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Zhang, Rui and Xia, Jiangnan and Ahmed, Ihab and Gough, Andrew and Armstrong, Ian and Upadhyay, Abhishek and Fu, Yalei and Enemali, Godwin and Lengden, Michael and Johnstone, Walter and Wright, Paul and Ozanyan, Krikor and Pourkashanian, Mohamed and McCann, Hugh and Liu, Chang (2023) A fast sensor for non-intrusive measurement of concentration and temperature in turbine exhaust. Sensors and Actuators B: Chemical, 396. 134500. ISSN 0925-4005
Fu, Yalei and Zhang, Rui and Xia, Jiangnan and Gough, Andrew and Clark, Stuart and Upadhyay, Abhishek and Enemali, Godwin and Armstrong, Ian and Ahmed, Ihab and Pourkashanian, Mohamed and Wright, Paul and Ozanyan, Krikor and Lengden, Michael and Johnstone, Walter and Polydorides, Nick and McCann, Hugh and Liu, Chang (2023) Hybrid model-driven spectroscopic network for rapid retrieval of turbine exhaust temperature. IEEE Transactions on Instrumentation and Measurement, 72. 2531710. ISSN 1557-9662
Upadhyay, Abhishek and Lengden, Michael and Enemali, Godwin and Stewart, George and Johnstone, Walter and Wilson, David and Humphries, Gordon and Benoy, Thomas and Black, John and Chighine, Andrea and Fisher, Edward and Zhang, Rui and Liu, Chang and Polydorides, Nick and Tsekenis, Alex and Wright, Paul and Kliment, Joshua and Nilsson, Johan and Feng, Yutong and Archilla, Victor and Rodriguez-Carmona, Javier and Sanchez-Valdepenas, Jesus and Beltran, Marta and Polo, Valentin and Armstrong, Ian and Mauchline, Iain and Walsh, Douglas and Johnson, Mark and Bauldreay, Joanna and McCann, Hugh (2022) Tomographic imaging of carbon dioxide in the exhaust plume of large commercial aero-engines. Applied Optics, 61 (28). pp. 8540-8552. ISSN 1559-128X
Fisher, Edward M. D. and Tsekenis, Stylianos-Alexios and Yang, Yunjie and Chighine, A. and Liu, Cheng and Polydorides, Nick and Wright, P. and Kliment, J. and Ozanyan, K. and Benoy, Thomas and Humphries, Gordon and Wilson, David and Lengden, M. and Johnstone, Walter and McCann, Hugh (2020) A custom, high-channel-count data acquisition system for chemical species tomography of aero-jet engine exhaust plumes. IEEE Transactions on Instrumentation and Measurement, 69 (2). pp. 549-558. ISSN 0018-9456
Crabb, Jonathan R. and Stevens, G. and Michie, C. and Johnstone, W. and Kehayas, E. (2019) Laser transmitter for cubesat-class applications. Proceedings of SPIE, 10910. 109101I. ISSN 0277-786X
Upadhyay, Abhishek and Lengden, Michael and Wilson, David and Humphries, Gordon Samuel and Crayford, Andrew P. and Pugh, Daniel G. and Johnson, Mark P. and Stewart, George and Johnstone, Walter (2018) A new RAM normalized 1f-WMS technique for the measurement of gas parameters in harsh environments and a comparison with 2f/1f. IEEE Photonics Journal, 10 (6). 6804611. ISSN 1943-0655
Polydorides, Nick and Tsekenis, Alex and Fisher, Edward and Chigine, Andrea and McCann, Hugh and Dimiccoli, Luca and Wright, Paul and Lengden, Michael and Benoy, Thomas and Wilson, David and Humphries, Gordon and Johnstone, Walter (2017) Constrained models for optical absorption tomography. Applied Optics, 57 (7). B1-B9. ISSN 1559-128X
Benoy, Thomas and Wilson, David and Lengden, Michael and Armstrong, Ian and Stewart, George and Johnstone, Walter (2017) Measurement of CO2 concentration and temperature in an aero engine exhaust plume using wavelength modulation spectroscopy. IEEE Sensors Journal, 17 (19). pp. 6409-6417. ISSN 1530-437X
Upadhyay, Abhishek and Wilson, David and Lengden, Michael and Chakraborty, Arup L. and Stewart, George and Johnstone, Walter (2017) Calibration-free WMS using a cw-DFB-QCL, a VCSEL, and an edge-emitting DFB laser with in-situ real-time laser parameter characterization. IEEE Photonics Journal, 9 (2). 6801217. ISSN 1943-0655
Benoy, Thomas and Lengden, Michael and Stewart, George and Johnstone, Walter (2016) Recovery of absorption line shapes with correction for the wavelength modulation characteristics of DFB lasers. IEEE Photonics Journal, 8 (3). 1501717. ISSN 1943-0655
Bain, James and Lengden, Michael and Stewart, George and Johnstone, Walter (2016) Recovery of absolute absorption line shapes in tunable diode laser spectroscopy using external amplitude modulation with balanced detection. IEEE Sensors Journal, 16 (3). pp. 675-680. ISSN 1530-437X
Bauer, Ralf and Legg, Thomas and Mitchell, David and Flockhart, Gordon M. H. and Stewart, George and Johnstone, Walter and Lengden, Michael (2015) Miniaturized photoacoustic trace gas sensing using a raman fiber amplifier. Journal of Lightwave Technology, 33 (18). pp. 3773-3780. ISSN 0733-8724
Murphy, Eoin and Michie, Craig and White, Henry and Johnstone, Walter and Andonovic, Ivan (2014) Power savings in a wavelength-division-multiplexed passive optical network for aircraft. Optical Engineering : Journal of the Society of Photo-Optical Instrumentation Engineers, 53 (12). 126109. ISSN 0091-3286
Bauer, Ralf and Stewart, George and Johnstone, Walter and Boyd, Euan and Lengden, Michael (2014) A 3D-printed miniature gas cell for photoacoustic spectroscopy of trace gases. Optics Letters, 39 (16). pp. 4796-4799. ISSN 0146-9592
Lengden, Michael and Cunningham, Robert and Johnstone, Walter (2013) Tunable diode laser based concentration measurements of water vapour and methane on a solid oxide fuel cell. Journal of Lightwave Technology, 31 (9). 1354 - 1359. ISSN 0733-8724
Lengden, Michael and Cunningham, Robert and Johnstone, Walter (2011) Tuneable diode laser gas analyser for methane measurements on a large scale solid oxide fuel cell. Journal of Power Sources, 196 (20). pp. 8406-8408. ISSN 0378-7753
Bain, James Roderic Peter and Johnstone, Walter and Ruxton, Keith Crawford and Stewart, George and Lengden, Michael and Duffin, Kevin (2011) Recovery of absolute gas absorption line shapes using tunable diode laser spectroscopy with wavelength modulation - Part 2 : experimental investigation. Journal of Lightwave Technology, 29 (7). pp. 987-996. ISSN 0733-8724
Stewart, George and Johnstone, Walter and Bain, James Roderic Peter and Ruxton, Keith Crawford and Duffin, Kevin (2011) Recovery of absolute gas absorption line shapes using tuneable diode laser spectroscopy with wavelength modulation- part 1 : theoretical analysis. Journal of Lightwave Technology, 29 (6). pp. 811-821. ISSN 0733-8724
Arsad, Norhana and Min, Li and Stewart, George and Johnstone, Walter (2011) Intra-cavity spectroscopy using amplified spontaneous emission in fiber lasers. Journal of Lightwave Technology, 29 (5). pp. 782-788. ISSN 0733-8724
Johnstone, Walter and Chakraborty, Arup Lal (2010) Quantitative wavelength modulation spectroscopy for gas measurements: elimination of laser intensity modulation effects. Proceedings of SPIE: The International Society for Optical Engineering, 8173. 1X.
Ruxton, Keith C. and Chakraborty, Arup Lal and Johnstone, W. and Lengden, Michael and Stewart, G. and Duffin, K. (2010) Tunable diode laser spectroscopy with wavelength modulation : elimination of residual amplitude modulation in a phasor decomposition approach. Sensors and Actuators B: Chemical, 150 (1). pp. 367-375. ISSN 0925-4005
Chakraborty, Arup Lal and Ruxton, Keith C. and Johnstone, W. (2010) Suppression of intensity modulation contributions to signals in second harmonic wavelength modulation spectroscopy. Optics Letters, 35 (14). pp. 2400-2402. ISSN 0146-9592
Armstrong, I. and Johnstone, W. and Duffin, K. and Lengden, Michael and Chakraborty, Arup Lal and Ruxton, Keith C. (2010) Detection of CH4 in the mid-IR using difference frequency generation with tunable diode laser spectroscopy. Journal of Lightwave Technology, 28 (10). pp. 1435-1442. ISSN 0733-8724
Stewart, G. and Johnstone, W. and Thursby, G.J. and Culshaw, B. (2010) Near infrared spectroscopy for fibre based gas detection. Proceedings of SPIE: The International Society for Optical Engineering, 7675. 767507.
Chakraborty, Arup Lal and Ruxton, Keith C. and Johnstone, W. (2010) Influence of the wavelength-dependence of fiber couplers on the background signal in wavelength modulation spectroscopy with RAM-nulling. Optics Express, 18 (1). pp. 267-280. ISSN 1094-4087
Ruxton, Keith C. and Chakraborty, Arup Lal and McGettrick, A.J. and Duffin, K. and Johnstone, W. and Stewart, G. (2009) Recent advance in tunable diode-laser spectroscopy with background RAM nulling for industrial applications. Proceedings of SPIE: The International Society for Optical Engineering, 7503 (750313).
Mitchell, D. and Duffin, K. and Johnstone, W. (2009) Remote methane sensor using tuneable diode laser spectroscopy (TDLS) via a 1W Raman source. Proceedings of SPIE the International Society for Optical Engineering, 7503 (750350). ISSN 0277-786X
McGettrick, A.J. and Johnstone, W. and Black, J.D. (2009) Tunable diode laser spectroscopy with wavelength modulation : calibration-free measurements of gas compositions at elevated temperatures and varying pressure. Journal of Lightwave Technology, 27 (15). pp. 3150-3161. ISSN 0733-8724
Chakraborty, Arup Lal and Ruxton, Keith C. and Johnstone, W. and Lengden, Michael and Duffin, K. (2009) Elimination of residual amplitude modulation in tunable diode laser wavelength modulation spectroscopy using an optical fiber delay line. Optics Express, 17 (12). pp. 9602-9607. ISSN 1094-4087
Mitchell, D.M. and Duffin, K. and Johnstone, W. (2009) Remote tuneable diode laser spectroscopy (TDLS) via a 1W Raman source. Proceedings of SPIE the International Society for Optical Engineering, 7356. 73560Y. ISSN 0277-786X
Duffin, K. and Johnstone, W. and McGettrick, A.J. and Moodie, D. and Stewart, G. and Thursby, G.J. and Culshaw, B. (2008) Chemical sensor networks for gas detection and environmental monitoring. Current Analytical Chemistry, 4 (4). pp. 391-402. ISSN 1573-4110
Johnstone, W. and McGettrick, A.J. and Duffin, K. and Cheung, A. and Stewart, G. (2008) Tunable diode laser spectroscopy for industrial process applications : system characterization in conventional and new approaches. IEEE Sensors Journal, 8 (7). pp. 1079-1088. ISSN 1530-437X
McGettrick, A.J. and Duffin, K. and Johnstone, W. and Stewart, G. and Moodie, D.G. (2008) Tunable diode laser spectroscopy with wavelength modulation : a phasor decomposition method for calibration-free measurements of gas concentration and pressure. Journal of Lightwave Technology, 26 (4). pp. 432-440. ISSN 0733-8724
Stewart, G. and Johnstone, W. and Arsad, N. and Duffin, K. (2008) Tunable diode and fibre laser spectroscopy in the near-IR for measurement of gas parameters. Proceedings of SPIE: The International Society for Optical Engineering, 7003. p. 700319.
Duffin, K. and McGettrick, A.J. and Johnstone, W. and Stewart, G. and Moodie, D. (2007) Tunable diode laser spectroscopy with wavelength modulation : a calibration-free approach to the recovery of absolute gas absorption line-shapes. Journal of Lightwave Technology, 25 (10). pp. 3114-3125. ISSN 0733-8724
Jenkins, C. and Brown, J.G. and Li, L. and Johnstone, W. and Uttamchandani, D.G. (2007) MEMS retro-phase-modulator for free space coherent optical communications. IEEE Journal of Selected Topics in Quantum Electronics, 13 (2). pp. 330-335. ISSN 1077-260X
Cheung, Amy and Johnstone, Walter and Moodie, David (2006) Gas detection based on optical correlation spectroscopy using a single light source. Measurement Science and Technology, 17 (5). pp. 1107-1112. ISSN 0957-0233
Shi, L. and Johnstone, W. and Andonovic, I. (2005) Experimental demonstration of a coherent optical CDMA network employing DPSK transmission. IEE Proceedings Optoelectronics, 152 (6). pp. 330-336. ISSN 1350-2433
Shi, L. and Johnstone, W. and Andonovic, I. (2005) Analysis of coherent optical CDMA networks employing DPSK transmission. IEE Proceedings Optoelectronics, 152 (6). pp. 321-329. ISSN 1350-2433
Armstrong, I. and Andonovic, I. and Kelly, A. and Bonthron, S. and Bebbington, J. and Michie, W.C. and Tombling, C. and Fasham, S. and Johnstone, W. (2005) Hybridisation platform assembly and demonstration of all optical wavelength conversion at 10Gbit/s. Journal of Lightwave Technology, 23 (5). pp. 1852-1859. ISSN 0733-8724
Jenkins, C.R. and Johnstone, W. and Uttamchandani, D.G. and Handerek, V. and Radcliffe, S. (2005) MEMS actuated spherical retroreflector for free-space optical communications. Electronics Letters, 41 (23). pp. 1278-1279. ISSN 0013-5194
Johnstone, Walter and Duffin, Kevin and Mcgettrick, Andrew James and Stewart, George and CHEUNG, Amy and Moodie, D. (2005) Tuneable diode laser spectroscopy over optical fibres for gas measurements in harsh industrial environments. Proceedings of SPIE: The International Society for Optical Engineering, 5952. p. 595206.
Stewart, George and Whitenett, Gillian and Marshall, Joanna P. and Johnstone, Walter and Culshaw, Brian and MacLean, Alistair and Mauchline, Iain S. and Moodie, David G. (2004) Remote gas analysis using fibre optic links and near infrared adsorption. Proceedings of SPIE: The International Society for Optical Engineering, 5459 (285). pp. 285-294.
MacLean, A. and Moran, C. and Johnstone, W. and Culshaw, B. and Marsh, D. and Parker, P. (2003) Detection of solvents using a distributed fibre optic sensor. Electronics Letters, 39 (17). pp. 1237-1238. ISSN 0013-5194
Stewart, G. and Culshaw, B. and Johnstone, W. and Whitenett, G.L. and Atherton, K. and McLean, A. (2003) Optical fibre sensors and networks for environmental monitoring. Management of Environmental Quality, 14 (2). pp. 181-190. ISSN 1477-7835
MacLean, Alistair and Moran, C. and Johnstone, W. and Culshaw, B. and Marsh, D. and Parker, P. (2001) Detection of hydrocarbon fuel spills using a distributed fibre optic sensor. Sensors and Actuators A: Physical, 109 (1). pp. 60-67. ISSN 0924-4247
Book Section
Zhang, Rui and Xia, Jiangnan and McCann, Hugh and Liu, Chang and Ahmed, Ihab and Pourkashanian, Mohamed and Gough, Andrew and Armstrong, Ian and Lengden, Michael and Johnstone, Walter; (2023) Miniature modular sensor for chemical species tomography with enhanced spatial resolution. In: 2023 IEEE International Conference on Imaging Systems and Techniques (IST). IEEE International Workshop on Imaging Systems and Techniques (IST) . IEEE, DNK. ISBN 9798350330830
Zhang, Congzhe and Yang, Yuanhong and Lin, Yuechuan and Tan, Yanzhen and Lengden, Michael and Humphries, Gordon and Johnstone, Walter and Lut Ho, Hoi and Jin, Wei; (2018) All-optical fiber multi-point photoacoustic spectroscopic gas sensing system. In: Proceedings 26th International Conference on Optical Fiber Sensors. Optical Society of America, CHE. ISBN 9781943580507
Bauer, Ralf and Flockhart, Gordon M. H. and Johnstone, Walter and Lengden, Michael; (2016) Trace gas sensing using DFB laser and QCL with miniaturized 3D-printed photoacoustic gas cells. In: International Conference on Fibre Optics and Photonics 2016. Optical Society of America, IND. ISBN 978-1-943580-22-4
Chighine, Andrea and Fisher, Edward and Wilson, David and Lengden, Michael and Johnstone, Walter and McCann, Hugh; (2015) An FPGA-based lock-in detection system to enable chemical species tomography using TDLAS. In: 2015 IEEE International Conference on Imaging Systems and Techniques (IST). IEEE, Piscataway, NJ, pp. 1-5. ISBN 9781479986330
Wright, Paul and McCormick, David and Ozanyan, Krikor and Johnson, Mark and Black, John and Fisher, Edward and Chighine, Andrea and Polydorides, Nick and McCann, Hugh and Feng, Yutong and Khan, Khouler and Bastock, Paul and Jia, Fuqiang and Hewak, Dan and Nilsson, Johan and Lengden, Michael and Wilson, David and Armstrong, Ian and Benoy, Thomas and Johnstone, Walter; (2015) Progress towards non-intrusive optical measurement of gas turbine exhaust species distributions. In: Aerospace Conference, 2015 IEEE. IEEE, USA, pp. 1-14. ISBN 9781479953790
Bauer, Ralf and Wilson, David and Johnstone, Walter and Lengden, Michael; (2015) MIR photoacoustic trace gas sensing using a miniaturized 3D printed gas cell. In: Advanced Photonics 2015, OSA Technical Digest. Optical Society of America. ISBN 978-1-55752-000-5
Jenkins, C.R. and Brown, J.G. and Johnstone, W. and Uttamchandani, D.G.; (2006) MEMS actuated small scale retroreflectors for free space optical communications. In: Proceedings of the IEEE/LEOS International Conference on Optical MEMS and their Applications Conference, 2005. IEEE, S384-S390. ISBN 0-7803-9278-7
Johnstone, W.; Bishnu, P. Pal., ed. (2006) Side-polished evanescently coupled optical fiber overlay devices : a review. In: Guided wave optical components and devices. Academic Press, pp. 225-232. ISBN 9780120884810
Walsh, D.J. and Moodie, D. and Mauchline, I.S. and Conner, S. and Johnstone, W. and Culshaw, B.; (2005) Student laboratory experiments exploring optical fibre communications, systems eye diagrams and bit error rates. In: Proceedings of SPIE Opto-Ireland 2005. SPIE, IRL, p. 605. ISBN 0819458120
Conference or Workshop Item
Archilla, V. and Aragón, G. and Wright, P. and Ozanyan, K. and Black, J. and Polydorides, N. and McCann, H. and Lengden, M. and Burns, I. and Johnstone, W. and Polo, V. and Beltran, M. and Mauchline, I. and Walsh, D. and Johnson, M. (2018) CIDAR : combustion species imaging diagnostics for aero-engine research. In: Aerosol Technology, 2018-06-18 - 2018-06-20.
Archilla, V. and Aragón, G. and Wright, P. and Ozanyan, K. and Black, J. and Lengden, M. and Burns, I. and Johnstone, W. and Polo, V. and Beltran, M. and Johnson, M. (2018) CIDAR project - development of a non-intrusive capability for aircraft engine measurements. In: Aerosol Technology, 2018-06-18 - 2018-06-20.
Wilson, David and Humphries, Gordon Samuel and Benoy, Thomas and Lengden, Michael and Johnstone, Walter and Tsekenis, Alex and Fisher, Edward and Chigine, Andrea and McCann, Hugh and Feng, Yutong and Nilsson, Johan and Wright, Paul and McCormick, David and Ozanyan, Krikor and Archilla Prat, Victor and Johnson, Mark and Black, John (2016) Working towards cleaner air travel : the technology behind the FLITES project. In: FLAIR 2016 - Field Laser Applications in Industry and Research, 2016-09-12 - 2016-09-16.
Lengden, Michael and Bauer, Ralf and Johnstone, Walter (2015) Gas concentration measurements using photoacoustic sensors for industrial solid oxide fuel cell process control. In: ECS Conference on Electrochemical Energy Conversion & Storage with SOFC X1V, 2015-06-26 - 2015-07-31.
Lengden, Michael and Wilson, David and Armstrong, Ian and Benoy, Thomas and Johnstone, Walter (2015) Fibre laser imaging of gas turbine exhaust species – a review of CO2 aero engine imaging. In: Advanced Photonics, 2015-06-27 - 2015-07-01.
Bauer, Ralf M. and Wilson, David and Johnstone, Walter and Lengden, Michael (2015) MIR photoacoustic trace gas sensing using a miniaturized 3D printed gas cell. In: Advanced Photonics, 2015-06-27 - 2015-07-01.
Bauer, Ralf and Stewart, George and Johnstone, Walter and Lengden, Michael (2014) Photoacoustic trace gas sensing using a miniature 3D printed gas cell. In: Photon14, 2014-09-01 - 2014-09-04, Imperial College London.
Feng, Yutong and Nilsson, Johan and Jain, Saurabh and May-Smith, Timothy C. and Sahu, Jayanta K. and Jia, Fuqiang and Benoy, Thomas and Wilson, David and Lengden, Michael and Johnstone, Walter (2014) LD-seeded thulium-doped fibre amplifier for CO2 measurements at 2 µm. In: Europhoton 2014, 2014-08-24 - 2014-08-29.
Wilson, David and Armstrong, Ian and Lengden, Michael and Johnstone, Walter (2014) In-situ measurement of combustion produced CO2 in the 2μm region, within a jet engine exhaust plume. In: FLAIR 2014 - Field Laser Applications in Industry and Research, 2014-05-05 - 2014-05-09.
Benoy, Thomas and Lengden, Michael and Armstrong, Ian and Wilson, David and Stewart, George and Johnstone, Walter (2014) Near IR tunable diode laser spectroscopy for aero engine research. In: FLAIR 2014 - Field Laser Applications in Industry and Research, 2014-05-05 - 2014-05-09.
Bauer, Ralf and Stewart, George and Johnstone, Walter and Lengden, Michael (2014) A miniaturised 3D printed resonant photoacoustic cell for trace gas sensing. In: FLAIR 2014 - Field Laser Applications in Industry and Research, 2014-05-05 - 2014-05-09.
Bain, James and Lengden, Michael and Armstrong, Ian and Stewart, George and Johnstone, Walter (2013) Development of tunable diode laser spectroscopy instrumentation for gas species measurements in harsh environments. In: Applied Industrial Optics: Spectroscopy, Imaging, and Metrology, 2013-06-23 - 2013-06-27, Virginia.
Lengden, Michael and Armstrong, Ian and Bain, James and Johnstone, Walter (2012) Measurement of key species in gas turbine engine exhaust plumes. In: Institute of Physics - Delivering Future Combustion Technologies Meeting, 2012-10-23 - 2012-10-23.
Bain, James and Black, John and Lengden, Michael and Johnstone, Walter (2012) Development of tunable diode laser spectroscopy sensor systems for line-of-sight measurement of water vapour in aero engine exhaust plumes. In: PHOTON12, 2011-03-31.
Michie, Walter and Johnstone, Walter and Andonovic, Ivan and Murphy, Eoin and White, Henry and Kelly, Anthony (2011) Semiconductor optical amplifiers in avionics. In: Avionics, Fiber- Optics and Photonics Technology Conference (AVFOP), 2011 IEEE, 2011-10-04 - 2011-10-06.
Lengden, Michael and Johnstone, Walter (2011) Gas composition measurements for fundamental research and process control on a 15kW solid oxide fuel cell. In: Field Laser Applications in Industry and Research, 2011-09-13 - 2011-09-17.
Bain, James and Lengden, Michael and Black, John and Johnstone, Walter (2011) Measurement of aeroengine intake gas temperature using TDLS of atmospheric water vapour. In: Field Laser Applications in Industry and Research, 2011-09-13 - 2011-09-17.
Bain, James Roderic Peter and Lengden, Michael and Stewart, George and Black, John and Johnstone, Walter (2011) Development of a TDLS-based ambient water vapour sensor for aeroengine intake temperature determination. In: 8th International Conference on Tunable Diode Laser Spectroscopy, 2011-07-11 - 2011-07-15. (Unpublished)
Lengden, Michael and Johnstone, Walter and Bain, James Roderic Peter and Milne, Laura (2011) High temperature investigations of methane for the calculation of the temperature dependence of spectral parameters. In: 8th International Conference on Tunable Diode Laser Spectroscopy, 2011-07-11 - 2011-07-15. (Unpublished)
Bain, James and Lengden, Michael and Stewart, George and Johnstone, Walter (2011) Tunable diode laser spectroscopy for process control and diagnostics in industrial systems. In: 2nd Annual SU2P symposium, 2011, 2011-03-28.
Proudfoot, A.D. and Michie, C. and Johnstone, W. and White, H.J. (2010) Power requirements and operation of amplified optical networks for future aerospace applications. In: IEEE AVFOP Conference, 2010-01-01.
Stewart, George and Ruxton, Keith Crawford and Chakraborty, Arup and Johnstone, Walter (2010) Tunable diode laser spectroscopy with wavelength modulation : an overview of current techniques and motivations. In: IoP Photonics 10 Conference, 2010-08-23 - 2010-08-26.
Lengden, Michael and Johnstone, W. and Cunningham, Robert (2010) In-situ, real time gas composition measurements for SOFC's using laser spectroscopy. In: European Fuel Cell Forum 2010, 2010-06-29 - 2010-07-02. (Unpublished)
Proudfoot, A.D. and Michie, C. and Johnstone, W. and White, H.J. (2010) The operation and power budget of amplified optical networks for aerospace applications. In: FOHEC Conference, 2010-01-01. (Unpublished)
Culshaw, Brian and Johnstone, W. and Stewart, G. and Duffin, K. and Mauchline, Iain S. and Walsh, Douglas (2009) Gas sensing based on optical fibre coupled diode laser spectroscopy : a new approach to sensor systems for safety monitoring. In: 9th IMVC Mine Ventilation Conference, 2009-11-10.
Mitchell, D.M. and Duffin, K. and Johnstone, W. (2009) Remote methane sensor using tuneable diode laser spectroscopy (TDLS) via a 1W Raman source. In: 20th International Conference on Optical Fibre Sensors, 2009-10-05.
Bain, J.R.P. and Stewart, G. and Duffin, K. and Lengden, M. and Ruxton, K.C. and Johnstone, W. (2009) Recovery of absolute gas absorption lineshapes using TDLS at arbitrary modulation indices. In: UNSPECIFIED.
Bain, J.R.P. and Stewart, G. and Duffin, K. and Lengden, M. and Ruxton, K.C. and Johnstone, W. (2009) Recovery of gas absorption lineshapes using TDLS at arbitrary modulation indices. In: International Conference on Field Laser Applications in Industry and Research, 2009-09-06 - 2009-09-11, Hotel am Badersee.
Mitchell, D.M. and Duffin, K. and Johnstone, W. (2009) Remote methane sensor using Tunable Diode Laser Spectroscopy (TDLS) via a 1W Raman So. In: 20th International Conference on Optical Fibre Sensors, 2009-10-05.
Chakraborty, A. and Ruxton, K.C. and Johnstone, W. (2009) Tunable diode laser spectroscopy with RAM nulling - current status and future possibilities. In: International Conference on Field Laser Applications in Industry and Research, 2009-09-06 - 2009-09-11, Hotel am Badersee. (Unpublished)
Lengden, M. and Bain, J.R.P. and Armstrong, I. and Johnstone, W. (2009) Two gas spectrometers for the investigation of gas absorption parameters at elevated temperatures and pressures. In: International Conference on Field Laser Applications in Industry and Research, 2009-09-06 - 2009-09-11, Hotel am Badersee.
Ruxton, K.C. and Chakraborty, A. and McGettrick, A.J. and Duffin, K. and Johnstone, W. and Stewart, G. (2009) Diode laser spectroscopy using a calibration free phasor decomposition approach with RAM nulling. In: 7th International Conference on Tunable Diode Laser Spectroscopy, 2009-07-13 - 2009-07-17.
Lengden, M. and Johnstone, W. and Bain, J.R.P. and Stewart, G. and Armstrong, I. (2009) Preliminary gas composition investigations at elevated temperatures and pressures using calibration-free tDLS with the residual amplitude modulation technique. In: 7th International Conference on Tunable Diode Laser Spectroscopy, 2009-07-13 - 2009-07-17.
Mitchell, D.M. and Duffin, K. and Johnstone, W. (2009) Remote methane sensor using raman amplified open path TDLS. In: 7th International Conference on Tunable Diode Laser Spectroscopy, 2009-07-13 - 2009-07-17.
Armstrong, I. and Chakraborty, A. and Ruxton, K.C. and Johnstone, W. (2009) An investigation of TDLS modulation schemes as applied to the Mid-IR spectral region by difference frequency generation in PPLN. In: 7th International Conference on Tunable Diode Laser Spectroscopy, 2009-07-13 - 2009-07-17. (Unpublished)
Chakraborty, Arup Lal and Ruxton, Keith C. and Johnstone, W. and Lengden, Michael and Duffin, K. (2009) Elimination of residual amplitude modulation in TDLS-WMS. In: Conference on Lasers and Electro-Optics/ European Quantum Electronics Conference (CLEO Europe/EQEC-2009), 2009-06-14 - 2009-06-19.
Ruxton, Keith C. and Chakraborty, Arup Lal and McGettrick, A.J. and Duffin, K. and Johnstone, W. and Stewart, G. (2009) Diode laser spectroscopy using a calibration free phasor decomposition approach to RAM nulling. In: 7th International Conference on Tunable Diode Laser Spectroscopy, 2009-07-13 - 2009-07-17.
Proudfoot, A.D. and Michie, C. and Johnstone, W. and White, H.J. (2009) Modelling the power budget of amplified optical networks for future aerospace applications. In: IEEE AVFOP Conference, 2009-01-01. (Unpublished)
Mitchell, D. and Duffin, K. and Johnstone, W. (2009) Remote methane sensor using TDLS via a high power Raman amplified source. In: International Conference on Field Laser Applications in Industry and Research, 2009-09-06 - 2009-09-11, Hotel am Badersee. (Unpublished)
Johnstone, W. and Duffin, K. and Mitchell, David Michael (2008) Remote gas detection using tunable diode laser spectroscopy with high power rare earth and raman fibre amplifiers. In: Photonics 2008: International Conference on Fiber Optics and Photonics, 2008-12-13 - 2008-12-17. (Unpublished)
McGettrick, A.J. and Johnstone, W. and Duffin, K. and Stewart, G. (2008) Calibration free gas composition measurements for industrial process control using a phasor decomposition approach to tunable diode laser spectroscopy. In: Photon 08, 2008-08-25 - 2008-08-28. (Unpublished)
Johnstone, W. and McGettrick, A.J. and Duffin, K. and Stewart, G. (2008) Calibration free, optical measurements of gas composition for industrial process control in harsh environments. In: Fifth International Conference on Condition Monitoring and Machine Failure Prevention Technologies, 2008-07-15 - 2008-07-18. (Unpublished)
Mauchline, I. and Walsh, D. and Moodie, D. and Conner, S. and Johnstone, W. and Culshaw, B. (2007) Practical introduction to optical WDM components and systems in student teaching laboratories. In: 10th International Conference on Education and Training in Optics and Photonics, 2007-06-03 - 2007-06-05.
Duffin, K. and McGettrick, A.D. and Johnstone, W. and Stewart, G. (2007) An alternative approach to wavelength modulation spectroscopy for absolute measurements of gas parameters in industrial processes. In: Chemical and Biological Sensors for Industrial and Environmental Monitoring III, 2006-07-12.
Walsh, D.J. and Moodie, D. and Mauchline, I.S. and Conner, S. and Johnstone, W. and Culshaw, B. (2005) Practical bit error rate measurements on fibre optic communications links in student teaching laboratories. In: Education and Training in Optics and Photonics 2005, 2005-10-24 - 2005-10-27.
Cheung, A. and Johnstone, W. and Moodie, D. (2005) Detection of acetylene gas using optical correlation spectroscopy. In: 17th International Conference on Optical Fibre Sensors, 2005-05-23 - 2005-05-27.
Cheung, A. and Culshaw, B. and Duffin, K. and Johnstone, W. and McGettrick, A.D. and Mauchline, I.S. and Moodie, D. (2005) Gas spectroscopy in the near infrared optical fibre network. In: Australasian Conference on Optics, Lasers and Spectroscopy, 2005-12-08.
Jenkins, C.R. and Johnstone, W. and Uttamchandani, D.G. and Handerek, V. and Radcliffe, S. (2005) Microactuated small scale retroreflector for free space optical communications. In: IEEE/LEOS International Conference on Optical MEMS and Their Applications Conference, 2005, 2005-08-01.
Cheung, A. and Johnstone, W. and Moodie, D. (2005) Recent advances in gas detection using optical correlation spectroscopy. In: Optical Fibers: Applications, 2005-09-01.
Walsh, D.J. and Moodie, D. and Mauchline, I.S. and Johnstone, Walter and Stewart, George (2003) OptoSci educator kits - an immediate solution to photonics teaching laboratories. In: Education and Training in Optics and Photonics (ETOP) 2003, 2003-10-06.
Stewart, G. and Whitenett, G.L. and Atherton, K. and Culshaw, B. and Johnstone, W. (2002) Optical fibre sensors for environmental monitoring of trace gases. In: 19th Congress of the International-Commission-for-Optics, 2002-08-25 - 2002-08-30.
Culshaw, B. and Johnstone, W. and McLean, A. and Mauchline, I.S. and Moodie, D. and Stewart, G. (2002) Large scale multiplexing a point sensor for methane gas detection. In: 15th Optical Fiber Sensors Conference, 2002-05-06 - 2002-05-10.
Maclean, A. and Moran, C. and Johnstone, W. and Culshaw, B. and Marsh, D. and Andrews, G.M. (2001) A distributed fibre optic sensor for liquid hydrocarbon detection. In: Smart Structures and Materials 2001 Conference, 2001-03-05 - 2001-03-08.