| 摘要 |
PROBLEM TO BE SOLVED: To provide a heterodyne laser interferometer which can minimize displacement in reference beam and measuring beam due to rotation of stage. SOLUTION: This interferometer system 100, 100A, 400 for measuring displacement along the 1st direction (Z) includes (1) measuring roof-shaped optical parts 104, 404 (e.g., Porro prism) attached to a stage 108 moving along the 1st direction, (2) both (a) a 1st face 105 facing the measuring roof-shaped optical components and (b) a polarizing beam splitter 103 equipped with a 2nd face 109 opposite to the 1st face, (3) 1st wavelength plates 106, 406 located between the measuring roof-shaped optical components and the 1st face of the polarizing beam splitter, and (4) a turnaround optical component 110 located on the opposite side to the 1st face of the polarizing beam splitter. Measuring light path passing through the system comprises only those segments located in the plane demarcated by both the 1st direction and the 2nd direction perpendicular to the 1st direction (Y or X). COPYRIGHT: (C)2006,JPO&NCIPI
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