| 摘要 |
PURPOSE:To stably operate for a long time by disposing a slender shielding cylinder around an optical axis, suppressing a phenomenon of gathering dusts, thereby reducing the decrease in the laser output even when a dust cover is opened in not clean atmosphere. CONSTITUTION:An optical window 2 and a reflecting mirror 3 provided at both ends of a laser tube 1 are coupled by 1a dust cover 4, sealed by O-rings 5, a shielding cylinder 6 is disposed coaxially in the cover 4, and secured by fittings 7. One end of the cylinder 6 opposed to the window 2 is obliquely cut at the port 6a to be directed upward. The flow of dusts produced by convection does not cross the cylinder 6 due to the presence of the cylinder 6, the dusts are not trapped by a strong internal laser light to getter at the optical path. The window 2 is, once heated, not adhered with dusts, but the dusts pass therearound. |
