Continuous wave, distributed feedback diode laser based sensor for trace-gas detection of ethane
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The development of a continuous wave (CW), thermoelectrically cooled (TEC), distributed feedback (DFB) laser diode based spectroscopic trace-gas sensor for ultra-sensitive and selective ethane (C2H6) concentration measurements is reported. The sensor platform used tunable diode laser absorption spectroscopy (TDLAS) based on a 2f wavelength modulation (WM) detection technique. TDLAS was performed with a 100 m optical path length astigmatic Herriott cell. For an interference free C2H6 absorption line located at 2976.8 cm−1 a 1σ minimum detection limit of 240 pptv (part per trillion by volume) with a 1 second lock-in amplifier time constant was achieved. In addition, reliable and long-term sensor performance was obtained when operating the sensor in an absorption line locked mode.
KeywordsLaser Diode Tunable Diode Laser Absorption Spectroscopy Semiconductor Laser Diode Laser Diode Beam Interband Cascade Laser
The Rice University group acknowledges the financial support from a National Science Foundation (NSF) Engineering Research Center sub award for “Mid-infrared Technologies for Health and the Environment (MIRTHE)” from Princeton University, a NSF International Collaboration in Chemistry award: NexCILAS CHE-1124577 and grant C-0586 from The Welch Foundation. The development of the laser diode was supported by the European Commission within the project SensHy 223998 of the 7th Framework Program. The laser diode was processed by nanoplus GmbH, Germany.
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