| 摘要 |
PURPOSE:To enable a light beam to be split without the use of a special optical part by using a polarization beam splitter for light splitting means and arranging light source means such that the polarization direction of an interferable light beam forms an angle 45 deg. relative to the plane of cross polarization of the polarization beam splitter. CONSTITUTION:A polarization beam splitter has a function to transmit the P wave component of a light beam with an arbitrary polarizing direction through the light beam splitting plane 4 of the splitter and to reflect the S wave component of the light beam by the plane 4. Accordingly, by setting the polarization bearing of the light beam emitted from a light source so as to form an angle 45 deg. relative to the plane of cross polarization of the light beam splitting plane 4, the amplitude ratio of the P wave component to the S wave component split by the light beam splitting plane 4, that is, the ratio of the transmitted light beam to the reflected light beam is represented by sin45 deg.:cos45 deg. = 1:1, resulting in a splitting at the same intensity. For example, a semiconductor laser is used as a laser 1, which is so mounted with an inclination and around the optical axis of a collimator lens 2 that the plane of polarization determined by the structure of the semiconductor laser forms a prescribed angle 45 deg. relative to the light beam splitting plane 4 of an optical part 3.
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