Interband cascade laser-based sensor for ambient CH4
We demonstrate a mid-IR semiconductor laser-based absorption spectrometer for field measurements of ambient CH4. The field sensor uses a type II quantum cascade laser (or interband cascade laser, ICL) operating near 3.3 µm to monitor a well-isolated line in the 3 fundamental band of CH4. The ICL operates in cw mode at cryogenic temperatures. The sensor uses a multipass cell that provides an optical path of ~7 m with a 0.25-m base path. Thermoelectrically cooled InAs detectors are used along with balanced ratiometric detection to achieve a precision of 15 ppbv for a 60-s integration time. Several successful field demonstrations are carried out at sites maintained by the University of New Hampshire.
SPIE Digital Library
Digital Object Identifier (DOI)
Sonnenfroh, D. M., R.T. Wainner, M.G. Allen and R.K. Varner (2010), Interband cascade laser–based sensor for ambient CH4, SPIE Optical Engineering, 49(11), 111118.
© (2010) Society of Photo-Optical Instrumentation Engineers (SPIE)