Ben van Well et al 2005 J. Opt. A: Pure Appl. Opt. 7 S420 doi:10.1088/1464-4258/7/6/025
Ben van Well1,5, Stuart Murray2, Jane Hodgkinson3, Russ Pride3, Rainer Strzoda4, Graham Gibson1 and Miles Padgett1
Show affiliationsWe have developed an open-path hand-held gas detector incorporating a distributed feedback InGaAs laser diode at 1.65 µm. Incorporated into a hand-held transceiver unit, the emitted laser beam is backscattered from nearby surfaces, collected and focused onto an amplified InGaAs detector using a 150 mm diameter plastic Fresnel lens. At ranges of 4–5 m, a typical backscattered signal is tens of nanowatts of laser light. Applying second derivative wavelength modulation spectroscopy gives a sensitivity to methane of better than 10 parts per million over a one metre path length. A number of demonstration units have been fabricated and successfully evaluated by end users.
42.55.Px Semiconductor lasers; laser diodes
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques
42.79.Bh Lenses, prisms and mirrors
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
82.80.-d Chemical analysis and related physical methods of analysis
Instrumentation and measurement
Issue 6 (June 2005)
Received 18 October 2004, accepted for publication 1 February 2005
Published 13 May 2005
Ben van Well et al 2005 J. Opt. A: Pure Appl. Opt. 7 S420
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