Polarization-independent broadband absorber based on conical metal-dielectric multilayer grating structure

Abstract

The invention relates to a polarization-independent broadband absorber which is used for infrared band and based on a conical metal-dielectric multilayer grating structure. The polarization-independent broadband absorber comprises a metal-dielectric multilayer grating, a metal film reflecting layer and a dielectric substrate which are arranged from top to bottom, wherein the period d of the metal-dielectric multilayer grating is 1640-1645 nm, the metal-dielectric multilayer grating is formed by overlaying N pairs of metal gratings and dielectric gratings, and the duty cycle is gradually increased from top to bottom. When TE light and TM polarized light are vertically incident, the incident light in one relatively broad wave band range of the infrared band can be absorbed, bandwidth with polarization-independent absorption rate exceeding 90% is greater than 2 microns, and high polarization-independent absorption can be maintained in a great incident angle range, so that the polarization-independent broadband absorber provided by the invention has great angle independence and can be widely applied to the fields of thermo-photovoltaic devices, infrared stealth and the like. The polarization-independent broadband absorber provided by the invention is processed by combining a microelectronic deep etching technology, has easy accessibility of materials, low manufacturing cost and important practical prospect, and can realize mass production.

Description

technical field [0001] This patent relates to a broadband spectral absorber, especially a polarization-independent broadband absorber based on a tapered metal-dielectric multilayer grating structure for infrared bands. Background technique [0002] Generally speaking, spectral absorbers based on subwavelength structures are divided into two types: one has ideal absorption in a narrow bandwidth, and is mainly used to design high-sensitivity detectors, thermal imaging devices, and narrow-band absorption / thermal radiation is often referred to as a selective absorber. The other has high absorption in a wide band range, called broadband absorber, which is mainly used in solar cells, thermal photovoltaic devices and stealth and other fields. At present, research on broadband absorption based on subwavelength structures has become a hot topic. [0003] However, the current absorbers have the defects of narrow absorption bandwidth and sensitivity to polarization. In order to expa...

AI Technical Summary

Problems solved by technology

Nevertheless, these polarization-independent broadband absorbers based on 2D anisotropic metamaterials are difficult to fabricate, which also limits their potential applications.

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