Since copper vapor lasers were first reported in 1966, they have suffered from discharge contamination due to outgassing of materials at high temperatures. To remove impurities, a flowing buffer gas is normally used, making a vacuum and gas handling system necessary. A sealed copper vapor laser tube has been developed. Made from metal, glass and ceramic, it features permanent hard seals at electrodes and windows, making the tube rugged and allowing long shelf and operating lives. The first tube in the series, the XL7000, is still on life test and has reached over 1200 operating hours with many thermal cycles.
Graeme L. Clark,
Ewan S. Livingstone,
"Sealed copper vapor laser tube", Proc. SPIE 2118, Gas, Metal Vapor, and Free-Electron Lasers and Applications, (25 May 1994); doi: 10.1117/12.176671; https://doi.org/10.1117/12.176671