| 摘要 |
PURPOSE: To make the structure of an interferometer compact by providing a mirror unit with two plane mirrors of different sizes opposing to each other to be rotationally movable in such a manner that the rotational axis is set in the same plane as the center plane of a beam divider. CONSTITUTION: A beam hitting a beam divider 1 is divided into a reflection component and a transmission component, reflected from plane holding mirrors 21, 22 and then passes through a hollow axis (6) at angles α, -α to a rotationally axial line 61. Both beam halves hit a small plane mirror 51 with a normal line inclined at an angle β to the axial line 61 and enters a mirror unit 50 at the center. Both beam halves, after reflected to a large plane mirror 52 followed by fixed plane mirrors 71, 72, vertically hit them. The beam reflected from the mirrors 71, 72 are reversely moved in the same passage, combined in the divider 1 and focused to a detector 4 with an optical element 3. When the unit 50 is rotationally moved, the length of the beam passage in which the beam halves pass is changed to be shorter at one side and longer at the other side, its difference being periodically and continuously changed.
|
