OPO DIAL lidar for remote measurements of atmospheric gases in the IR range

Abstract

ABSTRACT Applicability of a KTA crystal -based laser system with optical parametric oscillators (OPO) generation to lidar sounding of the atmosphere in the spectral range 3 ±4 µm is studied in this work. A technique developed for lidar sounding of traceatmospheric gases (TAG) is based on differential absorption lidar (DIAL) method and differential optical absorption spe ctroscopy (DOAS). The new technique uses broadband radiation and a CCD detector, which ensures measurement of backscattering signals with simultaneous altitude and wavelength resolution. The DIAL -DOAS technique is tested to estimate its efficiency for lida r sounding of atmospheric trace gases. The numerical simulation performed shows that a KTA -based OPO laser is a promising source of radiation for remote DIAL -DOAS sounding of the TAGs under study along surface tropospheric paths. The laser system design pr ovides a possibility of narrowing the laser line within the 0.01 ±5 cm ±1 limits. This possible improvement along with a small step of laser line tuning and the presence of absorption lines of other atmospheric gases, including atmospheric pollutants, in the spectral range under study make this laser a unique instrument for atmospheric sounding. Keywords: atmosphere, lidar sounding, DIAL, DOAS, trace gases, nonlinear crystal