On the Mechanism of Limitation of the Frequency-Energy Characteristics of Metal Vapor Lasers

Electrophysical processes in the discharge circuit of a pulsed metal vapor laser are analyzed. The greatest attention is paid to the initial period of the discharge development and conditions for the inversion formation. It is shown that the limitation of the frequency-energy characteristics (FEC) of lasing is due to the process of populating the metastable levels of metal atoms on the excitation pulse front and redistribution of the rates of population of the laser levels in favor of metastable ones with an increase in the prepulse electron density. Which of the processes plays a decisive role in limitation of the lasing FEC depends on the electrophysical process in the discharge circuit of the laser, the development of which is significantly influenced by the arrangement of electrodes in the gas-discharge tube (GDT). The arrangement of electrodes in the GDT also determines the conditions for the inversion formation and the choice of the optimal pumping parameters. Technical solutions are discussed under which the pumping efficiency of a copper-vapor laser attains similar to 10%.