Continuous wave, distributed feedback diode laser based sensor for trace-gas detection of ethane
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- Krzempek, K., Lewicki, R., Nähle, L. et al. Appl. Phys. B (2012) 106: 251. doi:10.1007/s00340-011-4857-9
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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.