Multilayer symmetrical two-dimensional transmission grating with adjustable central wavelength of 10-14 microns and preparation method thereof

Abstract

The invention discloses a multilayer symmetrical two-dimensional transmission grating with an adjustable central wavelength of 10-14 microns and a preparation method thereof, so as to solve the problem of processing errors of an FP cavity optical filter in a long-wave infrared band due to a complex film system. The grating comprises a grating layer, a substrate layer and symmetrical high-reflection layers, wherein the total number of the symmetrical high-reflection layers is eight from top to bottom, and the substrate layer is the lowest layer of the symmetrical high-reflection layers; the symmetric high-reflection layers are alternately arranged through a metal material and a dielectric material; the metal material is a high-refractive-index material germanium, and the dielectric materialis a low-refractive-index material yttrium fluoride; the grating layer is made of a high-refractive-index material germanium, in the symmetric high-reflection layer, the refractive-index material germanium and the low-refractive-index material yttrium fluoride are alternately arranged, and the thickness of the high-reflection layer is a quarter wavelength; the substrate layer is made of germanium; and the grating layer is located between the fourth layer and the fifth layer which are arranged from top to bottom in the high-reflection layer.

Description

technical field [0001] The invention belongs to the technical field of micro-nano device design, and relates to a multi-layer symmetrical two-dimensional transmission grating structure with an adjustable central wavelength of 10-14 microns. Background technique [0002] Filter-based hyperspectral imaging technology can acquire high-resolution images quickly and in real time, so it has been widely used in real-time detection and classification. At present, the main technology of spectral imaging is pixel chip coating, and it is mostly used in visible light, near-infrared and mid-infrared bands. However, most of the long-wave infrared bands pass through the central wavelength of a specific band by changing the cavity depth of the FP cavity or filling the medium. Usually, the film system is complex and the number of layers is large, and the increase in the thickness of the film layer during the preparation process will lead to stress deformation, which brings difficulties to t...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a multi-layer symmetrical two-dimensional transmission grating whose duty cycle can be freely adjusted between 0-1 at 10-14 micron, which solves the problems caused by the film system of the FP cavity filter in the long-wave infrared band. Complexity brings errors to processing

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