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Research Output 2001 2019

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Article
2018

A new RAM normalized 1f-WMS technique for the measurement of gas parameters in harsh environments and a comparison with 2f/1f

Upadhyay, A., Lengden, M., Wilson, D., Humphries, G. S., Crayford, A. P., Pugh, D. G., Johnson, M. P., Stewart, G. & Johnstone, W., 27 Nov 2018, In : IEEE Photonics Journal. 10, 6, 12 p., 6804611.

Research output: Contribution to journalArticle

Open Access
File
Random access storage
Modulation
Spectroscopy
modulation
Wavelength
2017
7 Citations (Scopus)
Open Access
File
Distributed feedback lasers
Surface emitting lasers
Modulation
Spectroscopy
Calibration
3 Citations (Scopus)

Constrained models for optical absorption tomography

Polydorides, N., Tsekenis, A., Fisher, E., Chigine, A., McCann, H., Dimiccoli, L., Wright, P., Lengden, M., Benoy, T., Wilson, D., Humphries, G. & Johnstone, W., 23 Oct 2017, In : Applied Optics. 57, 7, p. B1-B9 9 p.

Research output: Contribution to journalArticle

Open Access
File
optical absorption
tomography
projection
pencil beams
image reconstruction
1 Citation (Scopus)

Measurement of CO2 concentration and temperature in an aero engine exhaust plume using wavelength modulation spectroscopy

Benoy, T., Wilson, D., Lengden, M., Armstrong, I., Stewart, G. & Johnstone, W., 1 Oct 2017, In : IEEE Sensors Journal. 17, 19, p. 6409-6417 9 p.

Research output: Contribution to journalArticle

Open Access
File
Exhaust systems (engine)
plumes
engines
Modulation
Spectroscopy
2016
6 Citations (Scopus)
Open Access
File
Laser spectroscopy
Amplitude modulation
laser spectroscopy
line shape
Semiconductor lasers
5 Citations (Scopus)
Open Access
File
Distributed feedback lasers
distributed feedback lasers
line shape
recovery
Modulation
2015
11 Citations (Scopus)

Miniaturized photoacoustic trace gas sensing using a raman fiber amplifier

Bauer, R., Legg, T., Mitchell, D., Flockhart, G. M. H., Stewart, G., Johnstone, W. & Lengden, M., 15 Sep 2015, In : Journal of Lightwave Technology. 33, 18, p. 3773-3780 9 p.

Research output: Contribution to journalArticle

Open Access
File
Fiber amplifiers
Photoacoustic effect
Photoacoustic spectroscopy
Seed
Stimulated Brillouin scattering
2014
2 Citations (Scopus)
Open Access
File
Passive optical networks
power loss
transmitters
division
aircraft
2013
8 Citations (Scopus)

Tunable diode laser based concentration measurements of water vapour and methane on a solid oxide fuel cell

Lengden, M., Cunningham, R. & Johnstone, W., 1 May 2013, In : Journal of Lightwave Technology. 31, 9, p. 1354 - 1359 7 p.

Research output: Contribution to journalArticle

solid oxide fuel cells
Solid oxide fuel cells (SOFC)
Water vapor
Semiconductor lasers
water vapor
2011
9 Citations (Scopus)

Intra-cavity spectroscopy using amplified spontaneous emission in fiber lasers

Arsad, N., Min, L., Stewart, G. & Johnstone, W., 1 Mar 2011, In : Journal of Lightwave Technology. 29, 5, p. 782-788 7 p.

Research output: Contribution to journalArticle

Open Access
File
spontaneous emission
fiber lasers
cavities
gases
spectroscopy
36 Citations (Scopus)
laser spectroscopy
line shape
recovery
diodes
modulation
44 Citations (Scopus)

Recovery of absolute gas absorption line shapes using tuneable diode laser spectroscopy with wavelength modulation- part 1: theoretical analysis

Stewart, G., Johnstone, W., Bain, J. R. P., Ruxton, K. C. & Duffin, K., 15 Mar 2011, In : Journal of Lightwave Technology. 29, 6, p. 811-821 11 p.

Research output: Contribution to journalArticle

Gas absorption
Laser spectroscopy
laser spectroscopy
line shape
Semiconductor lasers
2010
14 Citations (Scopus)

Detection of CH4 in the mid-IR using difference frequency generation with tunable diode laser spectroscopy

Armstrong, I., Johnstone, W., Duffin, K., Lengden, M., Chakraborty, A. L. & Ruxton, K. C., 15 May 2010, In : Journal of Lightwave Technology. 28, 10, p. 1435-1442 8 p.

Research output: Contribution to journalArticle

laser spectroscopy
diodes
methane
wavelengths
11 Citations (Scopus)

Influence of the wavelength-dependence of fiber couplers on the background signal in wavelength modulation spectroscopy with RAM-nulling

Chakraborty, A. L., Ruxton, K. C. & Johnstone, W., 4 Jan 2010, In : Optics Express. 18, 1, p. 267-280 14 p.

Research output: Contribution to journalArticle

couplers
modulation
fibers
elimination
wavelengths
9 Citations (Scopus)
Open Access
File
Near-infrared Spectroscopy
Near infrared spectroscopy
Gases
infrared spectroscopy
Fiber
Gas fuel measurement
Elimination
Spectroscopy
elimination
Modulation
15 Citations (Scopus)

Suppression of intensity modulation contributions to signals in second harmonic wavelength modulation spectroscopy

Chakraborty, A. L., Ruxton, K. C. & Johnstone, W., 8 Jul 2010, In : Optics Letters. 35, 14, p. 2400-2402 2 p.

Research output: Contribution to journalArticle

retarding
harmonics
modulation
wavelengths
spectroscopy
34 Citations (Scopus)

Tunable diode laser spectroscopy with wavelength modulation: elimination of residual amplitude modulation in a phasor decomposition approach

Ruxton, K. C., Chakraborty, A. L., Johnstone, W., Lengden, M., Stewart, G. & Duffin, K., 21 Sep 2010, In : Sensors and Actuators B: Chemical. 150, 1, p. 367-375 9 p.

Research output: Contribution to journalArticle

Laser spectroscopy
Amplitude modulation
laser spectroscopy
Semiconductor lasers
elimination
2009
39 Citations (Scopus)

Elimination of residual amplitude modulation in tunable diode laser wavelength modulation spectroscopy using an optical fiber delay line

Chakraborty, A. L., Ruxton, K. C., Johnstone, W., Lengden, M. & Duffin, K., Jun 2009, In : Optics Express. 17, 12, p. 9602-9607 6 p.

Research output: Contribution to journalArticle

delay lines
elimination
optical fibers
semiconductor lasers
modulation
4 Citations (Scopus)

Recent advance in tunable diode-laser spectroscopy with background RAM nulling for industrial applications

Ruxton, K. C., Chakraborty, A. L., McGettrick, A. J., Duffin, K., Johnstone, W. & Stewart, G., Oct 2009, In : Proceedings of SPIE: The International Society for Optical Engineering. 7503, 750313

Research output: Contribution to journalArticle

Nulling
Laser Spectroscopy
Tunable Laser
Amplitude Modulation
Laser spectroscopy
6 Citations (Scopus)
Laser Spectroscopy
Laser spectroscopy
Diode Laser
Methane
Raman

Remote tuneable diode laser spectroscopy (TDLS) via a 1W Raman source

Mitchell, D. M., Duffin, K. & Johnstone, W., 18 May 2009, In : Proceedings of SPIE the International Society for Optical Engineering. 7356, p. 73560Y

Research output: Contribution to journalArticle

Laser Spectroscopy
Laser spectroscopy
Diode Laser
Raman
laser spectroscopy
18 Citations (Scopus)
gas composition
laser spectroscopy
line shape
diodes
operating temperature
2008
8 Citations (Scopus)

Chemical sensor networks for gas detection and environmental monitoring

Duffin, K., Johnstone, W., McGettrick, A. J., Moodie, D., Stewart, G., Thursby, G. J. & Culshaw, B., Oct 2008, In : Current Analytical Chemistry. 4, 4, p. 391-402 11 p.

Research output: Contribution to journalArticle

Chemical sensors
Sensor networks
Gases
Semiconductor lasers
Monitoring
5 Citations (Scopus)
Laser Spectroscopy
Tunable Laser
Laser spectroscopy
Diode Laser
Fiber Laser
37 Citations (Scopus)

Tunable diode laser spectroscopy for industrial process applications: system characterization in conventional and new approaches

Johnstone, W., McGettrick, A. J., Duffin, K., Cheung, A. & Stewart, G., Jul 2008, In : IEEE Sensors Journal. 8, 7, p. 1079-1088 10 p.

Research output: Contribution to journalArticle

Laser spectroscopy
laser spectroscopy
Semiconductor lasers
diodes
Amplitude modulation
54 Citations (Scopus)

Tunable diode laser spectroscopy with wavelength modulation: a phasor decomposition method for calibration-free measurements of gas concentration and pressure

McGettrick, A. J., Duffin, K., Johnstone, W., Stewart, G. & Moodie, D. G., 15 Feb 2008, In : Journal of Lightwave Technology. 26, 4, p. 432-440 9 p.

Research output: Contribution to journalArticle

laser spectroscopy
diodes
modulation
decomposition
gases
2007
6 Citations (Scopus)

MEMS retro-phase-modulator for free space coherent optical communications

Jenkins, C., Brown, J. G., Li, L., Johnstone, W. & Uttamchandani, D. G., Mar 2007, In : IEEE Journal of Selected Topics in Quantum Electronics. 13, 2, p. 330-335 5 p.

Research output: Contribution to journalArticle

Optical communication
Modulators
microelectromechanical systems
MEMS
optical communication
117 Citations (Scopus)

Tunable diode laser spectroscopy with wavelength modulation: a calibration-free approach to the recovery of absolute gas absorption line-shapes

Duffin, K., McGettrick, A. J., Johnstone, W., Stewart, G. & Moodie, D., Oct 2007, In : Journal of Lightwave Technology. 25, 10, p. 3114-3125 11 p.

Research output: Contribution to journalArticle

laser spectroscopy
line shape
recovery
diodes
modulation
2006
7 Citations (Scopus)

Gas detection based on optical correlation spectroscopy using a single light source

Cheung, A., Johnstone, W. & Moodie, D., 2006, In : Measurement Science and Technology. 17, 5, p. 1107-1112 5 p.

Research output: Contribution to journalArticle

Optical correlation
Semiconductor optical amplifiers
light amplifiers
Light sources
Spectroscopy
2005
1 Citation (Scopus)

Analysis of coherent optical CDMA networks employing DPSK transmission

Shi, L., Johnstone, W. & Andonovic, I., 2005, In : IEE Proceedings Optoelectronics. 152, 6, p. 321-329 8 p.

Research output: Contribution to journalArticle

phase shift keying
code division multiple access
Phase shift keying
Code division multiple access
Network performance

Experimental demonstration of a coherent optical CDMA network employing DPSK transmission

Shi, L., Johnstone, W. & Andonovic, I., Dec 2005, In : IEE Proceedings Optoelectronics. 152, 6, p. 330-336 6 p.

Research output: Contribution to journalArticle

code division multiple access
Code division multiple access
Demonstrations
phase shift keying
Phase shift keying
6 Citations (Scopus)

Hybridisation platform assembly and demonstration of all optical wavelength conversion at 10Gbit/s

Armstrong, I., Andonovic, I., Kelly, A., Bonthron, S., Bebbington, J., Michie, W. C., Tombling, C., Fasham, S. & Johnstone, W., 2005, In : Journal of Lightwave Technology. 23, 5, p. 1852-1859 7 p.

Research output: Contribution to journalArticle

Mach-Zehnder interferometers
penalties
light amplifiers
transfer functions
converters
14 Citations (Scopus)

MEMS actuated spherical retroreflector for free-space optical communications

Jenkins, C. R., Johnstone, W., Uttamchandani, D. G., Handerek, V. & Radcliffe, S., 2005, In : Electronics Letters. 41, 23, p. 1278-1279 1 p.

Research output: Contribution to journalArticle

Optical communication
Modulators
MEMS
MOEMS
Frequency response

Tuneable diode laser spectroscopy over optical fibres for gas measurements in harsh industrial environments

Johnstone, W., Duffin, K., Mcgettrick, A. J., Stewart, G., CHEUNG, A. & Moodie, D., 2005, In : Proceedings of SPIE: The International Society for Optical Engineering. 5952, p. 595206

Research output: Contribution to journalArticle

Laser Spectroscopy
Gas fuel measurement
Laser spectroscopy
Diode Laser
laser spectroscopy
2003
4 Citations (Scopus)

Detection of solvents using a distributed fibre optic sensor

MacLean, A., Moran, C., Johnstone, W., Culshaw, B., Marsh, D. & Parker, P., 21 Aug 2003, In : Electronics Letters. 39, 17, p. 1237-1238 2 p.

Research output: Contribution to journalArticle

Open Access
File
Fiber optic sensors
Sensors
Hazardous materials spills
Liquids
15 Citations (Scopus)

Optical fibre sensors and networks for environmental monitoring

Stewart, G., Culshaw, B., Johnstone, W., Whitenett, G. L., Atherton, K. & McLean, A., 2003, In : Management of Environmental Quality. 14, 2, p. 181-190 9 p.

Research output: Contribution to journalArticle

Optical Fibers
Environmental Monitoring
fiber optics
Fiber optic sensors
hydrogen sulfide
2001
55 Citations (Scopus)

Detection of hydrocarbon fuel spills using a distributed fibre optic sensor

MacLean, A., Moran, C., Johnstone, W., Culshaw, B., Marsh, D. & Parker, P., 2001, In : Sensors and Actuators A: Physical. 109, 1, p. 60-67 7 p.

Research output: Contribution to journalArticle

hydrocarbon fuels
Fiber optic sensors
Hazardous materials spills
Hydrocarbons
fiber optics