| 摘要 |
A single interferomter system capable of measuring accurately linear displacement and angular displacement simultaneously of a movable plane mirror (90) comprises a source (10) of a frequency stabilized input beam (12), a polarization beamsplitter (80), two quarter-wave plates (88, 108), a mirror (89), and a retroreflector (81), to reflect one polarization component of the input beam (12) twice from the movable mirror (90) to produce a first output beam and to reflect the other polarization component of the input beam (12) twice from the stationary mirror (89) to produce a second output beam. The beamsplitter (80) recombines the output beams into a third output beam having two orthogonally polarized components related to the linear displacement of the movable mirror (90) at the first position. The third output beam is divided into a fourth output beam and a fifth beam parallel to, spatially displaced from, and traveling in the same direction as the input beam (12) and has its polarization components rotated by 90 degrees from the third output beam. The interference between the components of the fourth beam is detected by photodetector (94) and the phase change is extracted from the resultant signal (96, 99) with the measured phase being related to the linear displacement of the mirror (90) at the first position. A second photoelectric detector (194) produces a signal from which the phase change is extracted from the resultant signal (97, 109) with the second measured phase related to the angular displacement of the movable plane mirror (90).
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