Opto-electrical and polarization performance of a mesa-structured InGaAs PIN detector integrated with subwavelength...

Polarization detection in the short-wave infrared (SWIR) region presents broad applications in target-background contrast enhancement, underwater imaging, material classification, etc. A mesa structure can prevent electrical cross talk due to its intrinsic advantages, making it potentially suited to meet the need for manufacturing smaller-sized devices to save cost and shrink volume. In this Letter, mesa-structured InGaAs PIN detectors with a spectral response ranging from 900 nm to 1700 nm and a detectivity of 6.28 × 10¹¹cm·Hz^1/2/W at 1550 nm and -0.1 V bias (room temperature) have been demonstrated. Furthermore, the devices with subwavelength gratings in four orientations show obvious polarization performance. Their extinction ratios (ERs) can reach 18:1 at 1550 nm and their transmittances are over 90%. Such a polarized device with a mesa structure could realize miniaturized SWIR polarization detection.