| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive laser optical device which are small in the correction variation of a light quantity. SOLUTION: Return mirrors 20 and 28 are arranged in positions where much of a P polarized light component is reflected in an optical path of the laser optical device. These return mirrors 20 and 28 are subjected to, for example, Cr coating, etc., in such a manner that their reflectivity thereof is <=80%, by which the light intensity of the laser beam is lowered.
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