Detection of isolated specular reflection for calibration of cloud thermodynamic phase estimation with quantum parametric mode sorting LIDAR

Abstract: Specular reflection can be problematic for the determination of the cloud thermodynamic phase for near-nadir-pointing space LIDARs. A LIDAR system biased towards the specular contribution for backscatter, if near-concurrent to a conventional LIDAR, could calibrate the measurements required for cloud phase determination. One such system which shows promise for this is quantum parametric mode sorting (QPMS) LIDAR. Through a non-linear interaction and time-frequency mode selectivity, this system demonstrates in-band noise-rejection beyond what linear noise filtering can provide. This level of noise-rejection means the signal strength can be minimised, therefore biasing the specular contribution to the return signal. Here we provide a theoretical model of QPMS LIDAR applied to this scenario to instruct its feasibility.