PURPOSE: To prevent an oscillation wavelength from becoming unstable use to return light, by constituting an isolator of both polarizers whose polarized light direction is different by a prescribed angle, a Faraday rotary element, and a magnet for applying a magnetic field to said element.
CONSTITUTION: A Faraday rotary element 7, and polarizers 8, 8 for inserting and holding it are formed in a square shape and fixed in a cavity in the axial direction of a magnet 9. Also, a plane of polarization of the front polarizer 8, and a plane of polarization of the rear polarizer 8 are in the direction which has been twisted by 45°. By the front polarizer 8, a light beam which has been emitted from a laser becomes linearly polarized light having a plane of polarization in the direction Y, and by the Faraday rotary element 7, the plane of polarization rotates by 45°, and confirms with a plane of polarization which has been set in advance, of the rear polarizer, therefore, the light beam can pass through it. When the return light passes through the rear polarizer 8, it becomes the linearly polarized light which makes an angle of 45° against the axis Y, and when said light passes through the Faraday rotary element 7, it becomes the linearly polarized light having a plane of polarization of 90° against the axis Y, and the plane of polarization becomes the X axis direction. Such the light cannot pass through the front polarizer 8, and the return light is cut off.
SHIRAISHI KAZUO
NISHIKAWA MITSURU
SUMITOMO ELECTRIC INDUSTRIES
| JPS6097305A | 1985-05-31 |
Next Patent: FULL COLOR REPRODUCTION METHOD AND APPARATUS OF CONTINUOUS TONE COLOR IMAGE