Method to measure polarization properties of components based on bidirectional optical path.

Thanks to the ability to obtain Muller matrix of targets, Mueller matrix polarimeters are critical to many applications. However, for optical components such as submersible observation windows, which work in complex environments, the existing Mueller matrix polarimeters are infeasible. To achieve non-contact, real-time measurements for these special targets, a measurement method based on bidirectional optical path is proposed to obtain their polarization properties. The measured results are bidirectional Mueller matrixes. However, they combine forward and backward optical path effects so that they cannot directly characterize polarization properties of measured components. In this case, a decomposition method based on polar decomposition is developed to obtain a single forward Mueller matrix from a measured bidirectional Mueller matrix. To verify the proposed decomposition method and improve measurement accuracy, both simulations and the impacts of various systematic errors are analyzed and summarized carefully. Furthermore, an in-situ calibration scheme is proposed to eliminate the influences of several systemic errors. Based on the simulation results and the proposed calibration scheme, an optical path is built in laboratory. Both air and wave plates are measured so that the proposed measurement method, decomposition method and measurement accuracy are verified. Hence, the proposed measurement method is a good supplement to the existing Mueller matrix polarimeters and would play important roles in areas such as deep-sea exploration.