| 摘要 |
A single interferometer system (20) which simultaneously measures linear and angular displacement of a movable plane mirror (90) employs a frequency stabilized laser (10) which emits an input beam (12) comprised of two linear orthogonally polarized components which may or may not be of the same optical frequency. The input beam (12) is incident on a beamsplitter (14) which transmits a beam (16) and reflects a beam (15), with the reflected beam (15) being reflected off a mirror (18) to form a beam (17) which is parallel to but spatially offset from beam (16). Beams (16) and (17) are incident on interferometer (20) and are used to measure linear and angular displacement, respectively, using a polarization beamsplitter (80), prism (82), retroreflector (81) and quarter phase retardation plate (88). A phase meter/accumulator (99) extracts any phase change and provides an output (100) which is directly proportional to the linear displacement of the movable mirror (40) for beam (167) and another phase meter/accumulator (109) extracts any phase change and provides output (101) which is directly proportional to the angular displacement of the movable mirror (90). The movable mirror (90) is affixed to the stage whose relative position and angle is being measured.
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