Tunable lidar system based on IR OPA laser source

A lidar system with the characteristic of simultaneously monitoring several atmospheric parameters such as atmospheric aerosols load, water vapour content, temperature and density, atmospheric transmissivity, and atmospheric pollutants concentration, has been realized. This system, based on two OPA lasers pumped by a Nd:YAG laser operating at maximum repetition rate of 100 Hz, is primary dedicated to tropospheric measurements. The system is continuously tunable over the spectral range 410 nm- 2500 nm, allowing DIAL measurements in a region where most of atmospheric pollutants display absorption lines. Preliminary measurements have been carried out. We report the simultaneous temporal evolution of the aerosol backscattering coefficient profiles at 355 nm and 829 nm in a rural area. A method to select optimal couples of wavelength for DIAL measurements in the near/mid IR spectral region has been developed. A sensitivity analysis has been carried out in order to find the minimum detectable concentration, that has been demonstrated of the order of few tenths up to few part per million in volume.