Arc discharges in alkali-earth metal vapors as possible pump sources for YAG:Nd/3+/ lasers

The spectral energy distribution in the region from 500 to 920 nm of radiation from sapphire arc lamps with vapors of the alkali-earth metals K, K+Rb, and Na+K has been measured. It is shown that for a specific choice of vapor pressure the radiation efficiency of these lamps in the absorption bands of the Nd ions in YAG:Nd(3+) crystals is substantially higher than that of Kr arc lamps with analogous discharge-gap sizes for electrical energies up to 1 kW. Optimum parameters for an effective pump source are determined; these include vapor pressures of about 10 to 100 torr and current densities of 30 to 150 A/sq cm for an inner discharge-tube diameter of approximately 4 mm.