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

Keith C. Ruxton, Arup Lal Chakraborty, A.J. McGettrick, K. Duffin, W. Johnstone, G. Stewart

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

A limiting factor of tuneable diode laser spectroscopy (TDLS) with wavelength modulation spectroscopy (WMS) is the presence of background residual amplitude modulation (RAM) on the recovered 1st harmonic signal. The presence of this background term is due to direct modulation of the source laser power. This work presents a novel method to optically remove the unwanted background, with the major benefit being that measurement sensitivity can be increased. The recently developed phasor decomposition method1 (PDM), is a near IR (NIR) TDLS analysis technique that is used with the addition of the new RAM nulling method to recover gas absorption line-shapes. The PDM is a calibration free approach, which recovers the gas absorption line-shape and the isolated 1st derivative of the line-shape from the 1st harmonic signal. The work presented illustrates and validates the new RAM nulling procedure with measurements examining the 1650.96nm absorption line of methane (CH4) with comparisons to theory.
LanguageEnglish
JournalProceedings of SPIE: The International Society for Optical Engineering
Volume7503
Issue number750313
DOIs
Publication statusPublished - Oct 2009

Fingerprint

Nulling
Laser Spectroscopy
Tunable Laser
Amplitude Modulation
Laser spectroscopy
Amplitude modulation
Diode Laser
Industrial Application
laser spectroscopy
Industrial applications
line shape
Semiconductor lasers
Gas absorption
diodes
Absorption
Line
Modulation
Decomposition
harmonics
modulation

Keywords

  • fiber optics
  • tunable spectroscopy
  • diode-laser spectroscopy
  • RAM nulling

Cite this

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title = "Recent advance in tunable diode-laser spectroscopy with background RAM nulling for industrial applications",
abstract = "A limiting factor of tuneable diode laser spectroscopy (TDLS) with wavelength modulation spectroscopy (WMS) is the presence of background residual amplitude modulation (RAM) on the recovered 1st harmonic signal. The presence of this background term is due to direct modulation of the source laser power. This work presents a novel method to optically remove the unwanted background, with the major benefit being that measurement sensitivity can be increased. The recently developed phasor decomposition method1 (PDM), is a near IR (NIR) TDLS analysis technique that is used with the addition of the new RAM nulling method to recover gas absorption line-shapes. The PDM is a calibration free approach, which recovers the gas absorption line-shape and the isolated 1st derivative of the line-shape from the 1st harmonic signal. The work presented illustrates and validates the new RAM nulling procedure with measurements examining the 1650.96nm absorption line of methane (CH4) with comparisons to theory.",
keywords = "fiber optics, tunable spectroscopy, diode-laser spectroscopy, RAM nulling",
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year = "2009",
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journal = "Proceedings of SPIE",
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Recent advance in tunable diode-laser spectroscopy with background RAM nulling for industrial applications. / Ruxton, Keith C.; Chakraborty, Arup Lal; McGettrick, A.J.; Duffin, K.; Johnstone, W.; Stewart, G.

In: Proceedings of SPIE: The International Society for Optical Engineering, Vol. 7503, No. 750313, 10.2009.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Recent advance in tunable diode-laser spectroscopy with background RAM nulling for industrial applications

AU - Ruxton, Keith C.

AU - Chakraborty, Arup Lal

AU - McGettrick, A.J.

AU - Duffin, K.

AU - Johnstone, W.

AU - Stewart, G.

PY - 2009/10

Y1 - 2009/10

N2 - A limiting factor of tuneable diode laser spectroscopy (TDLS) with wavelength modulation spectroscopy (WMS) is the presence of background residual amplitude modulation (RAM) on the recovered 1st harmonic signal. The presence of this background term is due to direct modulation of the source laser power. This work presents a novel method to optically remove the unwanted background, with the major benefit being that measurement sensitivity can be increased. The recently developed phasor decomposition method1 (PDM), is a near IR (NIR) TDLS analysis technique that is used with the addition of the new RAM nulling method to recover gas absorption line-shapes. The PDM is a calibration free approach, which recovers the gas absorption line-shape and the isolated 1st derivative of the line-shape from the 1st harmonic signal. The work presented illustrates and validates the new RAM nulling procedure with measurements examining the 1650.96nm absorption line of methane (CH4) with comparisons to theory.

AB - A limiting factor of tuneable diode laser spectroscopy (TDLS) with wavelength modulation spectroscopy (WMS) is the presence of background residual amplitude modulation (RAM) on the recovered 1st harmonic signal. The presence of this background term is due to direct modulation of the source laser power. This work presents a novel method to optically remove the unwanted background, with the major benefit being that measurement sensitivity can be increased. The recently developed phasor decomposition method1 (PDM), is a near IR (NIR) TDLS analysis technique that is used with the addition of the new RAM nulling method to recover gas absorption line-shapes. The PDM is a calibration free approach, which recovers the gas absorption line-shape and the isolated 1st derivative of the line-shape from the 1st harmonic signal. The work presented illustrates and validates the new RAM nulling procedure with measurements examining the 1650.96nm absorption line of methane (CH4) with comparisons to theory.

KW - fiber optics

KW - tunable spectroscopy

KW - diode-laser spectroscopy

KW - RAM nulling

U2 - 10.1117/12.833000

DO - 10.1117/12.833000

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VL - 7503

JO - Proceedings of SPIE

T2 - Proceedings of SPIE

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SN - 0277-786X

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ER -