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公开(公告)号:EP0158505A2
公开(公告)日:1985-10-16
申请号:EP85302338.0
申请日:1985-04-03
申请人: TRW INC.
CPC分类号: G01J9/02
摘要: An interferometer, and corresponding method, for use in the measurement and correction of wavefront aberrations in a beam of radiation. The interferometer includes optical elements for generating a reference beam with a known wavefront phase characteristic. The reference beam is recombined with the sample beam, to produce an interference pattern indicative of the phase aberrations in the sample beam as compared with the reference beam. An array of detectors produces electrical signals corresponding to discrete elements of the detected pattern, and an electrical circuit for each elemental detector generates phase correction signals to be applied to a set of movable mirror elements arranged to effect phase changes in the sample beam path. The movable mirror elements adjust the elemental path lengths of the sample beam to yield zero detected phase differences. The mirror elements may be integrated into the interferometer, or may take the form of a deformable mirror used for phase compensation of a light beam. The reference beam in the preferred form of the invention is dithered at a high frequency to minimize the effect of noise, and each electrical circuit includes a synchronous detector to remove the dither-frequency component. In accordance with one disclosed form of the invention, the reference beam is not planar but is aberrated in a conjugate relationship with the radiation beam to be corrected, to provide improved control loop performance.
摘要翻译: 干涉仪和相应的方法,用于测量和校正辐射束中的波前像差。 干涉仪包括用于产生具有已知波前相位特性的参考光束的光学元件。 与参考光束相比,参考光束与采样光束重新组合,以产生指示采样光束中的相位差的干涉图案。 一组检测器产生对应于检测到的图案的离散元件的电信号,并且每个元件检测器的电路产生相位校正信号,以将其施加到被设置为实现样品光束路径中的相位变化的一组可移动镜元件。 可移动镜元件调整样品光束的基本路径长度以产生零检测相位差。 镜元件可以集成到干涉仪中,或者可以采用用于光束的相位补偿的可变形反射镜的形式。 以本发明的优选形式的参考光束以高频抖动,以最小化噪声的影响,并且每个电路包括用于去除抖动频率分量的同步检测器。 根据本发明的一种公开形式,参考光束不是平面的,而是与待校正的辐射束的共轭关系成像,以提供改进的控制环路性能。
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公开(公告)号:EP0158505A3
公开(公告)日:1985-11-21
申请号:EP85302338
申请日:1985-04-03
申请人: TRW INC.
CPC分类号: G01J9/02
摘要: An interferometer, and corresponding method, for use in the measurement and correction of wavefront aberrations in a beam of radiation. The interferometer includes optical elements for generating a reference beam with a known wavefront phase characteristic. The reference beam is recombined with the sample beam, to produce an interference pattern indicative of the phase aberrations in the sample beam as compared with the reference beam. An array of detectors produces electrical signals corresponding to discrete elements of the detected pattern, and an electrical circuit for each elemental detector generates phase correction signals to be applied to a set of movable mirror elements arranged to effect phase changes in the sample beam path. The movable mirror elements adjust the elemental path lengths of the sample beam to yield zero detected phase differences. The mirror elements may be integrated into the interferometer, or may take the form of a deformable mirror used for phase compensation of a light beam. The reference beam in the preferred form of the invention is dithered at a high frequency to minimize the effect of noise, and each electrical circuit includes a synchronous detector to remove the dither-frequency component. In accordance with one disclosed form of the invention, the reference beam is not planar but is aberrated in a conjugate relationship with the radiation beam to be corrected, to provide improved control loop performance.
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