Highly damage-resistant Mo mirror for high-power TEA CO(2) laser systems

A high-purity molybdenum (Mo) mirror was developed by an electron-beam melting method (e.b.m. Mo mirror). For the high-power TEA CO(2) laser, the e.b.m. Mo mirror has two to four times higher surface damage threshold than that of an Au-coated glass mirror and three times longer lifetime than that of a powder metallurgy Mo mirror (p.m. Mo mirror) when laser energy density lower than 60 J/cm(2) was irradiated with a 0.5-pps repetition rate. It was found that the difference between the e.b.m. Mo mirror and the p.m. Mo mirror at the laser-damage threshold was due to the fine surface without voids and the small amount of impurities.