Full-Stokes polarization short-wave infrared photodetector based on the doubly regulated dielectric metasurfaces

Abstract

Fully polarization photodetectors based on miniature metasurface filters have attracted much attention because they can directly detect polarized signals that cannot be perceived by the human eye. Although some structures have been proposed to break the spatial symmetry to obtain chirality, the circular polarization extinction ratio of the polarization detector is still not high enough, which severely limits the application of the device in complex polarization scenarios. Here, we gradually enhance the structural chirality of the metasurface based on the dual manipulation of displacement and rotation, and the circular dichroism and circular polarization extinction ratio of the circularly polarized photodetector reach 86 % and 22 dB, respectively, at an operating wavelength of 1530 nm. Four linearly polarized pixels and two chiral pixels can accurately restore the Stokes parameter of the polarized light through the 6-in-1 scheme, and their errors of the degree of linear polarization and the degree of circular polarization are −25 dB and −20 dB, respectively. This fully polarized photodetector is expected to advance the detection dimension from the traditional intensity detection to the new polarization detection field.