Photocurrent detection of radially polarized optical vortex with hot electrons in Au/GaN
- Resource Type
- Authors
- Hou, Y; Kappers, M; Jin, C; Oliver, R
- Source
- Applied Physics Letters. 120:202101
- Subject
- Condensed Matter::Materials Science
Physics and Astronomy (miscellaneous)
Physics::Optics
4018 Nanotechnology
51 Physical Sciences
40 Engineering
- Language
- ISSN
- 1077-3118
0003-6951
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 the plasmonic resonance in the infrared waveband formed at the interface of Au/GaN. Without the help of using any external optical polarizers, the device is able to detect radial polarization vortices in the form of photocurrents with a prescribed response spectrum. The detector exhibits a 10%–90% rise and fall time of 0.9 ms under modulated light, much faster than that of conventional ultraviolet GaN MSM photodetectors based on the band edge absorption. This work provides a viable way to measure spatially variant polarization beams with a compact plasmonic photodetectors fabricated from wide bandgap semiconductors.