Expected performances for a 2-μm differential absorption lidar using new HgCdTe avalanche photodiodes

Differential absorption lidar (DIAL) is an active remote sensing technique, which has been developed to monitor trace constituents such as greenhouse gases over distances that range from hundreds of meters to tens of kilometers in the atmosphere. A DIAL lidar dedicated to CO2 probing in the atmospheric boundary layer has recently been developed at Laboratoire de Météorologie Dynamique (IPSL, France). This so-called COWI1 lidar relies on a 2μm Ho:YLF solid state laser and coherent detection. In case direct detection is used, performance on measurement strongly depends on detector performance. That is why recent advances in the field of HgCdTe avalanche photodiodes (APD) which achieve remarkable low levels of noise along with high gains in the considered spectral surrounding open the way to outstanding precision in atmospheric probing around 2μm. The aim of this study is to estimate the performance of DIAL lidar using such APDs in the framework of atmospheric CO2 probing.