| 摘要 |
<p>PROBLEM TO BE SOLVED: To appropriately monitor the output of higher harmonics without reducing the output of the higher harmonics that are obtained as effective laser beams and to reduce the number of parts for cost reduction. SOLUTION: When deep ultraviolet laser beams that are higher harmonics are emitted from an emitting surface 28a of a nonlinear optical element 28, a portion of the beams is reflected by the surface 28a, passes through one side surface 28c and is emitted outside the element 28. The strength of the emitted beams is detected by a photodetector 40. Then, laser control such as laser output automatic control is conducted in accordance with the detected signals from the photodetector 40.</p> |
