| 摘要 |
PURPOSE:To repeatedly change the light path length of split light without providing a reciprocal movement mechanism, by rotating the optical system having a plurality of reflective surfaces provided on the light path between a beam splitter and a fixed reflective mirror. CONSTITUTION:A beam splitter 11 for splitting incident beam IR into two luminous fluxes, a fixed reflective mirror 12 for reflecting reflected beams from the beam splitter 11 to allow the same to be again incident to said splitter 11 and reflective mirrors 14, 15, arranged on a rotary stand 13 for reflecting transmitted beams to allow the same to be incident to a fixed reflective mirror 16 are provided. Two kinds of beams again incident to the splitter 11 from the fixed reflective mirrors 12, 16 are interfered and the interfered beam IL is allowed to irradiate a specimen. When the rotary stand 13 is rotated to one direction, the light path length between the splitter 11 and the fixed mirror 16 is changed. By this mechanism, the reciprocal movement of an optical system is unnecessary and the light path length of beam split by the splitter can be varied. |
