Abstract

Remote measurement of methane by absorption of laser light has been previously accomplished by, for example, integrated path detection using DF¹ or Er:YAG² systems and DIAL using an optical parametric oscillator.³ Geometrically range-resolved DIAL-Mie backscatter remote detection of methane in a simulated coal mine environment has also been demonstrated with an Er:YAG device.⁴ Theoretical and experimental work toward use of room temperature III–V compound semiconductor lasers as sources in a portable methanometer for use in coal mines is described in this paper. Accurate measurement of methane concentrations requires use of a wavelength free from absorption by other naturally occurring atmospheric and coal gas species while overlapping a methane absorption band.

© 1983 Optical Society of America