| 摘要 |
PROBLEM TO BE SOLVED: To improve a quality of exposure light and a processing quality, by always fulfilling all specifications demanded by wave front control including beam size, laser output efficiency and spectrum linewidth. SOLUTION: The narrow band laser device includes a laser for generating a laser beam by discharge exciting a laser medium, a narrow band module 6 having a narrow band element for narrowing a band of the laser beam received from the laser and a wave front adjusting means for correcting and outputting the wave front of the incident laser beam, and a power lock control means 40 for controlling the excitation intensity to provide a constant laser output for power lock control. The laser device further comprises a linewidth detection means 15 for detecting a spectrum linewidth of the laser beam, a beam size detection means 14 for detecting a size of the laser beam, an excitation intensity detection means 40 for detecting the excitation intensity, and a control means 40 for controlling the wave front adjustment means in such a manner that the detected spectrum linewidth, beam size and excitation intensity fall in their predetermined specification ranges. |
