MULTISPECTRAL INTERFERENCE LIGHT FILTER FOR PROTECTION FROM LASER RADIATION Russian patent published in 2014 - IPC G02B5/28 B82Y20/00 

FIELD: physics.

SUBSTANCE: light filter includes a transparent substrate and three elements deposited thereon, said elements having interference coatings made of alternating layers with high and low refraction indices (BH)^k. In the first element, which is a multilayer interference filter in form of a second-order mirror (λ₀=1565 nm) with high reflection in the 530-540 nm range and maximum transmission in the 470-505 nm and 545-620 nm range, at the filter-substrate and filter-air boundary, there are additional layers of (CH)³ and (CH)² C1.24H. In the second element, which is a long-wave cut-off filter (λ₀=680 nm) with high reflection in the 635-740 nm range and maximum transmission in the 470-620 nm range, situated on the side of the substrate opposite the first element and directly adjacent to it, there are additional layers of 0.5C(CH)⁴ and (CH)³C 0.54H. In the third element, which is a short-wave cut-off filter (λ₀=425 nm) with high reflection in the 380-460 nm range and maximum transmission in the 470-620 nm range and situated on top of the second element, there are additional layers of 0.5 BH(CH)³ and 0.5B.

EFFECT: high filter transparency in the short-wave and long-wave region of the spectrum from the high reflection band while blocking laser radiation with a given wavelength.

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