Optical system, exposure system, and exposure method
First Claim
1. An optical systemcomprisinga birefringent optical rotator which is made of an optical material with linear birefringence and optical rotatory power, an optic axis of the birefringent optical rotator is arranged substantially in parallel with an optical axis of the optical system, whereina beam bundle in a substantially circular polarization state is incident to the birefringent optical rotator,the birefringent optical rotator is located at a position where a beam bundle of substantially spherical waves is incident thereto, andthe birefringent optical rotator includesa required thickness for converting a beam bundle in a peripheral region of the incident beam bundle into a beam bundle in a substantially linear polarization state of substantially circumferential vibration in a lens aperture,a first optically transparent member made of an optical material with clockwise optical rotatory power, anda second optically transparent member made of an optical material with counterclockwise optical rotatory power.
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Abstract
An optical system is able to achieve a substantially azimuthal polarization state in a lens aperture while suppressing loss of light quantity, based on a simple configuration. The optical system of the present invention is provided with a birefringent element for achieving a substantially circumferential distribution or a substantially radial distribution as a fast axis distribution in a lens aperture, and an optical rotator located behind the birefringent element and adapted to rotate a polarization state in the lens aperture. The birefringent element has an optically transparent member which is made of a uniaxial crystal material and a crystallographic axis of which is arranged substantially in parallel with an optical axis of the optical system. A light beam of substantially spherical waves in a substantially circular polarization state is incident to the optically transparent member.
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Citations
18 Claims
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1. An optical system
comprising a birefringent optical rotator which is made of an optical material with linear birefringence and optical rotatory power, an optic axis of the birefringent optical rotator is arranged substantially in parallel with an optical axis of the optical system, wherein a beam bundle in a substantially circular polarization state is incident to the birefringent optical rotator, the birefringent optical rotator is located at a position where a beam bundle of substantially spherical waves is incident thereto, and the birefringent optical rotator includes a required thickness for converting a beam bundle in a peripheral region of the incident beam bundle into a beam bundle in a substantially linear polarization state of substantially circumferential vibration in a lens aperture, a first optically transparent member made of an optical material with clockwise optical rotatory power, and a second optically transparent member made of an optical material with counterclockwise optical rotatory power.
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14. An. optical system comprising
a birefringent optical rotator which is made of an optical material with linear birefringence and optical rotatory power, an optic axis of the birefringent optical rotator is arranged substantially in parallel with an optical axis of the optical system, and a projection optical system that forms an image of a first plane on a second plane, wherein a beam bundle in a substantially circular polarization state is incident to the birefringent optical rotator., the birefringent optical rotator is located at a position where a beam bundle of substantially spherical waves is incident thereto, the birefringent optical rotator includes a required thickness for converting a beam bundle in a peripheral region of the incident beam bundle into a beam bundle in a substantially linear polarization state of substantially circumferential vibration in a lens aperture, the projection optical system is arranged to be substantially telecentric on a second plane side, and the birefringent optical rotator is located in an optical path that is substantially telecentric on the second plane side.
Specification