| 摘要 |
PURPOSE:To eliminate the need for a quarter-wavelength plate and facilitate an optical axis adjustment and to use laser light which has two polarized light components by transmitting the P polarized light component of the laser light and reflecting the S polarized light component, and diffracting the transmitted light by an acousto-optic element. CONSTITUTION:The laser light 30 is made incident on a polarization beam splitter 20, which transmits its P polarized beam 31 and reflects its S polarized beam 32. The beam 32 passes through the acousto-optic element 21 to become diffracted light 33, which is reflected by a mirror 24 and transmitted through the 2nd polarization beam splitter 25 as the P polarized light. The beam 32 becomes diffracted light 34 through the 2nd acousto-optic element 27 and the light is reflected by the beam splitter 25 as the S polarized light, thus obtaining two light beams 35 having a slight difference in frequency. Therefore, no quarter-wavelength plate is required and temperature dependency is eliminated; and the number of optical system parts is small, the optical path is easily adjusted, and the incident laser light having the P and S polarized light components is usable.
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