Polarization Raman microscope based on channeled spectropolarimetry

A channeled polarization Raman microscope (CPRM) based on spectrally-modulated polarimetry is introduced. The CPRM modulates the polarization information into a spectrum by an achromatic quarter-wave plate, a high order retarder, and a linear polarizer. The linear Stokes parameters of Raman scattered light can be decoded from this spectrum by the Fourier transformation method (FTM). When compared with the traditional polarization Raman microscope, the proposed system removes the need of rotating the analyzer multiple times for the analysis of the polarization state, thus accelerating the data acquisition process. The feasibility and correctness of CPRM are validated by experiments, and the results of the instrument are shown in point and mapping spectroscopy modes. The results on polypropylene fiber and tooth samples confirm CPRM’s abilities to characterize molecular orientation and enhance image contrast.