Abstract
The heterodyne efficiency of the coherent Doppler lidar (CDL) is a key parameter in the determination of its operational performance. The spatial coherence of the backscattering signal is affected by the fluctuations in the atmospheric refractive index (caused by atmospheric fluctuations) during the propagation of the laser in the atmosphere. We present the analytical equation that includes atmospheric fluctuations and measure the heterodyne efficiency for a 2.0-µm CDL. The experimental results are in the good agreement with the simulated predictions and certify the validity of the analytical equation including the atmospheric fluctuations.