| 摘要 |
PURPOSE:To attain ease of control of luminous amount returned to a light source by making a linear elliptic polarized converting phase plate whose optical axis is tilted by a required angle to a plate face freely turnable around a normal drawn on the plate face and providing a polarized light beam splitter with the light source. CONSTITUTION:The optical axis Z of the phase plate 8 is tilted by a required angle (0<theta<90 deg.) to the plate plane so as to be turned around the normal N drawn on the plate plane. In turning the phase plate 8 around the plate face normal N in this way, the angle between the polarized direction of the diffracted light and the crystal axis of the phase plate 8 is changed and the phase difference GAMMA is changed without changing the optical path at all. The polarized beam splitter 4 is provided between the linear elliptic polarized phase plate 8 and the light source is provided in this way, that is a 1/4 wavelength plate 5 as shown in the figure is replaced, by controlling the luminous amount returned to the semiconductor laser 1. |
