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19982021
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Research Output 1998 2018

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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
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
3 Citations (Scopus)

Detection of nitrous oxide (N2O) at sub-ppmv using intracavity absorption spectroscopy

Valiunas, J. K., Stewart, G. & Das, G., 1 Feb 2016, In : IEEE Photonics Technology Letters. 28, 3, p. 359-362 4 p.

Research output: Contribution to journalArticle

Open Access
File
nitrous oxides
Nitrous Oxide
Fiber lasers
Absorption spectroscopy
fiber lasers
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
10 Citations (Scopus)
Open Access
File
attenuators
Single mode fibers
Evanescent fields
fibers
Fibers
2014
1 Citation (Scopus)
Open Access
File
attenuators
fiber optics
optical fibers
fibers
miniaturization
2011
18 Citations (Scopus)

Absorption line profile recovery based on residual amplitude modulation and first harmonic integration methods in photoacoustic gas sensing

Li, L., Arsad, N., Stewart, G., Thursby, G. J., Culshaw, B. & Wang, Y., 1 Jan 2011, In : Optics Communications. 284, 1, p. 312-316 5 p.

Research output: Contribution to journalArticle

Photoacoustic effect
Amplitude modulation
Photoacoustic spectroscopy
Gases
recovery

Absorption line profile recovery based on TDLS and MEMS micro-mirror for photoacoustic gas sensing

Li, L., Arshad, N., Stewart, G., Thursby, G., Uttamchandani, D., Culshaw, B. & Yang, YD., 1 Jul 2011, In : Spectroscopy and Spectral Analysis. 31, 7, p. 1814-1818 5 p.

Research output: Contribution to journalArticle

Acetylene
Erbium doped fiber amplifiers
Laser spectroscopy
Photoacoustic effect
laser spectroscopy
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
9 Citations (Scopus)
Open Access
File
Near-infrared Spectroscopy
Near infrared spectroscopy
Gases
infrared spectroscopy
Fiber
3 Citations (Scopus)
Photoacoustic spectroscopy
Laser Spectroscopy
Acetylene
Tunable Laser
photoacoustic 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
21 Citations (Scopus)

In-plane integration of polymer microfluidic channels with optical waveguides - a preliminary investigation

Sheridan, A. K., Stewart, G., Ur-Reyman, H., Suyal, N. & Uttamchandani, D. G., Dec 2009, In : IEEE Sensors Journal. 9, 12, p. 1627-1632 6 p.

Research output: Contribution to journalArticle

Optical waveguides
Microfluidics
optical waveguides
Lab-on-a-chip
Waveguides
27 Citations (Scopus)

Multiwavelength operation of erbium-doped fiber lasers by periodic filtering and phase modulation

Mirza, M. A. & Stewart, G., 15 Apr 2009, In : Journal of Lightwave Technology. 27, 8, p. 1034-1044 11 p.

Research output: Contribution to journalArticle

Open Access
File
phase modulation
erbium
fiber lasers
modulation
fibers
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
3 Citations (Scopus)
gas spectroscopy
Erbium
Saturable Absorber
Erbium-doped Fiber
Saturable absorbers
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
39 Citations (Scopus)

Theory and design of a simple tunable sagnac loop filter for multi-wavelength fibre lasers

Mirza, M. A. & Stewart, G., Oct 2008, In : Applied Optics. 47, 29, p. 5242-5252 10 p.

Research output: Contribution to journalArticle

fiber lasers
filters
birefringence
wavelengths
output
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
24 Citations (Scopus)

Investigation of the dynamic response of erbium fibre lasers with potential application for sensors

Stewart, G., Whitenett, G., Vijayraghavan, K. & Sridaran, S., Jul 2007, In : Journal of Lightwave Technology. 25, 7, p. 1786-1796 10 p.

Research output: Contribution to journalArticle

dynamic response
erbium
fiber lasers
sensors
transient response
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
102 Citations (Scopus)

Design of a portable optical sensor for methane gas detection

Massie, C., Stewart, G., McGregor, G. & Gilchrist, J. R., Feb 2006, In : Sensors and Actuators B: Chemical. 113, 2, p. 830-836 6 p.

Research output: Contribution to journalArticle

Methane
Optical sensors
optical measuring instruments
methane
Gases
32 Citations (Scopus)

Design of a tuneable L-Band multi-wavelength laser system for application to gas spectroscopy

Marshall, J., Stewart, G. & Whitenett, G., Apr 2006, In : Measurement Science and Technology. 17, 4, p. 1023-1031 8 p.

Research output: Contribution to journalArticle

gas spectroscopy
ultrahigh frequencies
Spectroscopy
Wavelength
Laser
135 Citations (Scopus)

Stable single-mode operation of a narrow-linewidth, linear polarization erbium fibre ring laser using a saturable absorber

Meng, Z., Stewart, G. & Whitenett, G. L., 2006, In : Journal of Lightwave Technology. 24, 5, p. 2179-2183 4 p.

Research output: Contribution to journalArticle

ring lasers
linear polarization
erbium
fiber lasers
absorbers
2005
34 Citations (Scopus)

Phase noise characteristics of a diode-pumped Nd:YAG laser in an unbalanced fiber-optic interferometer

Meng, Z., Hu, Y., Xiong, S., Stewart, G., Whitenett, G. L. & Culshaw, B., 2005, In : Applied Optics. 44, 17, p. 3425-3428 3 p.

Research output: Contribution to journalArticle

YAG lasers
fiber optics
interferometers
diodes
optical paths

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
2004

Amplifier enhances ring-down spectroscopy

Hitz, B. & Stewart, G., 2004, In : Photonics Spectra. 38, 5, p. 124-125 2 p.

Research output: Contribution to journalArticle

Open Access
File
Fiber optics
reflectors
Optical fibers
Q factors
Resonators
54 Citations (Scopus)

Cavity enhanced spectroscopy in fibre cavities

Stewart, G., Atherton, K. & Culshaw, B., 2004, In : Optics Letters. 29, 5, p. 442-444 2 p.

Research output: Contribution to journalArticle

cavities
fibers
downtime
spectroscopy
rings
34 Citations (Scopus)

Development of fibre laser systems for ring-down and intracavity gas spectroscopy in the near-IR

Stewart, G., Shields, P. & Culshaw, B., 2004, In : Measurement Science and Technology. 15, 8, p. 1621-1628 7 p.

Research output: Contribution to journalArticle

gas spectroscopy
Fiber Laser
Fiber lasers
fiber lasers
Spectroscopy
74 Citations (Scopus)

Investigation of a tuneable mode-locked fibre laser for application to multi-point gas spectroscopy

Whitenett, G. L., Stewart, G., Yu, H. & Culshaw, B., Mar 2004, In : Journal of Lightwave Technology. 22, 3, p. 813-819 6 p.

Research output: Contribution to journalArticle

gas spectroscopy
fiber lasers
tuning
gratings
sensors
29 Citations (Scopus)

Investigation of erbium-doped fiber laser intra-cavity absorption sensor for gas detection

Zhang, Y., Zhang, M., Jin, W., Ho, H. L., Demokan, M. S., Culshaw, B. & Stewart, G., 2004, In : Optics Communications. 232, 1-6, p. 295-301 6 p.

Research output: Contribution to journalArticle

Erbium
Fiber lasers
erbium
fiber lasers
Gases
2003
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
2002
3 Citations (Scopus)

Fibre optic gas sensing using absorption spectroscopy

Jin, W., Ho, H., Stewart, G. & Culshaw, B., Dec 2002, In : Trends in Applied Spectroscopy. 4, p. 155-163 8 p.

Research output: Contribution to journalArticle

fiber optics
absorption spectroscopy
sensors
optical fibers
gases
34 Citations (Scopus)

Novel intra-cavity sensing network based on mode-locked fibre laser

Zhang, Y., Jin, W., Yu, H. B., Zhang, M., Liao, Y. B., Ho, H. L., Demokan, M. S., Stewart, G., Culshaw, B. & Li, Y. H., Sep 2002, In : IEEE Photonics Technology Letters. 14, 9, p. 1336-1338 2 p.

Research output: Contribution to journalArticle

Mode-locked fiber lasers
fiber lasers
Laser mode locking
cavities
sensors
2001
158 Citations (Scopus)

Investigation of optical fibre amplifier loop for intracavity and ring down cavity loss measurements

Stewart, G., Atherton, K., Yu, H. & Culshaw, B., 2001, In : Measurement Science and Technology. 12, 7, p. 843-849 6 p.

Research output: Contribution to journalArticle

Optical Amplifier
Fiber Amplifier
Fiber amplifiers
Optical Fiber
Cavity
19 Citations (Scopus)

Multiplexing of optical fibre gas sensors with an FMCW technique

Yu, H. B., Jin, W., Ho, H. L., Chan, K. C., Chan, C. C., Demokan, M. S., Stewart, G., Culshaw, B. & Liao, Y. B., 1 Mar 2001, In : Applied Optics. 40, 7, p. 1011-1020 9 p.

Research output: Contribution to journalArticle

multiplexing
optical fibers
sensors
gases
acetylene