Circularly Polarized Light Detector Based On 2D Embedded Chiral Nanostructures

Circularly polarized light is widely used in magnetic recording,quantum computation and spin optical communication because it can lead to enhanced security in fibre and free-space communication.The electric field vector of circularly polarized light moves along the spiral trajectory.According to the spiral direction,it can be divided into left and right hand circularly polarized light.Conventional photodetectors use multiple optical elements to distinguish circularly polarized light,which makes it challenging to realize ultracompact and integrated circularly polarized light detectors.Under these circumstances,this paper designs an embedded circularly polarized light detector based on chiral metamaterials:A silicon-based embedded nanophotoelectrode for circularly polarized light detection is designed.The physical model of the photoelectrode is given by analyzing the mechanism of hot electron excitation and high speed collection in the nanoelectrode.The three steps of thermal electrons from excitation to collection are described from the perspective of device physics.The numerical analysis of internal quantum efficiency at different embedding depths is given.The internal quantum efficiency of embedded nanowires can have 6×greater than comparable planar Schottky devices at the wavelength of 1550nm.Combining the advantages of chiral structure and embedded structure,a circularly polarized light detector based on embedded chiral metamaterial is proposed.The structure of the circularly polarized photodetector was further optimized by numerical analysis of the light absorption,circular dichroism,and optical response difference of the device.The device absorbs the incident circularly polarized light differentially by the chiral electrode structure,and uses the embedded electrode structure to collect the hot electrons ultrafastly,and obtains better photoelectric performance.The simulation results domenstrate that the device achieves more than 75%circular dichroism and 21mA W^-1 difference of photoresponsivity at a wavelength of 1550 nm.The silicon-based device has great application potential in the field of ultrafast optical communication due to easy to integrate,large photoelectric response rate and excellent circular dichroism.