Measurements of heating and energy storage in flashlamp-pumped Nd:YAG and Nd-doped phosphate laser glasses

The energy stored and the heat generated in flashlamp-pumped Nd:YAG and six different commercially available Nd-doped phosphate glasses have been experimentally measured. It is found that the normalized heating parameter chi, defined as the heat deposited per unit stored energy, is 1.5-2 times the value expected from the known spectroscopy of the Nd ions in these hosts and the emission spectrum of Xenon flashlamps. The heat sources in Nd-doped glasses are discussed. Using a theoretical model, the influence of Nd concentration, flashlamp pulse length, and current density on chi are calculated, and the effects of chi on practical laser design are pointed out.