A Linear Phase Gradient Metasurface Structure Based on Highly Reflective Membranes

Abstract

The invention relates to a linear phase gradient metasurface structure based on a high reflection film, comprising a substrate (1), a high reflection film (2) and a metasurface (3) arranged sequentially from bottom to top, the high reflection film ( 2) It is a dielectric film stack composed of high-refractive-index dielectric film layers H1 and low-refractive-index dielectric film layers L alternately arranged, and the side where the high-reflection film (2) is in contact with the metasurface (3) is a low-refractive index dielectric film layer L, the metasurface (3) adopts a high refractive index medium film layer H2, and a period of the metasurface (3) is composed of multiple unit structures with different widths. Compared with the prior art, the present invention omits the traditional thick-layer metal substrate and introduces a full-dielectric high-reflection film, which improves the reflectivity of the metasurface and reduces the loss of the metasurface. The laser wavelengths achieve anomalous reflection and deflection efficiencies of 99% and 98% by design and experiment, respectively.

Description

technical field [0001] The invention relates to the field of electromagnetic wave phase regulation, in particular to a linear phase gradient metasurface structure based on a high reflection film. Background technique [0002] As a two-dimensional form of metamaterials, metasurfaces have made important progress in anomalous deflection, polarized optics, metalens, vortex optics, and holographic imaging. [0003] Abnormal deflection is the basic operation of regulating light, and its efficiency directly affects the performance of metasurface devices. At the same time, abnormally deflected metasurfaces have great application prospects in spectrometers, autonomous driving and other fields, so it is very important to improve their efficiency. Transmissive anomalous deflection High deflection efficiency has been achieved by using all-dielectric metasurfaces to reduce reflection and absorption. The reflective anomalous deflection mainly adopts the method of metal substrate to impr...

AI Technical Summary

Problems solved by technology

The reflective anomalous deflection mainly adopts the method of metal substrate to improve the reflectivity, and then realizes phase gradient to achieve high-efficiency anomalous reflection by designing the outermost metal or dielectric metasurface. Efficiency is lower than 90%

Due to the absorption characteristics of metals in the infrared and visible light bands, it is difficult to improve the efficiency of such metasurfaces, and it is not conducive to integration

At the same time, due to the high transmission characteristics of the medium, there is currently no good way to use the all-dielectric metasurface to achieve anomalous reflection and deflection efficiency beyond that of the metal metasurface in the visible to infrared range.

Images