Broadband spatial polarization processing of light via a photopatterned dichroic medium.

Vector beams, featured by a specific space-variant distribution of polarization, have attracted intensive attention. Arbitrary and broadband spatial polarization processing is a key pursuit for vector beam generation, modulation, and detection. Here, we introduce black dye into liquid crystals to form a dichroic medium and imprint high-resolution patterns into the medium via photopatterning. Continuous cylindrical and binary vector beams are freely generated. Switching between a vector beam generator and a high-transmittance homeotropic state can be realized due to the electro-optical tunability of liquid crystals. On the basis of a radial vector beam generator array, the polarization distribution is characterized by calculating the darkest line of each generator. This strategy provides a platform for arbitrary spatial polarization processing and may bring more possibilities for polarization imaging, structured light generation, and materials characterization. [ABSTRACT FROM AUTHOR]