| 摘要 |
PURPOSE:To obtain a titled body which can be formed easily by a simple constitution by forming a phase difference of lambda/n on a reference optical path, or a composite optical path of a testing optical path and the reference optical path. CONSTITUTION:A reflecting surface of a fixed reflecting body M1 is constituted of two parallel flat reflecting surfaces having a step difference. When a reference light B1 and a testing light B2, which have an optical path difference of lambda/4 are synthesized, two kinds of interference fringes are formed with a phase difference of lambda/4 in a photomultisensor 4. When an optical path of a reflecting surface of a moving reflecting body M2 of a sample W1 and a half mirror 3 is (a), if an optical path of one reflecting surface of the fixed reflecting body M1 and the half mirror 3 is (a), as well, the interference fringe annihilates. The optical path length to the other reflecting surface becomes (b), therefore, an interference fringe formed by passing through at least the optical path of (b) is obtained on the half surface of the photomultisensor 4. |
