Explicit description of polarization coupling in lidar applications

Depolarization lidar requires discrimination of received power in polarized and unpolarized components of backscattered light. This can be accomplished with only two polarization measurements. However, parallel- and cross-polarization channels in depolarization lidar cannot always be regarded as independent, because system optical components can cause coupling between these channels and transmitter and receiver polarization planes are rarely perfectly aligned. Calibration constants, while in some instances reasonable approximations, do not fully describe the physics of the receiver and potential for coupling between orthogonal polarization modes. We present an analysis of a general receiver design and introduce an algorithm for decoupling the received data, which only requires the parallel- and cross-polarization data typically recorded in depolarization lidar measurements.