Preparation method of ZnS infrared window antireflective microstructure surface

Abstract

The invention discloses a preparation method of a ZnS infrared window antireflective microstructure surface. The preparation method sequentially comprises the steps of ZnS substrate cleaning, Al filmpreparation/polymer film coating, preparation of a micropore structure array in an Al film or a polymer film, plasma etching and film removal. According to the method, an Al film or a polymer film (PMMA (Polymethyl Methacrylate) or photoresist) is prepared on a ZnS surface firstly, a micropore array is prepared in the film by an ultra-fast pulse laser direct writing technology secondly, and patterns in the film are etched onto the ZnS substrate by a plasma etching technology lastly, so that an antireflective microstructure surface with an antireflective effect can be obtained after film removal. The method has high process stability and high controllability, and micropore arrays which are uniform in geometric sizes and are orderly arranged can be prepared on a large-area substrate.

Description

technical field [0001] The invention relates to the technical field of infrared optical windows, in particular to a method for preparing a ZnS infrared window anti-reflection microstructure surface. Background technique [0002] Zinc sulfide (ZnS) is the most promising infrared optical window material for the 8-12 μm long-wave infrared band, but its refractive index is relatively high, 2.2, the surface reflection is too large, and the final transmittance is only about 74%, which cannot meet the requirements of the application. need. Therefore, surface anti-reflection treatment must be performed on ZnS. Compared with the traditional anti-reflection film, the anti-reflection microstructure surface is directly processed on the surface of the substrate material, and a good optical matching effect can be achieved by adjusting the geometric size of the structure, thereby playing an anti-reflection role. Therefore, the anti-reflection microstructured surface can overcome the prob...

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Problems solved by technology

[0004] In the above-mentioned prior art, the laser interference lithography technology used in document ① has strict requirements on the preparation conditions, and the formed laser interference pattern is very sensitive to noise and vibration, so it is unstable, so it is relatively difficult; the method used in document ② Due to the limitation of the diffraction limit, the traditional ultraviolet lithography technology found is difficult to prepare pattern arrays with uniform size distribution and shape in a large area; the self-assembly technology used in literature ③ cannot form periodic arrays with uniform structure sizes; The laser direct writing technology used in literature ④ cannot well control the depth of the prepared microholes, so the anti-reflection effect is limited

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