would be an advantage. Willingness to work as part of a collaborative team is essential.

Gail McConnell & Erling Riis, Biophotonics & Photonics

A new super-resolution optical microscopy method for live cell imaging

A PhD position (fully funded for UK/EU students only) is available at the University of Strathclyde in the Centre for Biophotonics and the Department of Physics. The successful candidate will develop and use a new super-resolution optical microscope to obtain very high spatial resolution images of fluorescently labelled live cells.

The PhD project will focus on:

  • Design and construction of the optical microscope
  • Use of laser and LED sources for excitation of fluorescence
  • Application of cutting-edge sensor technology for obtaining time-resolved images
  • Learning specimen preparation techniques, including fluorescence labelling and cell culture
  • Analysis of the data and making 3D and 4D image reconstructions of cells and tissues
  • Writing papers and communicating outcomes of research at national and international conferences

The project will offer cutting-edge research training in optics and biophotonics, as well as postgraduate teaching and training as part of the SULSA (Scottish Universities Life Science Alliance) partnership through the Graduate School. Financial support will be made available for presentation of results at national and international conferences.

The successful applicant will have dedication and enthusiasm for experimental research, and will have good communication skills.

Please send enquiries to Prof. Gail McConnell

Robert Martin, Carol Trager-Cowan and Benjamin Hourahine, SSD

Nanoanalysis of semiconductors and devices built from III-nitrides

This project will investigate technologically important GaN-based semiconductor materials. Such materials underpin highly successful and growing technologies, such as LED lighting and power transistors, and also have great potential in developing technologies, such as UV emitters and solar energy converters, but deeper understanding of the materials is needed to ensure progress. Advanced and developing scanning electron microscope based techniques such as electron channelling contrast imaging, cathodoluminescence and electron beam induced conductivity, will be used to analyse the structural, optical and electrical properties of state-of-the-art III-nitride semiconductor structures down to the nanometer scale. The experimental data acquired will be combined via software tools developed in the group to provide as much information as possible on the material and on the performance that can be delivered in subsequent devices. Experiments will be guided and data interpreted through use of theoretical simulations and machine vision tools. New instrument development involving collaboration with academic and industrial partners is further expanding our materials’ characterisation capabilities. The GaN-based structures will be provided from epitaxy specialists at collaborating groups at the Universities of Cambridge, Sheffield, Bath, Cork and Nottingham and from industry.

Brian Patton, Nanobiophotonics

Nanodiamond as an Optically Robust Fluorophore for Targeted Imaging of Neural Structures

One of the key scientific challenges of the 21st century is to better understand the principles that allow a collection of neural cells to work as a fully functioning brain. The complexity of neurobiology, along with the range of possible parameters to be investigated means that new techniques are embraced and quickly incorporated.

Nanodiamond (ND) offers many advantages as a fluorescent label for biological applications. Its biocompatibility, potential sensitivity to electric and magnetic fields, lack of photobleaching and the possibility of targetting specific neural structures are all of particular interest to researchers in neurophysiology. This PhD project aims to develop a comprehensive suite of tools and techniques that will enable superresolution imaging of NDs in brain tissue. By utilising Stimulated Emission Depletion (STED) microscopy, in conjunction with adaptive optics, it will be possible to image ND tens of microns into tissue with a resolution of 50nm. Achieving this resolution will allow imaging of synapic sites, the anatomical features where signals are passed from one neuron to another, thereby allowing a better understanding of the propagation of information through the brain. It follows that a key goal for the student will be to obtain a better understanding of how best to functionalise and bind ND to sites of interest, such as synapses, within brain, and other, tissue.

In order to allow both superresolution imaging, and the later extension to electric and magnetic field sensing, it will also be important to understand how nitrogen-vacancy (NV) centres in the ND are affected by the surface chemistry required for functionalisation, as this may influence the optical activity of the NV centres. Furthermore, intrinsic strain fields in the ND can influence both the formation and optical activity of NV centres within a ND and will also require investigation during the course of the studentship.

In the context of biological imaging, the effects of strain can also be beneficial. Strain also leads to a splitting in the optically detected magnetic resonance of NV centres that could be used as a fingerprint for individual centres. This would allow initial, high-resolution imaging, localisation and characterisation using STED followed by longer term, less damaging imaging using conventional methods such as confocal or wide-field imaging.

Funding Notes

This position is funded through the Diamond Science and Technology Centre for Doctoral Training, headed by the University of Warwick.

The successful applicant will be required to undertake the MSc taught component at Warwick and then two associated mini-projects at the Universities of Newcastle and Oxford. This approach to PhD training offers great benefits: sutdents get to work at two partner universities and can be part of a great network being taught by experts from 8 different universities which they can tap into in future years

Super-resolution imaging of biological organisms: seeing below the classical limits

One of the key scientific challenges of the 21st century is to better understand the principles that allow a collection of neural cells to work as a fully functioning brain. The complexity of neurobiology, along with the range of possible parameters to be investigated means that new techniques are embraced and quickly incorporated.

A key aspect of the group’s research involves imaging small particles of diamond known as nanodiamond (ND). This material offers many advantages as a fluorescent label for biological applications. Its biocompatibility, potential sensitivity to electric and magnetic fields, lack of photobleaching and the possibility of targetting specific neural structures are all of particular interest to researchers in neurophysiology. This PhD project aims to develop a comprehensive suite of tools and techniques that will enable superresolution imaging of NDs in living tissue, with a particular emphasis on imaging neurons. By utilising Stimulated Emission Depletion (STED) microscopy, in conjunction with adaptive optics, it will be possible to image ND tens of microns into tissue with a resolution of 50nm. Achieving this resolution will allow imaging of synaptic sites, the anatomical features where signals are passed from one neuron to another, thereby allowing a better understanding of the propagation of information through the brain.

Successful candidates will gain a wide range of experience in skills such as: Optical hardware design and alignment, developing software for hardware control and data processing, labelling samples for imaging and collaboration with colleagues in the biological sciences to ensure our research also enables new biological science.

Funding Notes

Project will be funded by a Strathclyde University studentship - eligibility for a full scholarship is limited to EU citizens

References

Solid Immersion Facilitates Fluorescence Microscopy with Nanometer Resolution and Sub-Ångström Emitter Localization 
Dominik Wildanger, Brian R. Patton, Heiko Schill, Luca Marseglia, J. P. Hadden, Sebastian Knauer, Andreas Schönle, John G. Rarity, Jeremy L. O’Brien, Stefan W. Hell, and Jason M. Smith, Advanced Materials 24, OP309-OP313 (2012) 
doi: 10.1002/adma.201203033

Adaptive optics correction of specimen-induced aberrations in single-molecule switching microscopy 
D Burke, B Patton, F Huang, J Bewersdorf, MJ Booth 
Optica 2 (2), 177-185, (2015) 
doi: 10.1364/OPTICA.2.000177 

Is phase-mask alignment aberrating your STED microscope? 
BR Patton, D Burke, R Vrees, MJ Booth 
Methods and Applications in Fluorescence 3 (2), 024002 (2015) 
doi:10.1088/2050-6120/3/2/024002

Aberrations and adaptive optics in super-resolution microscopy 
M Booth, D Andrade, D Burke, M Patton, Brian and Zurauskas Mantas 
Microscopy 64 (5), (2015) 
doi: 10.1093/jmicro/dfv033

Three-dimensional STED microscopy of aberrating tissue using dual adaptive optics 
Brian R. Patton, Daniel Burke, David Owald, Travis J. Gould, Joerg Bewersdorf, and Martin J. Booth 
Optics Express 24 (8), 8862-8876 (2016) 
doi: 10.1364/OE.24.008862

Carol Trager-Cowan, SSD

3-D nanoscale structural analysis in the scanning electron microscope through application of direct electron detectors
The PhD student will join our multidisciplinary research team developing and applying novel scanning electron microscopy techniques to the understanding of materials. 

See http://gan-sem.phys.strath.ac.uk/ for some of our current research activities. 

This project is focussed on developing and applying next generation detectors for the scanning electron microscopy techniques of electron backscatter diffraction (EBSD) and electron channelling contrast imaging (ECCI). 

This joint project between The University of Strathclyde, Glasgow and the National Physical Laboratory, Teddington promises to open up a whole new research area in non-destructive three dimensional texture, strain and defect mapping in solid-state materials. Such information is invaluable for the optimisation of new materials ranging from steels for the automotive industry; to titanium based alloys for aerospace applications; to semiconductor thin films for use in the solid state lighting and electronics industries. 

The student will work together with researchers at The University of Strathclyde, the National Physical Laboratory, the University of Glasgow and other research collaborators from both academia and industry. The project is to interface a direct electron detector to a dual beam (electron and ion beam) instrument for three-dimensional analysis of the structural properties of materials via the novel scanning electron microscopy techniques of electron backscatter diffraction (EBSD) and electron channelling contrast imaging (ECCI). The use of such a detector will dramatically improve speed and performance of such measurements. Materials problems to be addressed include the optimisation of ion implantation in semiconductors – this will also take advantage of the new electron probe microanalyser to be installed within the new Technology and Innovation Centre at the University of Strathclyde, and the optimisation of nitride based electronic devices. 

The student will be based at the University of Strathclyde but will have the opportunity to spend substantial time at the National Physical Laboratory. 

To discuss the project please contact Dr Carol Trager-Cowan.

References

1. S Vespucci, A Winkelmann, G Naresh-Kumar, KP Mingard, D Maneuski, PR Edwards, AP Day, V O'Shea and C Trager-Cowan, 'Digital direct electron imaging of energy-filtered electron backscatter diffraction patterns' Phys. Rev. B. Vol 92, 205301 (2015). 
G. Naresh-Kumar, C Mauder, K R Wang, S Kraeusel, J Bruckbauer, P R Edwards, B Hourahine, H Kalisch, A Vescan, C Giesen, M Heuken, A Trampert, A P Day, and C Trager-Cowan, 'Electron channeling contrast imaging studies of non-polar nitrides using a scanning electron microscope', Appl. Phys. Lett. Vol. 102, 142103 (2013).
 2. G Naresh-Kumar, B Hourahine, P R Edwards, A P Day, A Winkelmann, A J Wilkinson, P J Parbrook, G England and C Trager-Cowan, "Rapid nondestructive analysis of threading dislocations in wurtzite materials using the scanning electron microscope", Phys. Rev. Lett. Vol. 108 135503 (2012). 
3. C Trager-Cowan, F Sweeney, A Winkelmann, A J Wilkinson, PW Trimby, A P Day, A Gholinia, N-H Schmidt, P J Parbrook and I M Watson I M, “Characterisation of nitride thin films by electron backscatter diffraction and electron channelling contrast imaging”, invited paper Materials Science and Technology (Special Edition on Advances in EBSD) Vol. 22 1352 (2006). 
4. C Trager-Cowan, F Sweeney, P Trimby, A Day, A Gholinia, N-H Schmidt, P J Parbrook, A J Wilkinson and I M Watson “Electron backscatter diffraction and electron channelling contrast imaging of tilt and dislocations in nitride thin films”, Phys. Rev. B Vol. 75, 085301 (2007). 
5. A Winkelmann, C Trager-Cowan, F Sweeney, A P Day and P J Parbrook, “Many-beam dynamical simulation of electron backscatter diffraction patterns”, Ultramicroscopy Vol. 107 414 (2007). 
6. C Trager-Cowan, F Sweeney, A J Wilkinson, I M Watson, P G Middleton, K P O’Donnell, D Zubia, S D Hersee, S Einfeldt and D Hommel, “Determination of the structural and luminescence properties of nitrides using electron backscattered diffraction and photo- and cathodoluminescence”, phys. stat. sol. (c) Vol. 0, 532 (2002). 
7. S Pereira, M R Correia, E Pereira, K P O'Donnell, C Trager-Cowan, F Sweeney and E Alves, “Compositional pulling effects in InxGa1-x N/GaN layers: A combined depth-resolved cathodoluminescence and Rutherford backscattering/channeling study”, Phys. Rev. B, Vol. 64, 205311 (2001).

Optics Division

Thorsten AckemannPhotonics

Dynamics and rogue waves in injection-locked broad-area lasers
Semiconductor lasers are high performance devices which are an enabling technology for the modern information society. Their complex dynamics are of strong scientific interest and emerging technological significance. Evidence of “rogue pulses” were found in injection-locked semiconductor lasers in spatial single-mode operation [PRL 107, 053901 (2011)] contributing to the rapidly developing field of extreme events [J Opt B 18, 063001 (2016)]. Recent theoretical work at Strathclyde indicates a new mechanism for rogue waves in spatially extended, injected laser systems [PRL 116, 043903 (2016)]. This project is aimed at promoting the understanding of the complex dynamics of spatially extended, multi-mode systems with an experimental focus. The complex dynamics of injection-locked broad-area vertical-cavity semiconductor lasers (VCSELs) and broad-area edge-emitting semiconductor lasers will be analysed via complexity measures [Opt Exp 22, 1713 (2014)] and contrasted. Both systems will be explored for evidence of coupling between temporal and spatial dynamics and the potential for spatio-temporal rogue waves. 

The PhD project will involve:  
  • design and construction of computer controlled nonlinear laser systems with automated data collection
  • application of cutting-edge, multi-GHz bandwidth, real-time output power time series measurements
  • learning and further researching nonlinear dynamics and high-end data analysis, including complexity measures
  • developing big data handling capabilities
  • writing papers and communicating outcomes of research at national and international conferences
Macquarie University (Sydney, Australia) and the University of Strathclyde (Glasgow, UK) are inviting applications from EU citizens for a Joint PhD in the area of Lasers and Nonlinear dynamics. A Joint PhD enables students to simultaneously enrol in a doctoral degree at two universities and submit a single thesis for joint recognition. Students will be guided by supervisors from each university and spend 20 months on campus at Macquarie University and 22 months at University of Strathclyde, benefitting from the resources and expertise of each partner and the international research collaboration between the groups. One thesis is submitted for joint examination, and upon meeting the requirements of both institutions, a single PhD testamur is issued bearing the crests of both universities. An eligible applicant will need to be successful in a competitive scholarship scheme and will be provided with stipend plus tuition fees, if successful. The applicant must submit an application for admission and a scholarship to both institutions. 
Suitable applicants for this PhD position will have achieved a Master Degree by research or 2-year Master by coursework with a major research component in experimental physics (or related discipline with equivalence) at First Class/High Distinction level or equivalent. Applicants with other research-focused qualifications or a combination of qualifications and relevant research experience (eg, a record of publications) may also be considered. 
The candidate needs to apply simultaneously to both institutions. 

Please contact Professor Deborah Kane (deb.kane@mq.edu.au) and Professor Thorsten Ackemann (thorsten.ackemann@strath.ac.uk) before starting the formal application process. The deadline might be flexible. 
References 
1. Review article: T. Ackemann, W. J. Firth, G.-L. Oppo. Fundamentals and Applications of Spatial Dissipative Solitons in Photonic Devices. Adv. Atom., Mol., Opt. Phys. 57, 323 (2009) 
2. Y. Tanguy, T. Ackemann, W. J. Firth, and R. Jaeger. Realization of a semiconductor-based cavity soliton-laser. Phys. Rev. Lett. 100, 013907 (2008). 
3. C. J. Gibson, A. M. Yao, and G.-L. Oppo, Optical Rogue Waves in Vortex Turbulence, Phys. Rev. Lett. 116, 043903 (2016) 
4. J. P. Toomey and D. M. Kane, Mapping the dynamic complexity of a semiconductor laser with optical feedback using permutation entropy, Opt. Exp. 22, 1713 (2014)
Dynamics in spatially extended semiconductor lasers
The project is aimed at promoting the understanding of the complex nonlinear dynamics of broad-area semiconductor lasers with fundamental and applied aspects. It will look at the synchronization dynamics between different broad-area lasers and between different patches or solitons within the same laser. Data analysis will use methods of complexity science. The project will lead to a joint PhD degree with Macquarie University, Sydney, (18 month Strathclyde, 18 month Macquarie) and demands the simultaneous acceptance at Macquarie (first class Masters degree or equivalent).

Andrew Daley, CNQO

Quantum Simulation of ultracold atoms and molecules

Recent experiments with ultracold atoms have made it possible to control and measure many-particle dynamics on a microscopic level.

This opens new opportunities to explore fundamental questions, including under which conditions a system "thermalises", or reaches thermal equilibrium; how quantum systems react after sudden changes in the system parameters; and how entanglement develops in quantum many-particle systems during out-of-equilibrium dynamics.

The aim of this project is to explore new paradigms of such dynamics theoretically, using analytical techniques and state-of-the art numerical methods, and set part of a roadmap for future experiments in this field.

Engineering entanglement in many-atom states
Recent developments in experiments with ultracold atoms have made it possible to control and measure many-particle dynamics on a microscopic level. These experiments open new opportunities to answer fundamental questions, and also to harness quantum states for important future applications.

The aim of this project is to develop new methods to produce and characterise entangled states of many atoms in 3D optical lattices using both dissipative and coherent processes. This involves understanding fundamental properties of many-particle dynamics through analytical and numerical techniques, including recently developed matrix product operator methods and time-dependent density matrix renormalisation group techniques. Our goals are to develop new fundamental understanding of these dynamics, and to devise new protocols that can be used to precisely identify characteristic properties of many-body physics in experiments (e.g., locating quantum phase transition points), and to engineer states that can enhance precision measurement (e.g., in next-generation atomic clocks).

These theoretical studies are directly related to ongoing experiments, including work being performed in the photonics groups at the University of Strathclyde.

The Optics Division will be a focal point of the EPSRC Quantum Technology Hubs, and has received significant funding from the recent call to expand our multi-disciplinary research in both experimental and theoretical fields. 

We also offer postgraduate teaching and training as part of the SUPA (Scottish Universities Physics Alliance) and IMPP (International Max Planck Partnership). Financial support is available for collaborative work and for presentation of results at national and international conferences. Applicants should have an excellent first degree in Physics, Engineering, or a related discipline.

Paul Griffin, Photonics

Detection of Magnetic Fields at the Lowest Limit
Magnetism is one of the fundamental and ubiquitous forces of nature, appearing across the range of sciences, from atomic physics to biology. Perhaps the simplest model for magnetism is of a single electron attached to a positive nucleus. This model allows for development of a rigorous and thorough quantum mechanical description of the interactions between the energy of the electron and the magnetic field. However, far from being an abstract theoretical system, this model is fully realised in the alkali atoms, and recent developments in atomic spectroscopy have opened the way to use this paradigmatic system to precisely interrogate environmental fields at the quantum limit.

A new, fully-funded project on measurement of magnetic fields has begun at the University of Strathclyde, which will push the attainable sensitive below the femtoTesla level (ten orders of magnitude below the Earth's magnetic field.) Using compact, room temperature, atomic samples the new lab will compete directly with superconducting quantum interference device (SQUID) based systems that require prohibitively expensive cryogenic environments. The outcomes of the project will be immediately applied to measurement of bio-magnetic fields, in particular to magnetic fields produced by the neuronal electrical activity of the human brain.

The successful candidate is expected to have the dedication and enthusiasm for experimental research, along with strong communication skills. In return, we offer an opportunity to join a project that is at the centre of a major UK investment in Quantum Technologies. You will be embedded within a hub of internationally leading researchers with direct links to industry, national research labs, and the most advanced research equipment. We also offer cutting-edge research training in metrology and atomic physics.

This one of three fully-funded PhD positions available in the Optics Division of the Department of Physics at the University of Strathclyde. Funding is available for 3.5 years for UK or EU nationals. All fees are paid together with a tax-free stipend. The Optics Division will be a focal point of the EPSRC Quantum Technology Hubs, and has received significant funding from the recent call to expand our multi-disciplinary research in both experimental and theoretical fields. 

We also offer postgraduate teaching and training as part of the SUPA(Scottish Universities Physics Alliance) and IMPP (International Max Planck Partnership). Financial support is available for collaborative work and for presentation of results at national and international conferences. Applicants should have an excellent first degree in Physics, Engineering, or a related discipline.

John Jeffers, CNQO

Quantum Optical State Comparison Amplification
A theoretical project based on extending the theory of amplification of coherent states for quantum communication - a possible signal repeater for the quantum internet. The two mechanisms for this are state comparison and photon subtraction. More details are in the reference. There is opportunity to work closely with experimentalists at another UK institution on fibre-based implementations. The project is linked to the Department's involvement in the new £24 million Quantum Communications QT Hub. 
References 

Quantum optical state comparison amplifier: Phys. Rev. Lett. 111, 213601 (2013).

Stefan Kuhr, Photonics

Quantum simulation with fermions in a quantum-gas microscope
In our lab we have the unique possibility to image fermionic atoms with single-atom resolution in optical lattices using a quantum-gas microscope [Nature Physics 11, 738-742]. This exquisite tool will be used for the quantum simulation of many-body phenomena, allowing us to probe the equilibrium and out-of-equilibrium properties of interacting fermions with an unprecedented insight into their local properties. These experiments will help uncover the fascinating physics of strongly-correlated systems, some of which cannot be computed even by state-of-the-art algorithms.
For further details, please contact Prof. Stefan Kuhr (stefan.kuhr@strath.ac.uk), Dr Bruno Peaudecerf (bruno.peaudecerf@strath.ac.uk), or visit http://photonics.phys.strath.ac.uk/single-atom-imaging/

We are looking for an enthusiastic and dedicated PhD student to join our team. The work involved is mainly experimental, but requires a good grasp of the underlying concepts of quantum physics. We have a fully funded PhD Studentship available starting from October 2016

Brian McNeil, CNQO

Future Light Sources

PhD Project Title: Future light sources

 

Supervisor (1): Dr Brian McNeil

 

Supervisor (2): Dr Gordon Robb

 

Project Description:

 

Free-Electron Lasers (FEL) use high energy electron beams produced by particle accelerators to generate intense electromagnetic within a long series of alternating dipole magnets called an undulator. The wavelength output from these sources ranges from mm-waves into the hard X-ray [1].  Due to a lack of alternative sources, FELs operating in the X-ray (XFEL) are of particular interest and are now generating significant international interest. Examples of the first of these sources include the LCLS at SLAC in California [2], SACLA at Spring-8 in Japan [3] and European XFEL in Hamburg, Germany [4].

 

The spatial and temporal resolution available from the high brightness ultra-violet to x-ray pulses generated by these XFELs, is making feasible the observation and ultimately the potential to control ultra-fast, optionally non-linear processes in all forms of matter. With the ability to probe correlated electronic processes within atoms at short timescales, to measure how electrons and nuclei re-organise themselves, either individually within atoms due to external stimulus, during molecular bond making and breaking, or while undergoing subtle catalytic or biological processes, we can begin to unravel how all matter functions at this fundamental level.

 

The supervisors of this project Dr Brian McNeil and Dr Gordon Robb, have an extensive publication record in FEL theory and have developed many internationally recognised contributions to the field.  Dr McNeil works closely with the UK's Accelerator Science and Technology Centre. In the UK he is closely involved with the proposed CLARA facility based at Daresbury near Warrington [5].

 

This project will involve using the coupled Maxwell and Lorentz force that describe the FEL process to investigate new and important improvements to FEL operation. Examples of previous research by the Supervisor’s group include the generation of ultra-short pulses [6], greatly improved temporal coherence [7], multi-colour operation [8] and use of ‘beam-by-design’ [9]. To facilitate the study of such systems a unique computer code has been developed [10]. This code will be used in the further development of new and improved methods of FEL operation. For example, multi-colour and broad bandwidth operation, and investigations of how FELs can be driven by plasma-accelerators. It is expected that such developments may be able to be tested at the proposed CLARA facility [3] which is being developed for this purpose. New opportunities also exist in describing the FEL quantum-mechanically which may allow investigation of the interaction in to the gamma-ray region of the spectrum – an exciting prospect not yet achieved.

 

References:

[1] McNeil & Thompson, Nature Photonics, 4, 814, 2010

[2] https://portal.slac.stanford.edu/sites/lcls_public/Pages/Default.aspx

[3] http://xfel.riken.jp/eng/

[4] http://www.xfel.eu/

[5] http://www.stfc.ac.uk/ASTeC/Programmes/38749.aspx

[6] Dunning, McNeil & Thompson, PRL 110, 104801 (2013)

[7] McNeil, Thompson & Dunning, PRL 110, 134802 (2013)

[8] Campbell, McNeil & Reiche, New J. Phys. 16, 103019 (2014)

[9] Henderson, Campbell & McNeil, New J. Phys. 17, 083017 (2015)

[10] Campbell & McNeil, Phys. Plasmas 19, 093119 (2012)

X-ray Free Electron Lasers using 'Beam by Design'

Supervisor (1): Dr Brian McNeil

Supervisor (2): Dr Alison Yao

Project Description: This PhD studentship is part of a joint collaboration between University of Strathclyde’s top-rated Department of Physics and the world leading Stanford University’s SLAC National Accelerator Laboratory based in California (https://www6.slac.stanford.edu/).The student will be based at Strathclyde, but will travel to Stanford as part of the collaboration investigating novel methods of generating high power, coherent X-ray output.

Stanford constructed the world’s first X-ray Free Electron Laser (FEL), the LCLS which was commissioned in 2009 (https://portal.slac.stanford.edu/sites/lcls_public/Pages/Default.aspx). The LCLS FEL generates output that is ~10 orders of magnitude brighter than conventional synchrotron sources of X-rays and is opening up completely new frontiers in science. They are now designing LCLS-II, a significant new and improved source (https://portal.slac.stanford.edu/sites/lcls_public/lcls_ii/Pages/default.aspx).

Strathclyde are also members of the Cockcroft Institute (https://www.cockcroft.ac.uk/), based at STFC Daresbury Laboratory. This institute is the leading accelerator and light source research collaboration in the UK and provides post-graduate lecture courses tailored to the needs of the PhD students of the Supervisors - the 1st Supervisor gives a course in Free Electron Lasers at the Institute. 

Strathclyde also has very close links with the UK CLARA FEL test facility which will investigate methods for the next generation of FELs such as a future UK X-Ray FEL that will offer increased brightness and shorter pulses to users. We also collaborate with partners at DESY in Hamburg and the Paul Scherrer Institute in Switzerland. 

The physics underpinning relativistic free-electron light-sources is an important and exciting area of research, yielding new tools like the Free Electron Laser (FEL) that are transforming scientific research [1]. With a peak brightness ten orders of magnitude greater than conventional synchrotron X-ray sources, they have the potential, for the first time, to simultaneously access the structure and dynamics of matter at its natural atomic length and time scales. This will make feasible the ability to observe, and perhaps ultimately to control, ultra-fast, optionally non-linear, atomic and possibly nuclear processes. With the ability to probe correlated electronic processes within atoms at these timescales, to measure how electrons and nuclei reorganise themselves - either individually within atoms due to external stimulus, during molecular bond making and breaking, or while undergoing subtle catalytic or biological processes - we can begin to unravel how all matter functions at this fundamental level. 

You would be involved in the theory and modelling of such sources - including highly non-linear pulse propagation, ultra-short pulse generation, harmonic generation, full 3-D simulation, FEL seeding options and start-to-end simulations - and will contribute to the research in the development of these exciting new light sources. Another option will be to extend the analysis to the generation of X-rays with Orbital Angular Momentum (OAM) – a property of light that at longer wavelengths has led to significant technological advances in optical trapping and manipulation, high resolution imaging and high capacity quantum communication systems. Software developed by the 1st Supervisor’s group is ideally suited to modelling X-ray OAM FELs [2], allowing further innovation to be explored, e.g. in the generation of Poincaré beams, an extension of OAM currently being researched by Dr Alison Yao (2nd Supervisor), who is a leading researcher in OAM in ‘conventional’ laser systems [3]. 

Applicants should have a good first degree or equivalent in Physical Science, excellent analytical and computational skills, and a willingness travel both nationally and internationally to work with our collaborators at Stanford and elsewhere and to attend conferences. Successful completion of this highly collaborative PhD should equip you with the skills and contacts to enable you to obtain employment at a host of new international projects and facilities. 

Start date is October 2017 (this is flexible) and the approximate stipend in the first year is £14,500 GBP.

References

[1] Brian WJ McNeil and Neil R Thompson, Nature Photonics, 4, 814 (2010) 
[2] E. Hemsing, A. Marinelli, and J. B. Rosenzweig, Phys. Rev. Lett. 106, 164803 (2011) 
[3] Alison M. Yao and Miles J. Padgett, Advances in Optics and Photonics 3, 161 (2011)

Daniel Oi, CNQO

Quantum Information Theory

Quantum information Processing (QIP) is a new scientific field that studies how information may be stored and manipulated in systems obeying the laws of quantum physics. Quantum systems lead to novel ways of information processing, such as quantum computation, cryptography and teleportation. However, building a real QIP device is a formidable challenge. This is because quantum systems are susceptible to noise, and too much noise removes any advantages that QIP has over conventional methods. However, the exact levels of noise required before this happens are still unknown, and there may even be regimes where noise may be helpful.

One EPSRC funded studentship is currently available in theoretical quantum information, specifically the relationship between decoherence, non-classicality, and the efficacy of quantum information tasks.

The applicant should have or expected to be awarded a minimum of a 2.1 degree in physics or a related subject. The ideal applicant should be curious, and should have an interest in developing their analytical and numerical skills. Details on stipend and eligibility are available on the EPSRC website.

Applications should be made as soon as possible.

Gian-Luca Oppo, CNQO

Theory and simulation of generation of frequency combs in micro-resonators

Frequency combs are spectra consisting of a series of discrete, equally spaced elements and form the modern standard of optical frequencies and clocks. Frequency combs led to the Nobel Prize in Physics to John Hall and Theodor Hänsch in 2005. Micro-resonator-based frequency combs have attracted a lot of attention for their potential applications in precision metrology, gas sensing, arbitrary optical waveform generation, quantum technologies, telecommunication and integrated photonic circuits. Micro-resonator combs are generated in ultra-high-Q optical resonators that enable the confinement of extremely high optical power levels in very small mode-volumes. The high optical power densities lead to the conversion of a continuous wave laser into a comb of equidistant optical modes that can be used like a ruler for optical frequency measurements. Dr. Pascal Del’Haye of the Optical Frequency Standard section of National Physics Laboratory (NPL) directed by Dr. Patrick Gill has developed and optimised micro-resonator frequency combs based on periodic and soliton like wave-forms of the light circulating in the optical cavity. These are the temporal counterparts of periodic and cavity-soliton solutions discovered and analysed in the Computational Nonlinear and Quantum Optics (CNQO) group at Strathclyde for more than ten years. The project develops, optimises, and strategically compares accurate mathematical models for the generation of frequency combs in micro-resonators in a close connection with the experiments performed at NPL in Dr. Del’Haye’s laboratory.

The project will run in a close collaboration between Strathclyde and NPL. The CNQO group at Strathclyde is in a unique and strategic position world-wide being the inventor of the theory and first developer of the simulations associated with cavity-solitons, the key elements of the optimal frequency-comb generation using resonators. Dr. Del’Haye will be the external supervisor of the PhD student who will periodically visit NPL and compare the results of the simulations and theoretical models with the experimental data.

Francesco Papoff, CNQO

Sensitivity and reproducibility of fluorescence and Raman signals in nanostructures
With the recent revolution in detection technology, a single molecule interacting with metallic nanoparticles can produce a clear signal. Unfortunately this technique is not easily reproducible and there are many experimental aspects of it, for example bright blinking lines in the detection light signal, that have no or even contradictory theoretical explanations. We will address these issues by developing a new and more powerful theoretical model of the interaction between molecules, nanoparticles and light. We will not make a priori hypotheses, but will let the dynamics tell us who are the key players at each instant of the detection process.
Quantization of surface plasmon-polariton modes of nanostructures
Hyperspectral laser arrays based combination parametric resonances
The aim of this project is to design new and more complete ways to characterize the properties of matter through its images. As each property is associated to a specific light frequency, we need a combination of lasers operating over a broad range of frequencies. Synchronizing the lasers will allow us to extract information from both amplitudes and phases of all the spectral components of the images, substantially enhancing the resolution. We will achieve this by investigating theoretically arrays of coherent and phase-locked lasers operating at different frequencies and based on newly discovered combination parametric resonances.

Francesco Papoff & Benjamin Hourahine, CNQO & SSD

Extreme resolution nanophotonics

Recent progress in strong confinement and enhancement of light has allowed researchers to detect signals from single molecules close to nano-particles and is also investigated intensively as a way to optically transport and store information in extremely small regions. Characteristic optical behaviours of nanostructures are of great significance, not only for basic physical science but also as fundamentals for novel technologies in the environmental, medical, biological, and information sciences.  

This project is part of a new collaboration with the experimental group of Prof H. Okamoto at the Institute for Molecular Science (Japan) and will involve visits to that group. We want to combine our newly developed theoretical framework with our partner's nano-optical experiments, to understand and control the fundamental light-particle interaction processes. This will open the way to new applications and reliable devices for sub-wavelength information processing, enhanced photochemical processes and spectroscopic analysis. 

The response of a particles to light is similar to the playing of a musical instrument - they have intrinsic resonant modes characteristic of the particle (corresponding to the instrument) but the emitted waves depend on the specific way energy is applied (by whom and how it is played). There are many computational methods to calculate the response of nanoparticles to applied light, but none is explicitly based on the concept of these modes (or can provide a clear framework to understand how the response varies with the incident field). This project uses a new theoretical method, which can provide this information, and is ideally matched by our experimental partner's ability to image light extremely close to nanoparticle surfaces. Together we will visualize, identify and control the nanoscale resonant and non-resonant modes underpinning the optical behaviour of nanoparticles. 

This project should appeal to enthusiastic candidates with backgrounds in theoretical and computational physical science. Much of the day-to-day work of this project will involve applying concepts of advanced electromagnetism to modeling and computational simulations. Programming skills, while useful, are not a necessary prerequisite.

References

Geometrical Mie theory for resonances in nanoparticles of any shape, F. Papoff and B. Hourahine, Optics Express, Vol. 19, Issue 22, pp. 21432-21444 (2011), http://dx.doi.org/10.1364/OE.19.021432

Marco Piani, CNQO

Quantum correlations and quantum coherence in quantum information processing
Quantum correlations — including quantum entanglement, quantum non-locality, and quantum steering — and quantum coherence are at the core of quantum mechanics, and nowadays find application in newly developed quantum technologies, which go from quantum cryptography, to quantum metrology, to quantum computing. The project regards the operational qualitative and quantitative characterization of such fundamental quantum phenomena, leading to a better understanding and exploitation of such properties, in particular in — but not limited to — the area of metrology in noisy conditions.

Erling RiisPhotonics

Laser cooling and Bose-Einstein condensation

Bose-Einstein condensates made by laser cooling and evaporative cooling of atoms are the coldest known substance and are beginning to find a wide range of applications from understanding fluids to precision measurements. Most Bose-Einstein condensate to date are based ‘one-electron atoms’, i.e. the atomic structure is determined by a single electron outside a charged core. This generally leads to an atomic structure ideal for laser cooling but without any particularly narrow spectral lines that would be ideal for precision measurement or optical clocks. On the other hand, the two-electron atoms (such a calcium) offer narrow lines associated with transitions, where an electron spin flips, and are still relatively easy to laser cool.

The narrow transition in atomic calcium is key in this project. It will enable us to laser cool the atoms all the way to Bose-Einstein condensation – something that has not been possible to do with other atoms. An essential part of this is to trap the atoms in the strong light field of a CO2 laser in order to prevent them from falling under gravity while they are slowly cooled on the narrow line.

The direct laser cooling to condensation is radically different from the traditional approach, which relies on atomic collisions. It will therefore provide new insight into the formation of condensates. The CO2 laser offers a wide choice of geometry for the condensate. We can generate condensates in 1, 2 and 3 dimensional lattices and study the interaction of many independently created condensates when they are allowed to ‘see’ each other due to quantum mechanical tunnelling through the separating barriers.

Precision metrology for atomic clocks and quantum sensors
Atomic clocks are a shining example of the power that technology based on atomic physics can have. In the last decades, using atoms laser cooled to the microKelvin regime, the sensitivity of atomic clocks has increase to now being better than one second over the age of the universe. This project, a key node in the £50million Quantum Metrology and Sensors QT Hub, will focus on the construction of an atomic clock in a compact and robust package, utilising holographic technologies developed in our group at Strathclyde [Nat. Nanotech. 8, 321 (2013)]. The resulting device will surpass current state-of-the-art in commercial atomic clocks in cost, size, and stability. The successful candidate will gain cutting edge experience in atomic physics, lasers, optics, and vacuum technology.
A structured light laser
A picture is worth a thousand words; and in a very real sense, images encoded in the profile of a laser provide a highly efficient method to encrypt and convey information. Light profiles that carry orbital angular momentum (OAM) present a particular set of complex images, with advanced generation and detection technology already in place – even for single photons. In this PhD project – funded by the Leverhulme Trust and in collaboration with the University of Glasgow – you will demonstrate storage and processing of OAM information in a rubidium vapour. You will support shifts between differently coloured images and build a dynamically controlled OAM light laser – elements required for a true OAM quantum network.

G. Walker, A.S. Arnold and S. Franke-Arnold, Phys. Rev. Lett. 108, 243601 (2012).
Next-generation magnetometry
The sensitivity of quantum measurement has now increased to the point that we can measure, using atomic spectroscopy, the energy shifts due to magnetic fields below the picoTesla level. This scale, one hundred million times weaker than the Earth’s magnetic field, is particularly interesting as it is in the range of the fields produced at the scalp by activity in the human brain, which opens the exciting prospect of low-cost, high-sensitivity, and high-spatial-resolution brain scanners with features beyond state-of-the-art MRI or PET scanners. This project, part of the £50million Quantum Metrology and Sensors QT Hub, will deliver a precise magnetic sensors based on atomic physics with mm-scale resolution. New techniques for probing the interaction of atoms with magnetic fields will be developed, along with ultra-compact laser and optical technologies. The successful candidate will gain cutting edge experience in atomic physics, lasers, and optical technology.

Luca Tagliacozzo, CNQO

Joint Strathclyde/ICFO PhD position on the quantum many body problem

The many body problem - How is it possible that the same and simple constituent atoms, when joined together, produce such a beautiful and diverse world? One can see this as a consequence of collective emergence, an aspect of physics relevant to several disciplines, from statistical physics to condensed matter, to high energy physics.

We will address collective emergence in the framework of quantum many-body systems described through tensor networks. By using tensor networks, the states of many-body system are described efficiently by means of the contraction of a network of small constituent tensors, making such a description viable also for large systems. Tensor networks thus offer a rich and ideal playground for analytical and numerical studies of many-body problems.

We are looking for a talented PhD student who wants to embark on the development of tensor networks techniques, either in the context of strongly interacting 2D system or in the context of the out-of equilibrium evolution of 1D quantum systems. The ideal candidate should have good analytical and numerical skills, be highly motivated, and be enthusiastic about joining a very active area of research. The PhD candidate will work under the direct supervision of Dr. Luca Tagliacozzo in the CNQO group of the Department of Physics at the University of  Strathclyde in collaboration with Prof. Maciej Lewentstein at ICFO.

The proposed theoretical studies will also be relevant for ongoing experimental efforts, including work being performed in the Experimental Quantum Optics and Photonics Group in the Department of Physics of the University of Strathclyde.

The available PhD is part of the ongoing collaboration between Dr. Luca Tagliacozzo at Strathclyde and the QOT group of Prof. Maciej Lewenstein at ICFO. The candidate will be based at Strathclyde, but will spend a significant amount of time at ICFO in Barcelona. We also offer postgraduate teaching and training as part of the SUPA (Scottish Universities Physics Alliance) and IMPP (International Max Planck Partnership). Financial support is available for collaborative work and for  presentation of results at national and international conferences.

Applicants  should have an excellent master degree in Physics, Applied Mathematics, Engineering, or a related  discipline. Applications should be made by email directly to Luca Tagliacozzo and should include a CV and at least 2 letters of recommendations.

Alison YaoCNQO

Control and applications of structured light and chiral molecules

Fully-structured light – light that has non-uniform intensity, phase and polarization – lies at the heart of an emerging and extremely promising field of research, with applications in high-resolution imaging, optical communications, and trapping and manipulation of nanoparticles. This project aims to significantly advance the theory of this emerging and extremely promising field of research for important and promising applications in photonics and molecular chemistry.

The PhD project will focus on:

  • Design of novel light beams for interaction with chiral molecules
  • Numerical simulations of nonlinear propagation of fully-structured light
  • Interaction of light with, in particular, chiral molecules

The project, part-funded by the Leverhulme Trust, will offer the opportunity to work in an exciting cross-disciplinary area and provide research training in fundamental electromagnetism, numerical and analytical methods for nonlinear beam propagation and some molecular chemistry. The Department also offers postgraduate teaching and training as part of the SUPA (Scottish Universities Physics Alliance).

The successful applicant should have a good first class degree or equivalent in a Physical or Chemical Science and dedication and enthusiasm for research in both theoretical optics and molecular chemistry. They should also have excellent analytical and computational skills, very good communication and interpersonal skills and a willingness to travel both nationally and internationally to present results at national and international conferences. Start date is October 2017.

For further information on the PhD project contact Dr Alison Yao (alison.yao@strath.ac.uk).

Plasmas Division

Bernard Hidding, SILIS

Beam-driven plasma wakefield acceleration at Strathclyde/SLAC/UCLA/RadiaBeam

We are on the quest towards 5th generation light sources and ultracompact electron accelerators - the time-resolved microscopes of the 21st century. Motivated and excellent PhD candidates, ideally with a background in laser and/or beam driven plasma wakefield acceleration are required to help lay the foundations for this. Our approach is to combine the best of beam-driven plasma wakefield acceleration (PWFA) as well as laser wakefield acceleration (LWFA) to generate the highest quality electron bunches ever produced. These will then be essential ingredients for highest performance future light sources such as FELs. International flagship experiments (at conventional accelerators such as E-210 "Trojan Horse" at FACET/SLAC, at FLASHForward, and at CLARA/Daresbury) will be complemented by hybrid LWFA experiments at laser-plasma-accelerators worldwide. In addition, first-class high performance computers and state-of-the-art simulation codes (particle-in-cell etc.) will be used to model the interaction, and to help understand it theoretically. The electron beam driver will set up the plasma wave, and a low energy laser pulse will ionize an additional plasma component locally within this plasma wave. This leads to ultracold bunches, which are a prerequisite for the ultrahigh bunch quality. These bunches would not even have a quality in terms of emittance which is far better when compared to other plasma-based approaches, but also would have better beam quality in many regards than the best bunches from conventional accelerators such as the LCLS in terms of (5D) brightness, for example.

The E210 "Trojan Horse" collaboration Srathclyde-SLAC-UCLA-Hamburg et al. was concluded with breakthrough results in spring 2016 in the final run of FACET’s lifetime, tight in time before shutting down to make way for LCLS-II. Now, the exploitation phase of the accumulated data has begun, in which the PhD student would participate. At the same time, the preparation time for SLAC FACET-II, the new advanced accelerator test facility at SLAC, has started and will be a focus for the PhD student.

The PhD candidate would work in a truly international and multi-disciplinary collaboration, being based at the Scottish Centre for the Application of Plasma-based Accelerators (SCAPA) in Glasgow. SCAPA is the flagship project of SUPA, the biggest physics alliance in the UK. It is located in the heart of Glasgow as part of the University of Strathclyde and the Technology Innovation centre TIC. Our goal is to demonstrate the novel scheme, build light sources (FEL, Thomson etc.) which will exploit the bunch brightness and multi-bunch schemes, and then push it further to the industrial level. While being based at Glasgow, the student(s) would be placed on long-lasting research stays at SLAC, UCLA and at RadiaBeam (industry SME) in between Los Angeles and the Bay Area, to foster the intense collaboration between US and Strathclyde.

The student would be part of a new Strathclyde Centre for Doctoral Training (SCDT) P-PALS (Plasma-based Particle and Light Sources), and the Cockcroft Institute, the UK’s university-based centre for accelerator development.

If you are interested in a PhD in this environment and think you are fit, please contact Prof. Bernhard Hidding via email or phone, ideally prior to your formal application to dicuss the options.

The PhD student will be a student of University of Strathclyde as part of the newly created Strathclyde Centre for Doctoral Training P-PALS, but will be on extended research stays in the US at SLAC in Stanford, USA, and UCLA, Los Angeles, in order to carry through R&D which is crucial in the context of FACET-II, the successor of the world's pioneering beam-driven plasma wakefield accelerator facility FACET at SLAC.

References

Ultrahigh brightness bunches from hybrid plasma accelerators as drivers of 5th generation light sources, B. Hidding, G.G. Manahan, O Karger, A Knetsch, G Wittig, 
D A Jaroszynski, Z-M Sheng, Y Xi, A Deng, J B Rosenzweig, G Andonian,, A Murokh, G Pretzler, D L Bruhwiler and J Smith, J. Phys. B: At. Mol. Opt. Phys. 47 (2014) 234010 (invited)

Hybrid modeling of relativistic underdense plasma photocathode injectors, Y. Xi, B. Hidding, D. Bruhwiler, G. Pretzler, and J. B. Rosenzweig, PRSTAB 16, 031303 (2013)

Ultracold Electron Bunch Generation via Plasma Photocathode Emission and Acceleration in a Beam-driven Plasma Blowout, B. Hidding, G. Pretzler, J.B. Rosenzweig, T. Königstein, D. Schiller, D.L. Bruhwiler, Physical Review Letters 108, 035001, 2012

Beyond injection: Trojan horse underdense photocathode plasma wakefield acceleration, B. Hidding, J. B. Rosenzweig, Y. Xi, B. O'Shea, G. Andonian, D. Schiller, S. Barber, O. Williams, G. Pretzler, T. Königstein, F. Kleeschulte, M. J. Hogan, M. Litos, S. Corde, W. W. White, P. Muggli, D. L. Bruhwiler and K. Lotov, AIP Conf. Proc. 1507, 570 (2012)

, SILIS

Studies of the interaction of intense laser pulses with plasma as ultra-compact accelerators, plasma-based laser amplifiers, and coherent and incoherent attosecond x-ray sources

PhDs are offered in an exciting and challenging research area, with a vibrant group of experimentalists and theoreticians developing and applying ultra-compact accelerators and x-ray sources based on laser-plasma interactions. Students will have access to dedicated Strathclyde (ALPHA-X, SCAPA) and international (RAL, GSI, ELI etc) laser facilities. Strathclyde is an Associate Member of the Cockcroft Institute, which provides links to the accelerator community. All our research is collaborative, with the theoretical and experimental teams working closely together and interacting with international collaborators and visitors. Much of our work is cross-disciplinary e.g. radio-therapy studies based on laser-driven particle beams, which involves world-leading radiobiologists and medical physicists.

The group has made pioneering advances in laser-plasma wakefield accelerators (LWFAs) and radiation sources based on them. A diverse range of topics is available for study: laser-driven accelerators and radiation sources [1-4,8-10,13,17], high field physics and radiation reaction [6,7,12], coherence development, parametric processes [5], amplification in plasma [5,14-16], attosecond science, imaging, radiobiology using particles and radiation [11], free-electron lasers (FELs) based on plasma channels, etc. [4]

LWFAs can produce relativistic electron beams with energies up to several GeV by exploiting the large electric fields produced when intense laser pulses interact with plasma [1,3]. The group has demonstrated diverse applications of LWFAs, e.g. as driving compact synchrotron sources [21], gamma ray production [1] and radiotherapy [15]. The accelerating structure of the LWFA consists of a string of micron-sized “bubbles” of evacuated regions of plasma that are created by the combination of the ponderomotive force of intense, ultra-short laser pulses and the restoring force of the ions on displaced plasma electrons. Electrons can be injected into this structure from background plasma, which results in high brightness particle beams are produced with narrow energy spreads less than 1 percent [1,23], low emittance less than 1 pi mm mrad [18] and ultra-short duration, <1 femtosecond. These attractive parameters should make them suitable for driving compact FELs [5], which would drastically reduce their size (from kms to metres!). PhD students will have the opportunity of working on this revolutionary technology, which could change the way science is done by making ultra-compact radiation sources widely available.

Stimulated Raman and Compton backscattering in plasma are potential methods of amplifying laser pulses to reach exawatt powers because plasma can withstand extremely high electric fields and has unique nonlinear optical properties [5,14-16]. The Strathclyde group studies Raman chirped pulse amplification (CPA) using an ultra-short probe (seed) pulse interacting with a long 1-2 J counter-propagating chirped pump pulse in a capillary discharge plasma waveguide. These are being extended to the high efficiency Raman/Compton regime using greater than 100 J pump pulses at RAL, where the group has demonstrated the highest power amplified probe pulses to date. Higher energy Raman-CPA studies will continue at SCAPA in 2015, when facilities become available. Theoretical studies use both particle-in-cell simulations and reduced models to investigate the nonlinear regimes and efficiency. PhD projects in this area offer an opportunity to study a completely new way of amplifying light, which could pave the way towards the world’s most powerful lasers.

To explore high field physics the group is investigating Compton scattering, where momentum is exchanged between an electron and a photon. This process is central to experiments at SCAPA, RAL 10 PW and ELI, where electron bunches will interact with intense laser pulses. By developing computationally efficient models of nonlinear Compton scattering, we are investigating how this and related fundamental processes (such as radiation reaction and the Cherenkov effect) [6,7,12] will affect properties of the electron bunch, and how this will be reflected in the radiation spectrum. PhD students will have the opportunity to work in a completely new area of fundamental physics based on high power lasers.

PhD training will be given through advanced courses via the SUPA Graduate School, and tailor made residential courses, involving collaborators, for in-depth research and transferable skills training. The group has an excellent reputation in placing PhD graduates in industry, large facilities and academia. Several joint ELI-Strathclyde studentships are available on topics relevant to ELI. The Extreme Light Infrastructure (ELI) consists of three unique EU facilities applying high power lasers.

Funding Notes

Some PhD funding has nationality restrictions e.g. EU and/or UK. Please send email to inquire.

References

1. S Cipiccia, et al., “A Harmonically Resonant Betatron Plasma Wakefield Gamma-Ray Source”, Nature Phys. 7, 867 (2011)

2. HP Schlenvoigt, et al., “A compact synchrotron radiation source driven by a laser-plasma wakefield accelerator”, Nature Physics 4 130 (2008)

3. SPD Mangles, et al., “Monoenergetic beams of relativistic electrons from intense laser–plasma interactions” Nature 431, 535 (2004)

4. DA Jaroszynski et al., “Radiation sources based on laser–plasma interactions”, Phil. Trans. R. Soc. 364, 689-710 (2006)

5. B Ersfeld and DA Jaroszynski, “Raman Backscattering of a Chirped Pump in Plasma”, Phys. Rev. Lett. 95, 165002 (2005)

6. A Noble and D Burton, “Aspects of electromagnetic radiation reaction in strong fields”, Contemporary Physics (2014)

7. D Burton and A Noble, “On the entropy of radiation reaction”, Phys. Lett. A 378, 1031 (2014)

8. C Ciocarlan, et al., “The role of the gas/plasma plume and self-focusing in a gas-filled capillary discharge waveguide for high-power laser-plasma applications”, Physics of Plasmas, 20, 093108 (2013)

9. S Cipiccia, et al., “Compton scattering for spectroscopic detection of ultra-fast, high flux, broad energy range X-rays”, Rev. Sci. Instr. 84, 113302 (2013)

10. S Cipiccia, et al., “A tuneable ultra-compact high-power, ultra-short pulsed, bright gamma-ray source based on bremsstrahlung radiation from laser-plasma accelerated electrons,” Journal of Applied Physics 111 (2012)

11. V Moskvin, et al., “Characterization of the Very High Energy Electrons, 250 MeV (VHEE) Beam Generated by ALPHA-X Laser Wakefield Accelerator Beam Line for Utilization in Monte Carlo Simulation for Biomedical Experiment Planning”, Medical Physics 39, 3813 (2012)

12. Y Kravets, et al., “Radiation reaction effects on the interaction of an electron with an intense laser pulse”, Phys. Rev. E 88, 011201(R) (2013)

13. E Brunetti, et al., “Low emittance, high brilliance relativistic electron beams from a laser-plasma accelerator”, Phys. Rev. Lett. 105, 215007 (2010)

14. G Vieux, et al., “Chirped pulse Raman amplification in plasma”, New J. Phys. 13, 063042 (2011)

15. JP Farmer, et al., “Raman amplification in plasma. Wavebreaking and heating effects,” Physics of Plasmas 17 (2010) 
 16. B Ersfeld, et al., “The role of absorption in Raman amplification in warm plasma,” Physics of Plasmas 17 (2010)

Paul McKenna, SILIS

High energy ion acceleration in ultra-intense laser-plasma interactions
Laser driven radiation as an advanced imaging source
Energetic Electron Transport in Solids Irradiated by Ultraintense Laser Pulses

Martin O'Mullane, ABP

Divertor Spectroscopy in the MAST-Upgrade Tokamak
An exciting opportunity is available for a PhD student to participate in diagnostic analysis at the MAST-Upgrade fusion device, under construction at the Culham Centre for Fusion Energy (CCFE). The student will investigate mechanisms related to particle and power exhaust with a novel Super-X divertor using sophisticated diagnostics to explore the complex interaction between the plasma, solid surfaces, atoms and molecules in the divertor region. 

The studentship is a 3.5 year Engineering and Physical Sciences Research Council (EPSRC) CASE award with CCFE as the sponsoring industrial partner. Full funding (fee and stipend) are available for UK students and fees for non-UK resident EU students. Under the increased flexibility mechanism of EPSRC, outstanding EU students may be eligible for full funding.

The project will be to participate in the collection of spectral information from experiments in MAST-Upgrade using grating spectrometers, filtered cameras and other instruments. A principal aim will be the interpretation of the spectral measurements using atomic models and data from the Atomic Data and Analysis Structure (ADAS). A second aim will be the use of interpretative transport modelling (especially SOLPS and DIVIMP) to collate and interpret the role of atomic and molecular processes governing the fluxes of heat and particles to the divertor plasma-facing surfaces, and to characterize the plasma conditions (electron temperature, density, impurity species temperature) in the divertor region. In developing these aspects the student will be expected to engage with pan-European modelling teams.

The successful applicant will have a good honours degree in physics or a related discipline. The student will be registered for a PhD at the Department of Physics, University of Strathclyde but will be based at CCFE, near Oxford, where the development will take place following initial training at the Department in Glasgow. All necessary supplementary training will be provided as part of the European skills development programme for fusion.

For more information please contact Dr. Martin O’Mullane (martin.omullane@strath.ac.uk).

Zhengming Sheng, SILIS

Theoretical and numerical studies on laser-plasma based advanced particle beams and radiation sources
The recent development of laser technology has made extreme high power lasers available even in a university laboratory, with peak power around 1PW (1PW=10^15 W). The European project ELI (Extreme Light Infrastructure) will be capable of delivering laser pulses even over 10PW, pushing the laser-matter interactions to a new limit. This PhD project will deal with extreme nonlinear physics in such laser-matter interactions and their applications in advanced particle accelerators and radiation sources (from THz to X-rays). It involves large scale of numerical simulations and will also support the relevant experimental activities at Strathclyde.

Institute Of Photonics

Jennifer HastieInstitute of Photonics

Compact, diamond-cooled and stabilised semiconductor disk lasers for quantum technology

Start date: September 2017

Duration: 4 years, including 1 year integrated MSc

This project is part of the EPSRC Centre for Doctoral Training in Diamond Science and Technology and includes a specially-designed one year MSc course at the University of Warwick and two mini-projects with collaborators during the summer of 2018; one at the University of Bath and one at the Fraunhofer Centre for Applied Photonics.

Eligibility: Funding available for UK and EU nationals only

Background: Semiconductor disk lasers (SDLs) consist of an optically-pumped multi-quantum well active mirror in an external laser cavity. This format of semiconductor laser has a number of advantageous characteristics including power scaling with high beam quality, easy access to high intracavity power, and wavelength flexibility. Following the development of diamond-cooled AlGaInP-based red SDLs at the IoP, we are able to implement intracavity frequency doubling to reach ultraviolet wavelengths [1]. SDLs are unique among semiconductor lasers in that they have very high finesse external cavities with high power and therefore their intrinsic linewidth is very narrow. They also have very low intensity and frequency noise compared to other lasers so long as the photon lifetime exceeds the carrier lifetime; however, this means that the external cavity must be a few cm long and therefore subject to environmental noise. Linewidths of a few kHz are usually achieved via active stabilisation to an external reference, most often a Fabry Perot. We have recently reported a 689nm SDL with linewidth of 5kHz for strontium atom cooling applications and demonstrated tuning with picometre precision via an intracavity diamond heatspreader acting as a variable etalon [1]. A broad range of compact ultra-narrow linewidth lasers, at novel wavelengths, are required for quantum technology; specifically metrology (based on optical clocks) where we aim to apply short wavelength (visible – ultraviolet) SDLs in collaboration with UK leaders in quantum science.

Project objective: In this project the student will develop narrow linewidth, diamond-cooled and stabilised SDL systems suitable for application in quantum technology.  This work will take full advantage of the properties of diamond: enabling high power operation and providing thermal and mechanical stability.  The research may include but is not limited to: design and optimisation of semiconductor gain structures, semiconductor processing, diamond processing, laser cavity engineering, optics and nonlinear optics, active stabilisation techniques and atom optics demonstrations with our collaborators.  We will target novel results that will be published in the best journals in the field. 

Research environment: This studentship will benefit from and contribute to a wider project supported by the EPSRC UK Quantum Technology Hub for Sensors and Metrology (www.quantumsensors.org), which involves multiple academic and industry partners.  Dr Hastie leads the ‘Special Lasers’ workpackage of the Hub, developing narrow linewidth lasers at novel wavelengths for the optical clock systems of the other partners.  We have an existing collaboration with the group of Hub Director Prof Kai Bongs at the University of Birmingham, using these lasers for cooling strontium.  Dr Hastie is also the academic partner in an Innovate UK project in collaboration with the Fraunhofer Centre for Applied Photonics and M Squared Lasers Ltd to support the translation of the group’s laser technology to industry.  

How to apply: In the first instance applicants should send a CV to iop@strath.ac.uk.

The formal application submission is a two-step process. You must apply to BOTH Warwick for the MSc using the Warwick Online Application form – state MSc in Diamond Science and Technology – and your host institution for PhD studies. Further information can be provided by contacting dst.admin@warwick.ac.uk.

[1] David Paboeuf and Jennifer E. Hastie, “Tunable narrow linewidth AlGaInP semiconductor disk laser for Sr atom cooling applications,” Applied Optics 55, 4980 (2016).

Martin Dawson and Michael Strain, Institute of Photonics

High speed, ultra-low photon flux imaging

Start date: October 2017

Duration: 3.5 years 

Eligibility: Funding available for UK and EU nationals only

This project is part of a collaboration with the Fraunhofer Centre for Applied Photonics (FCAP), UK. The successful applicant will have the opportunity to work in the FCAP laboratories and gain first-hand experience in industrially relevant research and development projects.

Background: The development of imaging systems has historically been focussed on the design of optics and camera technologies for the direct viewing of distant or microscopic objects. Recent, major advances have been made in light sources, photodetectors and electronics that open up a whole new range of techniques, including: single pixel cameras , ghost imaging, wide field high-resolution microscopy and single photon imaging. These methods are allowing scientists and engineers to see more spatial, temporal and spectral detail than ever before.

Future systems require performance that goes well beyond simple image capture. Accurate timing information provides access to 3D imaging techniques, while smart image processing and spatially tunable optics can produce sub-diffraction limited images of neural cells and reaction pathways. Operation of cameras in the few photon limit can make use of correlation effects, beating classical limits and offering security. To enable these kinds of imaging applications optical sources must be considered in parallel with the detector technologies.

At the Institute of Photonics we have been developing micro-LED display technologies with remarkable performance parameters. Each pixel is only a few tens of microns in diameter and can be switched at 100’s of MHz rates, with pulse widths of nanosecond duration.  Arrays of these pixels are bonded directly onto CMOS drive electronics providing unprecedented control over their spatio-temporal output. The spatially structured light-field gives access to an entirely new form of illumination that has shown application in visible light communications and indoor navigation.

Project objective: This project will develop the potential of spatio-temporal illumination sources further, targeting their operation at ultra-low light levels in the single photon range.  By using Single Photon Avalanche Detector (SPAD) arrays, we will be able to create correlations of generated and detected photons in both space and time.  This ability will allow the capture of images with extremely few photons, combined with sparse image processing techniques.  The applications of these imaging systems include low flux biological systems, underwater data communications and navigation, and quantum imaging and robotic control.

The PhD student will have access to state-of-the-art LED and SPAD arrays with which to create next generation imaging systems.  They will develop spatio-temporal modulation and decoding schemes for low flux imaging and navigation, implementing these using custom electronics.  The systems will be demonstrated in macro and micro-scale imaging applications.

This studentship will benefit from and contribute to a wider project supported by the EPSRC UK Quantum Technology Hub for Quantum Enhanced Imaging, which involves multiple academic and industry partners.  Prof. Dawson leads work on the development of structured illumination sources for imaging, navigation and communications.  

Training: In addition to the University of Strathclyde’s Postgraduate Certificate in Researcher Professional Development, which includes transferrable skills training, all our students are enrolled in the Scottish Universities Physics Alliance (SUPA) Graduate School for subject specific training.  Furthermore, students will enjoy access to and receive appropriate training for the use of any required equipment in the photonics and cleanroom facilities at the Technology and Innovation Centre and FCAP labs.

How to apply: Applicants should send a CV to iop@strath.ac.uk.

B. Sun, M. P. Edgar, R. Bowman, L. E. Vittert, S. Welsh, A. Bowman, and M. J. Padgett, "3D Computational Imaging with Single-Pixel Detectors", Science, vol. 340, no. 6134, pp. 844–847, 2013.

G. Zheng, R. Horstmeyer, C. Yang, G. Zheng, and C. Yang, "Wide-field, high-resolution Fourier ptychographic microscopy", Nat. Photonics, vol. 7, no. 9, pp. 739–745, 2013.

A. McCarthy, N. J. Krichel, N. R. Gemmell, X. Ren, M. G. Tanner, S. N. Dorenbos, V. Zwiller, R. H. Hadfield, and G. S. Buller, "Kilometer-range, high resolution depth imaging via 1560 nm wavelength single-photon detection", Opt. Express, vol. 21, no. 7, pp. 8904–15, Apr. 2013.

Johannes Herrnsdorf, Jonathan J. D. McKendry, Enyuan Xie, Michael J. Strain, Ian M. Watson, Erdan Gu, Martin D. Dawson, "High speed spatial encoding enabled by CMOS-controlled micro-LED arrays", Photonics Society Summer Topical Meeting Series (SUM) 2016 IEEE, pp. 173-174, 2016.