System and method for simultaneous high-sensitivity measurement of methane and ethane via laser absorption spectroscopy in open air constructions

A system for measuring a target gas via laser absorption spectroscopy in an open air configuration includes: a mid-infrared distributed feedback inter-band cascade laser (mid-infrared DFB-ICL) having a wavelength selected to correspond to a spectral absorption line of the target gas; and a first electronic circuit for controlling laser temperature, current, and modulation frequency. The mid-infrared DFB-ICL is mounted to the heat sink. The system comprises an optical component which projects a light beam of the mid-infrared DFB-ICL to a far-end backscattering directional reflection target; and a light receiver assembly that receives a portion of the laser light backscattered from the directed reflection target and focuses the collected light to the uncooled photodetector, the spectral bandwidth and optical configuration of the uncooled photodetector being selected to optimize the signal-to-noise ratio response of the received laser light. The light receiver assembly includes a primary mirror for receiving las