| 摘要 |
<p>PROBLEM TO BE SOLVED: To stably output the higher harmonic of high output even though the temperature of a nonlinear optical crystal rises. SOLUTION: Light emitted from a laser device constituted of 11 to 13a and 13b is made incident on a second harmonic crystal 18a, and converted to a second higher harmonic. The second higher harmonic is made incident on a fourth higher harmonic crystal 18b, and converted to a fourth higher harmonic. Light outputted from the fourth harmonic crystal 18b is made incident on scanning mirrors 2a and 2b, the mirrors 2a and 2b are driven in accordance with a marking graphic / a character pattern, and a specified graphic / the character pattern are draw on a work W. A higher harmonic light beam outputted from the crystal 18b is detected by a detector 22, and a control circuit 23 controls the angle of the crystal 18b with respect to the optical axis of an incident laser beam by a crystal driving mechanism 24 so that the higher harmonic light beam becomes maximum.</p> |
