Polarization-maintaining semi-transmissive semi-reflective mirror for 45-degree linearly polarized light

Abstract

A polarization-maintaining semi-transmissive semi-reflective mirror for 45-degree linearly polarized light structurally comprises a prism with a small edge angle and an optical film system, wherein the wedge face of the prism and a plane opposite to the wedge face are respectively plated with a first optical film and a second optical film; the first optical film belongs to a reflective film system to which the reflectivity of p light and s light both with the center wavelength of incident laser is 50 percent when the incidence angle is 9 degree; and the second optical film belongs to an anti-reflecting film system to which the transmissivity of the p light and s light both with the center wavelength of incident laser is larger than or equal to 99.5 percent. The semi-transmissive semi-reflective mirror can not only achieve 50-percent transmission and 50-percent reflection of 45-degree linearly polarized light but also enable the transmission light and the reflected light to keep the same polarization state as the incident light, has simple manufacturing technology and low cost, is more suitable for optical systems demanding more on the polarization state of light.

Description

technical field [0001] The invention relates to the design of a beam splitter in an optical system, in particular to a half-transparent half-mirror for maintaining polarization of 45° linearly polarized light. Background technique [0002] The spectroscopic device is an indispensable part of some optical paths, and now the spectroscopic device is mainly realized by polarizing prism or coating process. Polarizing beam splitters use the birefringence effect of birefringent crystals to separate light of different polarization states, which cannot maintain the polarization of reflected light and transmitted light; when the light beam is obliquely incident at a large angle (>15°) In the case of optical thin films, the tangential components of the electric field and magnetic field on each interface are continuous, so that the film system exhibits different effective refractive indices for the p component and s component, and the film system shows strong polarization characteris...

AI Technical Summary

Problems solved by technology

In the past few decades, both at home and abroad have never stopped research on the problem of polarization maintenance of thin films, and have achieved a lot of research results, but there is still a lack of a general method that is generally applicable, and the technology is immature. High difficulty, high cost and high price, cannot be widely used in experiments

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