Shift and broadening of emission lines in Nd3+:YAG laser crystal influenced by input energy

Spectroscopic properties of the flashlamp-pumped Nd (3+):YAG laser as a function of input energy were studied over the range of 18-75 J. The spectral widths and shifts of quasi-three-level and four-level inter-Stark emissions within the respective intermanifold transitions of and were investigated. The emission lines of shifted towards longer wavelength (red shift) and broadened, while the positions and linewidths of the transition lines remained constant by increasing the pumping energy. This is attributed to the thermal population as well as one-phonon and multiphonon emission processes in the ground state. This phenomenon degrades the output performance of the lasers.