| 摘要 |
PURPOSE:To eliminate the need for a quarter-wavelength plate and to use laser light which has two polarized light components by further separating separated P and S polarized light components of he laser light into diffracted light and 0-order light through an acousto-optic element, and detecting their quantities by photodetectors. CONSTITUTION:The P polarized beam 33 of the laser light 32 is transmitted through a polarization beam splitter 20 and the S polarized light beam 36 is reflected; and the two beams are sent out by acousto-optic elements 22 and 25 as 0-order light beams 35 and 37 and diffracted light beams 36 and 38. The beam splitter 25 transmits the beam 36 as P polarized light and reflects the beam 38 to obtain two light beams 39. The 0-order light beams 35 and 37 are detected by photodetectors 23 and 29 to obtain their quantities and a control circuit 30 controls transducers 22 and 28. Therefore, no quarter-wavelength plate is required and temperature dependency is eliminated; and the incident laser light having P and S polarized light components is usable and two mutually orthogonal polarized light beams is equalized at any time.
|
