3.5-3.9[Mu]m medium wave infrared mini-type optical filter and preparation method thereof

Abstract

The present invention belongs to the technical field of surfaces, and especially relates to a 3.5-3.9[Mu]m medium wave infrared mini-type optical filter and a preparation method thereof. The optical filter comprises a silicon substrate and long-wave and medium-wave through film systems; the long-wave through film system structure is (0.35H0.7L0.35H)^9(0.5HL0.5H)^13, and the central wavelength is 2800nm; a short-wave through film system structure is (0.5LH0.5L)^13, and the central wavelength is 4650nm; H and L are a germanium film layer and a zinc sulfide film layer; the silicon substrate is heated in the vacuum, an electronic gun evaporation method assistant by an ion beam is employed to deposit long-wave and short-wave through film systems at the two sides of the substrate, and the optical filter is prepared after cooling. The optical filter has high transmittance at the 3.5-3.9[Mu]m spectrum band, and is cut off at the 0.80-3.3[Mu]m spectrum band width and 4.1-5.5[Mu]m spectrum bandwidth, and the optical filter can be used in the low temperature of (80K) and can meet the splicing requirement in the space mini-type combined optical filter.

Description

technical field [0001] The invention belongs to the technical field of optical thin films, and in particular relates to a 3.50-3.90 μm mid-wave infrared micro-filter and a preparation method thereof. Background technique [0002] At present, in the spatial micro-combination filter of the remote sensing detection system, a key filter that meets the following requirements is urgently needed: (1) high transmittance in the 3.50-3.90 μm spectral band; (2) 0.80-3.30 μm and The 4.10-5.50μm spectral band has the effect of suppressing optical signals, so the wide cut-offs are at 0.80-3.30μm and 4.10-5.50μm spectral bands to reduce the influence of signal noise; (3) It can be used at low temperature (80K); (4 ) The size of the substrate is small, the angle between all the surfaces of the substrate is a right angle, there is no chamfer, and the film layer does not produce film quality problems such as filming or filming when splicing, so as to meet the needs of micro-combined filters i...

AI Technical Summary

Problems solved by technology

However, the mid-wave infrared filter disclosed above has a relatively narrow cut-off width, which cannot meet the needs of medium-wave infrared filters with high transmittance in the 3.50-3.90 μm spectral band and wide cut-offs in the 0.80-3.30 μm and 4.10-5.50 μm spectral bands. At the same time, the existing mid-wave infrared filter is mainly formed by two kinds of oxides with less difference between high and low refractive index, which has the characteristics of more film layers and large film stress, so it is coated on the micro substrate There will be problems such as film breakage and filming, which cannot meet the splicing and low-temperature use requirements in the space micro-combination filter of the remote sensing detection system

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