Saturation Effects in Ca/Ca+ Resonance Lidar Measurements

Kurzfassung

Saturation effects, whereby a nonlinear response from the scattering layer due to high energy concentrations, have been known since at least the 1970’s to play a role in resonance lidar measurements. The trend towards larger laser pulse energies, narrower laser linewidths, and smaller beam divergences exacerbates these effects. Nonetheless, saturation effects have never been properly addressed in the context of Ca and Ca+ lidar systems. Here, we present a tool for estimating the degree of saturation for modern Ca/Ca+ lidar systems; we show that modern systems may induce significant saturation, leading to biases on inferred densities and temperatures; and we demonstrate how saturation effects can be reduced.