| 摘要 |
A laser interference device (10) comprising a first beam splitter (22) dividing a laser beam from a light source (3) into a first beam (L2) and a second beam, a second beam splitter (24) dividing the second beam into a third beam (L1) and a fourth beam (L3) and allowing reflected beams incident therein in the reverse directions of the beams (L1, L3) to outgo in the reverse direction of the second beam, and beam selection parts (50, 51, 60, 66, 68) selecting one of the reflected beams of the third and fourth beams (L1, L3) allowed to outgo from the second beam splitter (24) in the reverse direction of the second beam which is synthesized with the reflected beam of the beam (L2) incident in the first beam splitter (22) in the reverse direction of the first beam (L2). |
