US 12,228,501 B2
System and method for simultaneous high-sensitivity measurement of methane and ethane via laser absorption spectroscopy in an open-air configuration
Michael B. Frish, Medford, MA (US); Shin-Juh Chen, Arlington, MA (US); Nicholas F. Aubut, Raymond, NH (US); and Richard T. Wainner, Somerville, MA (US)
Assigned to Heath Consultants Incorporated, Houston, TX (US)
Filed by HEATH CONSULTANTS INCORPORATED, Houston, TX (US)
Filed on Oct. 4, 2022, as Appl. No. 17/959,798.
Claims priority of provisional application 63/251,949, filed on Oct. 4, 2021.
Prior Publication US 2023/0107797 A1, Apr. 6, 2023
Int. Cl. G01N 21/3504 (2014.01); G01N 21/31 (2006.01); G01N 21/39 (2006.01); G01N 33/00 (2006.01)
CPC G01N 21/3504 (2013.01) [G01N 21/39 (2013.01); G01N 33/0047 (2013.01); G01N 2021/3125 (2013.01); G01N 2021/392 (2013.01); G01N 2021/399 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A system for measuring a target gas via laser absorption spectroscopy in an open-air configuration, comprising:
a mid-infrared distributed feedback interband cascade laser (mid-IR DFB-ICL) (22) having a wavelength selected to correspond with a spectral absorption line of the target gas;
first electronic circuitry to control the laser temperature, current and modulation frequency;
a heat sink (58) for the mid-IR DFB-ICL (22);
a distal backscattering directionally-reflective target (182);
an optical component (100) that projects a beam of the mid-IR DFB-ICL onto the distal backscattering directionally-reflective target (182);
an optical receiver assembly (60) that receives a fraction of the laser light that is backscattered from the directionally-reflective target (182) and focuses the collected light onto an uncooled photodetector (128).