Two-dimensional measurement technique for birefringence vector distributions: data processing and experimental verification

A two-dimensional measurement method for a birefringence vector distribution differs from a point-measurement method not only in the two-dimensional system nonuniformity but also in the system reliability. The previously proposed intrinsic vector allowed for the elimination of the influence of the system nonuniformity, whereas the two-dimensional system reliability is ensured by both an online diagnosis technique and an image lock-in processing. It is revealed that the measured intrinsic vector is relevant not only with the birefringence vector distribution in a sample but also with the natural birefringence vector distributions that exist in the optic components. The complete solution from the measured intrinsic vector results in a bidirectional vector for the desired birefringence vector distribution. The correctness of the two-dimensional measurement principle is examined by means of a comparison of the measured data with that calculated from a finite-element analysis based on the photoelastic effect.