Compact and efficient 1064 nm up-conversion atmospheric lidar.

A model was developed to simulate lidar signals and quantify the relative errors of retrieved aerosol backscattering. The results show that a 1064 nm atmospheric aerosol lidar has a small relative error, which can be attributed to the presence of a sufficient molecular signal to facilitate calibration. However, the quantum efficiency of 1064 nm photons using silicon avalanche photodiode detectors is about 2%. To improve the quantum efficiency at 1064 nm band, this study used up-conversion techniques to convert 1064-nm photons to 631-nm photons, optimizing the power of the pump laser and the operating temperature of the waveguide to enable detection at higher efficiencies, up to 18.8%. The up-conversion atmospheric lidar is designed for optimal integration and robustness with a fiber-coupled optical path and a 50 mm effective aperture telescope. This greatly improves the performance of the 1064 nm atmospheric aerosol lidar, which enables aerosol detection up to 25 km (equivalent to 8.6 km altitude) even at a single laser pulse energy of 110 µJ. Compared to silicon avalanche photodiode detectors, up-conversion single photon detectors exhibit superior performance in detecting lidar echo signals, even in the presence of strong background noise during daytime.