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

Keith Ruxton; Arup Lal Chakraborty; Andrew J. McGettrick; Kevin Duffin; Walter Johnstone; George Stewart

doi:10.1117/12.833000

5 October 2009 Recent advance in tunable diode laser spectroscopy with background RAM nulling for industrial applications

Keith Ruxton, Arup Lal Chakraborty, Andrew J. McGettrick, Kevin Duffin, Walter Johnstone, George Stewart

Author Affiliations +

Proceedings Volume 7503, 20th International Conference on Optical Fibre Sensors; 750313 (2009) https://doi.org/10.1117/12.833000
Event: 20th International Conference on Optical Fibre Sensors, 2009, Edinburgh, United Kingdom

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 1^st 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 1^st derivative of the line-shape from the 1^st 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.

Citation Download Citation

Keith Ruxton, Arup Lal Chakraborty, Andrew J. McGettrick, Kevin Duffin, Walter Johnstone, and George Stewart "Recent advance in tunable diode laser spectroscopy with background RAM nulling for industrial applications", Proc. SPIE 7503, 20th International Conference on Optical Fibre Sensors, 750313 (5 October 2009); https://doi.org/10.1117/12.833000

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available