Photocurrent detection of radially polarized optical vortex with hot electrons in Au/GaN

We report a GaN based metal–semiconductor–metal (MSM) infrared photodetector enabled with azimuthally distributed sub-wavelength gratings fabricated on one of the working electrodes. Under illumination, hot electron transfer is introduced by plasmonic resonance in waveband formed at interface Au/GaN. Without help using any external optical polarizers, device able to detect radial polarization vortices form photocurrents prescribed response spectrum. The detector exhibits 10%–90% rise and fall time 0.9 ms under modulated light, much faster than that conventional ultraviolet MSM photodetectors band edge absorption. This work provides viable way measure spatially variant beams compact from wide bandgap semiconductors.