Abstract

We present a Herriott-type multipass laser absorption spectrometer enhanced by optical heterodyne detection. The proposal is demonstrated by measuring the spectra of water vapor molecule in the region from 12247.6873 to 12249.6954 cm-1. Compared with direct absorption spectroscopy, the signal-to-noise ratio is improved nearly one magnitude of factor by combining with the optical heterodyne spectroscopy and extra weak absorption lines are observed. The minimum detectable absorption is estimated at 4.36×10-8 cm-1and the measured line shape dominated by Doppler broadening can be precisely recovered by direct transformation of experimental optical heterodyne spectral profile.

© 2015 Chinese Optics Letters

Narrow optical interference fringes for certain setup conditions in multipass absorption cells of the Herriott type

J. Barry McManus and Paul L. Kebabian
Appl. Opt. 29(7) 898-900 (1990)

Multilaser Herriott cell for planetary tunable laser spectrometers

Christopher G. Tarsitano and Christopher R. Webster
Appl. Opt. 46(28) 6923-6935 (2007)

Signal-to-noise ratio analysis in laser absorption spectrometers using optical multipass cells

Peter Werle and Franz Slemr
Appl. Opt. 30(4) 430-434 (1991)

Multipass optical absorption spectroscopy: a fast-scanning laser spectrometer for the in situ determination of atmospheric trace-gas components, in particular OH

W. Armerding, M. Spiekermann, J. Walter, and F. J. Comes
Appl. Opt. 35(21) 4206-4219 (1996)

Laser heterodyne spectrometer for helioseismology

David A. Glenar, Drake Deming, Fred Espenak, Theodor Kostiuk, and Michael J. Mumma
Appl. Opt. 25(1) 58-62 (1986)