Development of an automated diode-laser-based multicomponent gas sensor

Abstract

OSA grants to the Author(s) (or their employers, in the case of works made for hire) the following rights:(b)The right to post and update his or her Work on any internet site (other than the Author(s') personal web home page) provided that the following conditions are met: (i) access to the server does not depend on payment for access, subscription or membership fees; and (ii) any such posting made or updated after acceptance of the Work for publication includes and prominently displays the correct bibliographic data and an OSA copyright notice (e.g. "© 2009 The Optical Society"). 17th December 2010 date 'rights url' accessed / permission obtained: (overwrite text) Development of an automated diode-laser-based multicomponent gas sensorDirk Richter, David G. Lancaster, and Frank K. TittelThe implementation and application of a portable fiber-coupled trace-gas sensor for the detection of several trace gases, including CO 2 , CH 4 , and H 2 CO, are reported. This particular sensor is based on a cw fiber-amplified near-infrared ͑distributed Bragg reflector͒ diode laser and an external cavity diode laser that are frequency converted in a periodically poled lithium niobate crystal to the mid-IR spectroscopic fingerprint region ͑3.3-4.4 m͒. A continuous absorption spectrum of CH 4 and H 2 CO from 3.37 to 3.70 m with a spectral resolution of 40 MHz ͑ϳ0.0013 cm Ϫ1͒ demonstrated the spectral performance that can be achieved by means of automated wavelength tuning and phase matching with stepper motor control. Autonomous long-term detection of ambient CO 2 and CH 4 over a 3-and 7-day period was also demonstrated.

Difference frequency generation laser based spectrometers

“…One can extend the phasematching bandwidth (∼ 10 cm −1 ) of a single grating period in a variety of ways. For continuous tuning one can design a fan-out grating period structure in which the grating period changes a small amount over the width of a crystal and also over the beam cross section (e. g. 1 cm wide crystal with a period ranging from 22.3-23.3 μm) [12]. To achieve a continuous tuning from 3.3 to 4.4 μm, the PPLN crystal was synchronously translated while tuning the pump laser wavelength.…”

A Tunable Diode-laser Absorption Spectroscopy (TDLAS) Thermometry for Combustion Diagnostics

“…Line of Sight absorption can provide both space averaged temperature and concentration information. With the development of laser capability, measurement incorporate with two or more tunable diode lasers for multi parameter resolution is possible, and the technique has been realized by several works [2][3][4][5][6] It is very important to measure temperature and water-vapor concentration for evaluating combustion efficiency in scramjet combustor. Well attention has been paid to the thermometry design based on tunable diode-laser absorption spectroscopy (TDLAS) due to its advantages of high sensitivity, quick response, as well as system simpleness.…”

Piezo-electric tunable fiber Bragg grating diode laser for chemical sensing using wavelength modulation spectroscopy

“…Thanks to the rapid advances in optical communication systems, many tunable lasers originally developed for telecommunication applications have been successfully demonstrated in chemical sensing. These include various temperature-tuned distributed feedback (DFB) lasers, external cavity tunable diode lasers [1], Multi-section distributed Bragg reflector lasers [2], and MEMS-based tunable VCSELs [3]. Although the application requirements for telecommunications share some similarity with those for sensing, many chemical sensing tasks present their own requirements for optical components.…”