Diode laser spectroscopy using a calibration free phasor decomposition approach with RAM nulling

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

Research output: Contribution to conferencePaper

Abstract

A limiting factor of tunable diode laser spectroscopy (TDLS) analysis is the large unwanted residual amplitude modulation (RAM) background present on the recovered 1st harmonic signal. A novel approach to remove the background RAM will be presented. This new technique will be used alongside the phasor decomposition method (PDM) [1], a calibration free technique for recovery of the absolute gas absorption line-shape. The RAM nulling method developed, successfully removes the background by optical cancellation. This is
achieved by placing a fibre delay line, which introduces a π phase change in the modulation signal, in parallel with the gas cell line. When these lines are coupled together the background signals are at anti-phase and hence cancel each other. The main benefit being that measurement sensitivity can be increased. Results illustrating RAM nulling whilst using the PDM technique for absorption line-shape recovery will be presented. Figure 1 shows a recorded PDM measurement illustrating the difference with and without RAM Nulling.

Conference

Conference7th International Conference on Tunable Diode Laser Spectroscopy
CityZermatt, Switzerland
Period13/07/0917/07/09

Fingerprint

laser spectroscopy
diodes
decomposition
line shape
recovery
delay lines
gases
cultured cells
cancellation
harmonics
modulation
fibers

Keywords

  • tunable diode laser spectroscopy
  • residual amplitude modulation
  • phasor decomposition method
  • absolute gas absorption
  • optical cancellation

Cite this

Ruxton, K. C., Chakraborty, A., McGettrick, A. J., Duffin, K., Johnstone, W., & Stewart, G. (2009). Diode laser spectroscopy using a calibration free phasor decomposition approach with RAM nulling. 80. Paper presented at 7th International Conference on Tunable Diode Laser Spectroscopy, Zermatt, Switzerland, .
Ruxton, K.C. ; Chakraborty, A. ; McGettrick, A.J. ; Duffin, K. ; Johnstone, W. ; Stewart, G. / Diode laser spectroscopy using a calibration free phasor decomposition approach with RAM nulling. Paper presented at 7th International Conference on Tunable Diode Laser Spectroscopy, Zermatt, Switzerland, .1 p.
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title = "Diode laser spectroscopy using a calibration free phasor decomposition approach with RAM nulling",
abstract = "A limiting factor of tunable diode laser spectroscopy (TDLS) analysis is the large unwanted residual amplitude modulation (RAM) background present on the recovered 1st harmonic signal. A novel approach to remove the background RAM will be presented. This new technique will be used alongside the phasor decomposition method (PDM) [1], a calibration free technique for recovery of the absolute gas absorption line-shape. The RAM nulling method developed, successfully removes the background by optical cancellation. This is achieved by placing a fibre delay line, which introduces a π phase change in the modulation signal, in parallel with the gas cell line. When these lines are coupled together the background signals are at anti-phase and hence cancel each other. The main benefit being that measurement sensitivity can be increased. Results illustrating RAM nulling whilst using the PDM technique for absorption line-shape recovery will be presented. Figure 1 shows a recorded PDM measurement illustrating the difference with and without RAM Nulling.",
keywords = "tunable diode laser spectroscopy, residual amplitude modulation , phasor decomposition method , absolute gas absorption, optical cancellation",
author = "K.C. Ruxton and A. Chakraborty and A.J. McGettrick and K. Duffin and W. Johnstone and G. Stewart",
year = "2009",
month = "7",
language = "English",
pages = "80",
note = "7th International Conference on Tunable Diode Laser Spectroscopy ; Conference date: 13-07-2009 Through 17-07-2009",

}

Ruxton, KC, Chakraborty, A, McGettrick, AJ, Duffin, K, Johnstone, W & Stewart, G 2009, 'Diode laser spectroscopy using a calibration free phasor decomposition approach with RAM nulling' Paper presented at 7th International Conference on Tunable Diode Laser Spectroscopy, Zermatt, Switzerland, 13/07/09 - 17/07/09, pp. 80.

Diode laser spectroscopy using a calibration free phasor decomposition approach with RAM nulling. / Ruxton, K.C.; Chakraborty, A.; McGettrick, A.J.; Duffin, K.; Johnstone, W.; Stewart, G.

2009. 80 Paper presented at 7th International Conference on Tunable Diode Laser Spectroscopy, Zermatt, Switzerland, .

Research output: Contribution to conferencePaper

TY - CONF

T1 - Diode laser spectroscopy using a calibration free phasor decomposition approach with RAM nulling

AU - Ruxton, K.C.

AU - Chakraborty, A.

AU - McGettrick, A.J.

AU - Duffin, K.

AU - Johnstone, W.

AU - Stewart, G.

PY - 2009/7

Y1 - 2009/7

N2 - A limiting factor of tunable diode laser spectroscopy (TDLS) analysis is the large unwanted residual amplitude modulation (RAM) background present on the recovered 1st harmonic signal. A novel approach to remove the background RAM will be presented. This new technique will be used alongside the phasor decomposition method (PDM) [1], a calibration free technique for recovery of the absolute gas absorption line-shape. The RAM nulling method developed, successfully removes the background by optical cancellation. This is achieved by placing a fibre delay line, which introduces a π phase change in the modulation signal, in parallel with the gas cell line. When these lines are coupled together the background signals are at anti-phase and hence cancel each other. The main benefit being that measurement sensitivity can be increased. Results illustrating RAM nulling whilst using the PDM technique for absorption line-shape recovery will be presented. Figure 1 shows a recorded PDM measurement illustrating the difference with and without RAM Nulling.

AB - A limiting factor of tunable diode laser spectroscopy (TDLS) analysis is the large unwanted residual amplitude modulation (RAM) background present on the recovered 1st harmonic signal. A novel approach to remove the background RAM will be presented. This new technique will be used alongside the phasor decomposition method (PDM) [1], a calibration free technique for recovery of the absolute gas absorption line-shape. The RAM nulling method developed, successfully removes the background by optical cancellation. This is achieved by placing a fibre delay line, which introduces a π phase change in the modulation signal, in parallel with the gas cell line. When these lines are coupled together the background signals are at anti-phase and hence cancel each other. The main benefit being that measurement sensitivity can be increased. Results illustrating RAM nulling whilst using the PDM technique for absorption line-shape recovery will be presented. Figure 1 shows a recorded PDM measurement illustrating the difference with and without RAM Nulling.

KW - tunable diode laser spectroscopy

KW - residual amplitude modulation

KW - phasor decomposition method

KW - absolute gas absorption

KW - optical cancellation

UR - http://tdls.conncoll.edu/2009/ABSTRACTBOOK2009.pdf

M3 - Paper

SP - 80

ER -

Ruxton KC, Chakraborty A, McGettrick AJ, Duffin K, Johnstone W, Stewart G. Diode laser spectroscopy using a calibration free phasor decomposition approach with RAM nulling. 2009. Paper presented at 7th International Conference on Tunable Diode Laser Spectroscopy, Zermatt, Switzerland, .