| 摘要 |
PROBLEM TO BE SOLVED: To stably measure a displacement amount and a moving amount of a measuring object with a sub-nanometer order or less of precision, without being affected by a disturbance such as air fluctuation and mechanical vibration. SOLUTION: A pulse light is divided into two lights, one thereof is reflected on the measuring object to get incident thereafter into a delay optical path corresponding to one pulse period, the other reaches the measuring object with the one pulse period of lag, after passed through along a reverse direction of the delay optical path in the same optical path, so as to be reflected. An optical phase change generated in accompaniment to the moving of the measuring object is found by bringing the both pulse lights into interference. COPYRIGHT: (C)2007,JPO&INPIT |
