Range-resolved laser backscattering measurements in laboratory clouds

A selective chopping method has been used to make range-resolved measurements of the backscattering of CW laser radiation at 514 nm from laboratory water droplet clouds. With incident linearly polarized radiation, the backscattered components polarized parallel and perpendicular to the incident polarization have been measured as a function of cloud penetration depth. The increase in the multiple-scattering contribution with increasing cloud density and penetration depth is measured, and compares well with the increase observed in the atmosphere with time-of-flight lidar systems. The results demonstrate the capability of the technique for making range-resolved laser scattering measurements in the laboratory equivalent to time-of-flight temporal resolutions of less than 100 psec.