Title:
直交に直線偏光した光ビームを発生させるための装置
Document Type and Number:
Japanese Patent JP4149704
Kind Code:
B2
Abstract:
The present invention relates to apparatus for providing orthogonally polarized light beams for use in precision metrology applications such as in the measurement of length or length changes using interferometric techniques. An input beam is introduced to a multifaceted anisotropic optically active acousto-optical crystal for travel through an interactive region where it experiences two acoustic beams that diffract it via small angle Bragg diffraction to form two orthogonally polarized internal beam components that are separated by a small angle of divergence and subsequently become external beam components available outside of the acousto-optical crystal for use in anticipated downstream applications. The acousto-optical crystal preferably is a uniaxial crystal comprising TeO2. The degree of overlap or spatial separation between the energy flux profiles of the orthogonally polarized, external beam components may be controlled by refracting properties of the acousto-optical crystal, its birefringence, the acoustical and optical properties of the acousto-optical crystal, the length of the physical path of travel experienced by the emergent beam through the acousto-optical crystal and external birefringent elements. Thermal compensation may be provided via the control of the frequency of the first and second oscillators and/or the properties of the external birefringent elements.
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Inventors:
Hill, henry allen
Application Number:
JP2001502205A
Publication Date:
September 17, 2008
Filing Date:
May 02, 2000
Export Citation:
Assignee:
Zygo Corporation
International Classes:
G02F1/11; G02F2/02
Domestic Patent References:
| JP50092152A |
Foreign References:
| WO1999023733A1 |
Attorney, Agent or Firm:
Hidesaku Yamamoto