发明名称 |
Optical element made from fluoride single crystal, method for manufacturing optical element, method for calculating birefringence of optical element and method for determining direction of minimum birefringence of optical element |
摘要 |
The present invention provides a method for calculating the birefringence of an optical element and selecting the direction of minimum birefringence in the optical element. A material for manufacturing the optical element is a fluoride single crystal with a birefringence value that is reduced compared to conventional materials. The fluoride single crystal is cut from a fluoride single crystal ingot obtained by crystal growth so that the {111} crystal planes are two parallel planes, after which the optical performance is improved by subjecting this material to a heat treatment. The birefringence of the optical element is calculated by converting known piezo-optical constants in a specified three-dimensional orthogonal coordinate system for the optical material into piezo-optical constants in an arbitrary three-dimensional orthogonal coordinate system. The amount of change in the refractive index DELTAn1 of the optical material in a first direction along the direction of one coordinate axis of the arbitrary three-dimensional orthogonal coordinate system, and the amount of change in the refractive index DELTAn2 of the optical material in a second direction which is perpendicular to the first direction are calculated using a uniaxial stress that is applied to the optical material along the first direction and the piezo-optical constants in the arbitrary three-dimensional coordinate system. The amount of birefringence as seen from a third direction perpendicular to the first direction and the second direction is determined in the arbitrary three-dimensional orthogonal coordinate system by determining the difference between the amount of change in the refractive index DELTAn1 and the amount of change in the refractive index DELTAn2.
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申请公布号 |
US2001024314(A1) |
申请公布日期 |
2001.09.27 |
申请号 |
US20000748195 |
申请日期 |
2000.12.27 |
申请人 |
NIKON CORPORATION |
发明人 |
SAKUMA SHIGERU;TAKANO SHUUICHI |
分类号 |
G02B1/02;G02B5/30;G03F7/20;(IPC1-7):G02F1/00;G02F1/03;G02F1/07 |
主分类号 |
G02B1/02 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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