Abstract

Simultaneous measurements of atmospheric constituents and wind velocity in the boundary layer is of the utmost importance for environment and pollution monitoring. A CO₂ lidar is well suited for such an application for there exist a large number of coincidences between CO₂ laser lines and absorption spectra of species of interest. The molecules under study will provide the absorption features while the aerosols particles will scatter the incident light giving rise to a lidar signal. Regarding such an application, a heterodyne detection is efficient at 10 μm provided the number of speckles in a transverse plane on the receiver is small (about 4). Then, it provides with improved sensitivity with respect to direct detection at the same wavelength and Doppler frequency shift measurement.

© 1995 Optical Society of America