Development of a Spectral Filtering Technique for Lidar Applications Through Generation of a 420 nm Coherent Beam

Methods to separate and filter Mie, Rayleigh and Raman scattering are required in many atmospheric lidar systems and other laser diagnostic applications. This work reports on progress towards a novel filtering technique to spectrally separate components of a backscattered signal through coherent light generation in an atomic vapor cell. Specifically, this work characterizes 420 nm (blue) light generation in a heated rubidium cell arising from the mixing of 776 nm and 780 nm pump beams. The work finds the optimal pump frequencies and cell temperature and detects a signal using pump beams as low as 0.7 μW. Progress towards using the technique to detect scattered light in a lidar application is described.