| 摘要 |
PURPOSE:To easily control a laser and also to reduce a cost of a beam sorce, by using a semiconductor laser which has stabilized oscillation frequency, and measuring a graduating line interval of a diffraction grating in accordance with an interference pattern moving method. CONSTITUTION:A beam of a semiconductor laser 1 is made incident to a diffraction grating 4 through a lens 3, and a higher diffracted beam is made to form an image on a slit 10 and a wave surface split mirror 11 by a lens 5. The wave surface-split beams are detected by detectors 8, 9, a heat sink 2 is controlled so that the ratio of its outputs becomes constant, by a circuit 13, and oscillation frequency of the laser 1 is stabilized. On the other hand, a lower diffracted beam is made incident to a beam splitter 21 through a lens 6 and a slit 7. One beam and the other beam generate an interference pattern on a detector 25 after it has been reflected by a fixed mirror 22, and after it has been reflected by a reflector 23 and a fixed mirror 24 on a moving base 26, respectively. The line graduating moving base 26 is controlled through a counter 28 and a linear motor 27 in accordance with the number of moving lines. In this way, the beam source is controlled easily and also its price is reduced. |
