Comb segmentation spectroscopy for rapid detection of molecular absorption lines

Abstract

We perform fast comb spectroscopy by dividing the probe comb into several sub-comb segments so as to produce multi-heterodyne beats focused around targeted molecular absorption lines. This concentrated scheme of comb spectroscopy is able to achieve a 30 dB signal-to-noise ratio with just a single shot measurement of 10 mu s acquisition time. Such high signal sensitivity is Verified by measuring separate absorption lines of (HCN)-C-13-N-14 and (CO2)-C-12 gases simultaneously. In addition, atmospheric (CO2)-C-12 concentration over a 1.3 km open-air path is traced with a signal repeatability of 15 ppm at a 5 kHz update rate. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement