ABSTRACT
The first mention of the early works with metal vapour lasers generated at the atomic transitions from the resonant to metastable levels can be found in [1-3], which relate to 1965 and 1966. At that time there were great difficulties in the design of high-temperature cavities containing vapours of high-temperature metals, particularly copper and gold. As shown in [4], for the efficient lasing at self-contained transitions of metal atoms it is necessary to achieve densities of 1014-1015 cm-3, which requires reaching temperatures of 1500-1700˚C for gas-discharge tubes.
