| 摘要 |
<p>A temperature of a semiconductor laser (1) and that of a semiconductor laser (9) are changed approximately 3°C from a temperature at which a laser light source is normally used, at the time of having the laser light source in a standby status. The wavelengths of the laser beams generated by the semiconductor lasers (1, 9) change approximately 0.3nm by a temperature change of approximately 3°C. Though such change has almost no effect on an optical fiber amplifier (2) and an optical fiber amplifier (10), conversion efficiency of each wavelength converting element in a wavelength converting optical system changes, and in particular, almost no extreme ultraviolet ray is generated. Therefore, the wavelength converting element is not damaged even laser beams are left entering the wavelength converting optical system. Thus, a method for having the laser light source in the standby status, by which a startup time of the laser beam light source can be shortened, is provided.</p> |
