| Polarizer is an important device of optical modulator. It is widely used in laser action technique, optical information processing, and image-forming system, etc. It can transform non-polarized-light into linearly, circularly and elliptical polarized light, or transform them each other. With the development of modern optics, especially from 1960s'-the first laser appeared, prism-type polarizer becomes an important polarizer in laser polarization technology.Today, polarizer used frequently and of excellent performance are polarizing prism and beam splitter prism, which are made by Iceland. Iceland has excellent properties, and the polarizer made by it can be used in spectrum range from 230nm to 2800nm. Because of its dispersion, technical parameters of polarizer are influenced by wavelength. Many parameters are used to describe their performance, for example transmission ration, extinction ratio, angle of view field and splitting angle, etc. Those parameters' spectral character has been partially researched recently, but the research is not systemic and intensive. Researches of spectral character of prism-type polarizer of this article fix attention on:(l)The law that wavelength influenced on splitting angle of beam splitting prism and its symmetry. Applications of beam splitter prism used in modern optics are summed up and some classical examples are given. And the influence of spectral character of splitting angle on image-forming system is researched.(2) Angles of view field of two directions are compared. And spectral character of them is analyzed. The conclusion is given that the azimuth of polarizing prism should be adjusted for practical demands.(3) Multiple-beam interference of polarizing prism is analyzed using layer optics theories. Phenomena of interference of Glan-prisms are very visible and their cementing layer is air-layer. And spectral character of their transmission ratio is researched academically and experimentally.(4)The influence of frustrated total internal reflection (FTIR) on extinction ratio isresearched for the first time. Transmission of ordinary light and influence of glue refracting index, gas thickness and wavelength on it are researched based on FTIR theory, which are approved by experiments.It can be approved that technical parameters of prism-type polarizer changed along with incident wavelength by theory and experiments. Wavelength is an important factor influenced on performances of polarizer.The main innovations of this article are analyzing the influence on image-forming system of spectral character of splitting angle, using thin film optics to analysis the influence of multiple-beam interference on transmission ration, introducing FTIR of thin film optics to analysis of extinctive ratio for the first time, systemic studying mutative law of primary parameters changing with wavelength. |
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