Plasmon Spectral Absorption Device Based on Periodic Chirped Structure

Abstract

The invention discloses a surface-plasmon-polariton spectral absorption device based on a periodic chirp structure. The surface-plasmon-polariton spectral absorption device comprises a substrate, a first metal layer and a plurality of gratings, wherein the first metal layer is positioned on the substrate; the plurality of gratings are positioned on the first metal layer; each grating comprises an insulator body positioned on the first metal layer and a second metal layer positioned on the insulator body; and the gratings are in linear chrip at least along the X direction or Z direction or along the two directions simultaneously. The surface-plasmon-polariton spectral absorption device disclosed by the invention has the advantages that since the period of the gratings adopts the linear chrip, the resonant wavelength is in linear distribution and covers larger spectral range, and the bandwidth of the whole forbidden band is realized and widened by properly adjusting a chrip coefficient of the gratings and a resonant cavity formed by an upper metal layer / insulator layer / lower metal layer, so that the possibility for realizing a low and flat reflecting forbidden belt is realized; and under the limiting condition of phase matching and sub-wavelength size, nearly-perfect absorption of the bandwidth can be realized by proper design.

Description

technical field [0001] The invention relates to the technical field of surface plasmon resonators, in particular to a surface plasmon resonator spectral absorption device based on a periodic chirped structure. Background technique [0002] Metals are generally considered high-efficiency reflectors and are sometimes used as mirrors. However, when the metal surface is etched into a micro-nano structure according to the required working wavelength, the reflected light of the metal surface can be greatly reduced. Micro-nano structures may become highly efficient absorbers in a wide range of electromagnetic waves, from visible light, infrared to microwave. This has aroused great interest and led to a large number of theoretical and experimental studies in the past few years. In 2008, Landry et al. proposed and demonstrated an almost completely absorbing metamaterial structure. It consists of two metamaterial resonators that are coupled to electric and magnetic fields, respecti...

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Problems solved by technology

However, this structure only absorbs 70% of the incident light in the 2.5 μm band at 8.5 μm. This is because of the mutual restriction between the band and the absorption rate, which causes large fluctuations in the working wavelength range.

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