Hybrid polarization grating for mode detection of vector beams

A hybrid polarization grating that can spatially separate orthogonal states of a vector beam with the same polarization topological charge is presented. The hybrid polarization grating is assembled using a fork-shaped polarization grating and a quarter-wave polarization grating and acts as a common pass interferometer for right- and left-circular polarization components of incident vector beams. The hybrid polarization grating can separate two vector beam states that have a 90 degrees relative polarization azimuth angle difference. The number of detectable vector beams can be increased by replacing the hybrid polarization grating with a crossed-hybrid polarization grating. Device feasibility was demonstrated experimentally using hybrid polarization grating and crossed-hybrid polarization grating fabricated using the photoalignment method for photoreactive liquid crystals. This approach has the potential to demultiplex several vector beams stably and simultaneously using a compact optical system and should be applicable to vector beam division multiplexing and other applications requiring vector beam detection. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

A hybrid polarization grating capable of spatially separating vector beams with the same polarization topological charge is presented, which can increase the number of detectable vector beams. This device shows promise for stable demultiplexing of multiple vector beams using a compact optical system.