| 摘要 |
PROBLEM TO BE SOLVED: To obtain a laser oscillator, provided with an optical resonator constitution for obtaining laser beams with high output and superior in light-gathering characteristics. SOLUTION: This laser oscillator 1 is provided with a stable optical resonator, comprising an output mirror 7 consisting of a pair of plane mirrors of total reflection opposed to each other, positioned on both sides of a discharge area DA, and a rear mirror 9 of a concave mirror. A laser beam extraction hole 11 is formed in the center of the output mirror 7. A laser beam LB in the discharge area DA travels between the two total reflecting mirrors, the output mirror 7 and the rear mirror 9, and further gradually approaches the axis with efficiency and reliability. The laser beam LB is then projected from the small-diameter laser beam extraction hole 11, located in the center of the output mirror 7 through a totally translucent window 13. As a result, a small- diameter laser beam LB with high output and its energy density distributed symmetrically with respect to the axis is obtained. Furthermore, the portions of the discharge area DA where no laser beam LB passes are reduced, and thus the efficiency of conversion into optical energy is enhanced.
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