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.

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.

Optics Division

Thorsten Ackemann, Photonics

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)

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.

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 Riis, Photonics

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 Yao, CNQO

Engineering high amplitude spiral bandwidths for secure quantum communications
Quantum optics will play a key role in transforming future applications for secure communications. Quantum cryptography, based on correlations due to quantum entanglement, is the only provably secure form of communication but maximising the information data rate requires encoding each photon pair with a large amount of information. One way to boost data rates in optical communication is to use helical, or "twisted", light that carries orbital angular momentum (OAM).

Using a process known as spontaneous parametric downconversion (SPDC) it is possible to produce photons that are entangled in their OAM. Although the quantum nature of these photons and their potential for applications in quantum information has been clearly demonstrated, SPDC is an inherently inefficient process and is thus unlikely to fulfil practical needs. This project aims to unlock the data carrying potential of photons entangled in their OAM by using an optical parametric oscillator (OPO) to
amplify the entangled signal by several orders of magnitude.

By combining knowledge of the quantum properties of the downconverted states and numerical codes developed in the group, this project will investigate the generation and control of downconverted photons entangled in their OAM. While this is a purely theoretical project, there will be the opportunity to be work closely with leading experimenters both as part of the Quantum Enhanced Imaging Hub and as part of the International Max Planck Partnership.

We are looking for a motivated student with excellent theoretical and computational skills. The appropriate person will be capable of working alone or as part of a team and should have a keen interest in working closely with experimental colleagues.

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.

Plasmas Division

Bengt Eliasson, ABP

Numerical and theoretical study of the interaction between magnetised plasma and electromagnetic waves
This PhD project aims at building a theoretical and numerical model of the propagation of electromagnetic waves into a magnetised plasma, and to study the nonlinear interactions between the electromagnetic wave and the plasma. There is also a possibility at Strathclyde for the PhD student to carry out experiments using an existing linear magnetized plasma device, to test and confirm the theoretical and numerical models. 

A plasma is an ionised gas in which there are free electrons and ions so that the gas is electrically conducting. Plasmas are ubiquitous in space and laboratory. One outstanding example is the Sun, which to large extent consists of plasma. The Earth is surrounded by a plasma layer, the so-called ionosphere, which shields us from radiation and energetic particles from the sun, and in the laboratory, plasmas are artificially created and studied with application to magnetic confinement fusion and basic research. The Earth's ionosphere is magnetized by the geomagnetic field, and in the laboratory, an external magnetic field is used to confine the plasma and prevent it from escaping to the walls. The propagation of electromagnetic waves into a plasma is a non-trivial problem, but which has great practical applications. One of the main heating mechanisms planned for fusion devices such as ITER and MAST are via large amplitude microwaves injected into the magnetised plasma. Hence, the project has relevance to the study of microwaves propagating into magnetically confined plasma in the laboratory and in fusion devices, as well as to experiments involving radio waves injected into ionospheric plasmas from ground-based transmitters or from satellites surrounding the Earth and other planets in the Solar system.

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.

Michael Strain, Institute of Photonics

Diamond membrane devices for efficient coupling to vacancy centres

Start date: October 2017

Duration: 3 years

Eligibility: Funding available for UK residents only

This studentship will benefit from and contribute to a wider project supported by the EPSRC UK Quantum Technology Hub in Networked Quantum Information Technologies, which involves multiple academic and industry partners.  The NQIT programme is working towards building a quantum computer demonstrator, the Q20:20 engine, which demonstrates a networked, hybrid light-matter approach to quantum information processing.

Background: Synthetic diamond has previously found major applications in drilling and cutting tools, heat-sink technology for high power electronics, and optics for lasers and harsh environmental conditions.  Recent advances in the manufacturing methods to produce single-crystal diamond have enabled materials with ultra-high purity and low optical losses.  This in turn has facilitated the production of integrated optical devices in diamond for the first time[1].

In addition to its large bandgap and wide transparency range, diamond provides an ideal host matrix for a range of crystal defect centres.  For example, Nitrogen and Silicon Vacancy (NV, SiV) colour centres have the potential to act as solid-state nodes for light matter interaction that can be harnessed in quantum optics systems.  Solid-state nodes are mechanically stable, have the potential for scaling and can be integrated with standard optical devices on-chip for multiplexing and processing.

Currently, single crystal diamond is only available in small pieces with areas in the order of mm2.  This makes the fabrication of scalable integrated optical devices a challenging task[2].  In particular, the efficiency of coupling between optical modes and defect centre based qubits is crucial to the performance of solid state diamond quantum systems. 

Project objective: This project will develop optical technologies based on the fabrication of ultra-thin diamond membranes for quantum optical applications.   Bulk single-crystal diamond will be processed, using photolithography and plasma etching, into membrane devices only a few hundred nanometres thick.  Resonators, waveguides and nano-features will be etched into these diamond films to enhance optical coupling to the native defect centres.

The project will investigate two complementary routes for coupling to defect centres in diamond membranes.  The first method involves the fabrication of nano-pillars in thin film diamond to guide optical modes and project them vertically from the membrane surface.  The second method requires the micro-assembly of nanoscale pieces of diamond material (nano-diamonds), with embedded defects, onto resonant cavities in guided wave or free-space configurations. 

The student will undertake numerical simulation, micro-fabrication and optical characterisation of the diamond optical devices.  They will have access to state-of-the-art cleanroom fabrication facilities and optical laboratories for the creation and measurement of these cutting edge photonic components.

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.

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

[1] Y. Zhang, L. McKnight, Z. Tian, S. Calvez, E. Gu, and M. D. Dawson, “Large cross-section edge-coupled diamond waveguides,” Diam. Relat. Mater., vol. 20, no. 4, pp. 564–567, Apr. 2011.

[2] C. L. Lee, M. D. Dawson, and E. Gu, “Diamond double-sided micro-lenses and reflection gratings,” Opt. Mater., vol. 32, no. 9, pp. 1123–1129, Jul. 2010.