Monolithic integrated InGaAs near-infrared detector for sub-wavelength micro-polarization grating

Abstract

The invention discloses a monolithic integrated InGaAs line array or stacked array detector for a sub-wavelength micro-polarization grating. The detector is a photoelectric detector and consists of an InGaAs photosensitive chip, an anti-reflection film and the sub-wavelength micro-polarization grating, wherein the anti-reflection film is made of a low-refractive index SiO2 material, and the extinction ratio of the sub-wavelength micro-polarization grating is improved; the sub-wavelength micro-polarization grating is a polarization grating line array or array consisting of polarization units in different polarization orientations; and each polarization unit is a metal polarization grating of which the grating period is shorter than that of an incident light wavelength. The sub-wavelength micro-polarization grating is integrated on a chip of a near-infrared detector, and the invention has the main advantages that: (1) the polarization grating is monolithically integrated with the detector, an optical system is simplified, and motion parts of a polarization scanning system are eliminated; (2) high-accuracy angle quantification can be achieved, and an angle error is avoided; and (3) the polarization units in the different polarization orientations are imaged simultaneously, and accurate polarization information is acquired from a moving target.

Description

technical field [0001] The invention relates to photodetector technology, which is an InGaAs linear array or area array near-infrared detector integrated with a sub-wavelength micro-polarization grating on a single chip. The polarization grating is directly prepared on the photosensitive chip of the InGaAs detector, thereby simplifying the polarization detection system and realizing High-precision angle quantification to accurately obtain the polarization information of the target. Background technique [0002] Polarization is an important information of light. Polarization detection can expand the amount of information from three dimensions (light intensity, spectrum, space) to seven dimensions (light intensity, spectrum, space, polarization degree, polarization azimuth, polarization ellipticity, rotation direction ). Since the degree of polarization of the ground object background is much smaller than that of the artificial target, the infrared polarization detection tech...

AI Technical Summary

Problems solved by technology

The disadvantage of this traditional polarization detection system is that the formed image is time-separated, which is limited when imaging a moving target, and the angle error of the polarization element is relatively large, and the remote sensing system is not compact enough

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