Phase-shifting interferometry-based Fourier transform channeled spectropolarimeter

Channeled spectropolarimetry is a snapshot technique for measuring the spectral dependence of the state of polarization of light. However, it suffers from two major limitations, namely, its high sensitivity to environmental perturbations and its susceptibility to channel crosstalk. These limitations reduce the polarimetric reconstruction accuracy of the spectropolarimeter. A new calibration technique for channeled spectropolarimetry is presented that utilizes the concept of phase-shifting interferometry to accurately acquire and demodulate the retardation phase factors, thereby improving the accuracy of the Stokes data reconstruction as well as enabling more robust performance. The new technique also enables the acquisition of high-resolution intensity spectrum by adopting a dual-scan measurement technique for reducing crosstalk. Experimental results show that calibrations using phase-shifting interferometry yield higher data reconstruction accuracy as compared to the self-calibration technique.