Prof. Walter Johnstone

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Prof. Walter Johnstone
PhD, BSc (Hons), CEng, FIET, CPhys, F. Inst P


Professor of Photonic Systems
Vice Dean [Research]
Faculty of Engineering

Royal College Building
Room 2.08
University of Strathclyde
204 George Street
G1 1XW, Glasgow, UK

email: w.johnstone@strath.ac.uk
Tel: +44 (0)141 548 2641

Prof. Walter Johnstone completed his education at the University of Strathclyde where he graduated with a BSc.(Hons) degree in Chemical and Material Sciences in 1977 and a PhD in Laser Physics in 1982. He is currently Professor of Photonic Systems and Vice Dean of the Faculty of Engineering at Strathclyde University where he has been a member of academic staff since 1986. Following senior management positions as Head of the Department of Electronic and Electrical Engineering and Associate Dean [International], he was appointed to the Vice Dean’s post with responsibility for Research and International Relations.

His research into optical waveguide components, fibre lasers, distributed fibre sensing systems and optical gas sensing has led to more than 200 technical publications and several patent applications. As well as carrying out basic research, his group is involved in the engineering of such systems for in situ industrial deployment. Recent research has led to two novel approaches in tuneable diode laser spectroscopy (TDLS) to enable calibration-free, accurate measurement of gas concentration, pressure and temperature in complex gas processing systems such as fuel cells at temperatures up to 1000oC and pressures of 5-8bar or in jet (gas turbine) engines at high temperature and high gas velocity.

In addition to his academic career, Prof. Johnstone holds Directorships at OptoSci Ltd and the Institute for System Level Integration (ISLI). OptoSci was established in 1994 and major product lines include a range of optical and fibre optic educator kits, optical instrumentation, optical fibre amplifiers and a range of optical gas sensors. ISLI provides major technical and education services to the semi-conductor and electronics industries.

During the years 1980 to 1985 he was employed by Pilkington Optronics Ltd. and held various project engineering and management posts involved in the research and development of high power lasers, optical fibre communication systems and lithium niobate integrated optics. In 1985 he was appointed to the post of Development Manager at Logitech Ltd. In this role he was a full member of the company's Management Board with responsibility for all technical functions including new product development.

Research Projects:

Selected publications:

Journals

  1. G Stewart, W Johnstone, J Bain, K Ruxton and K Duffin, "Recovery of absolute gas absorption line shapes using tuneable diode laser spectroscopy with wavelength modulation – Part 1: theoretical analysis" IEEE Journal of Lightwave Technology, 29, 6, pp. 811-821, 2011. DOI: 10.1109/JLT.2011.2107312
  2. J Bain, W Johnstone, K Ruxton, G Stewart, M Lengden and K Duffin, "Recovery of absolute gas absorption line shapes using tuneable diode laser spectroscopy with wavelength modulation – Part 2: Experimental Investigation" IEEE Journal of Lightwave Technology, 29, 7, pp. 987-996, 2011. DOI: 10.1109/JLT.2011.2107729
  3. M Lengden, R Cunningham and W. Johnstone, "Tuneable diode laser gas analyser for methane measurements on a large scale solid oxide fuel cell" Journal of Power Sources, 196, 20, pp. 8406-08, 2011. DOI: 10.1016/j.jpowsour.2011.06.020
  4. A. L. Chakraborty, K. Ruxton, and W. Johnstone, "Suppression of intensity modulation contributions to signals in second harmonic wavelength modulation spectroscopy", Optics Letters, Vol. 35, No. 14, pp. 2400-2402, July 2010. DOI: 10.1364/OL.35.002400
  5. I. Armstrong, W. Johnstone, K. Duffin, M. Lengden, A. L. Chakraborty and K. Ruxton , "Detection of CH4 in the Mid-IR using Difference Frequency Generation with Tunable Diode Laser Spectroscopy", IEEE Journal of Lightwave Technology, IEEE Journal of Lightwave Technology, Vol. 28, No. 10, pp. 1435-1442, February 2010. DOI: 10.1109/JLT.2010.2042789
  6. A. J. McGettrick, W. Johnstone, R. Cunningham and J. Black, "Tunable diode laser spectroscopy: calibration free measurements of gas composition at elevated temperature and pressure", IEEE Journal of Lightwave Technology, 27, 15, pp. 3150-3161, August 2009. DOI: 10.1109/JLT.2008.2008729
  7. A. L. Chakraborty, K. Ruxton, W. Johnstone, M. Lengden and K. Duffin, "Elimination of residual amplitude modulation in tunable diode laser wavelength modulation spectroscopy using an optical fiber delay line", Optics Express, Vol. 17, No. 12, pp. 9602-9607, June 2009. DOI: 10.1364/OE.17.009602
  8. W Johnstone, A J McGettrick, K Duffin, A Cheung and G Stewart, “Tunable diode laser spectroscopy for industrial process applications: system characterization in conventional and new approaches”, IEEE Sensors Journal, Vol. 8, No. 7, pp. 1079-88, July 2008. DOI: 10.1109/JSEN.2008.926167
  9. A J McGettrick, Duffin K., W Johnstone, G Stewart and D Moodie, "Tunable diode laser spectroscopy with wavelength modulation: a phasor decomposition method for calibration free measurements of gas concentration and pressure" IEEE Journal of Lightwave Technology, vol. 26, no. 4, pp. 432-440, February 2008. DOI: 10.1109/JLT.2007.912519
  10. K Duffin, A J McGettrick , W Johnstone, G Stewart and D Moodie, "Tunable diode laser spectroscopy with wavelength modulation: a calibration free approach to the recovery of absolute gas absorption line shapes" IEEE Journal of Lightwave Technology, vol. 25, no. 10, pp. 3114-3125, October 2007. DOI: 10.1109/JLT.2007.904937