Continuous-wave differential absorption lidar

This work proves the feasibility of a novel concept of differential absorption lidar based on the Scheimpflug principle. The range-resolved atmospheric backscattering signal of a laser beam is retrieved by employing a tilted linear sensor with a Newtonian telescope, satisfying the Scheimpflug condition. Infinite focus depth is achieved despite employing a large optical aperture. The concept is demonstrated by measuring the range-resolved atmospheric oxygen concentration with a tunable continuous-wave narrow-band laser diode emitting around 761 nm over a path of one kilometer during night time. Laser power requirements for daytime operation are also investigated and validated with single-band atmospheric aerosol measurements by employing a broad-band 3.2-W laser diode. The results presented in this work show the potential of employing the continuous-wave differential absorption lidar (CW-DIAL) technique for remote profiling of atmospheric gases in daytime if high-power [GRAPHICS] narrow-band continuous-wave light sources were to be employed.