Diode-pumped Nd:YAG laser producing 122-W CW power at 1.319 μm

A high-power diode-pumped Nd:YAG laser oscillating at a wavelength of 1.319 mu m is reported. A 122-W CW laser beam with an M2 factor of 35 has been achieved with an optical efficiency of 19.6%, The Lasing characteristics, including thermal lensing, at 1.319 mu m are compared with those at 1.06 mu m. Under lasing conditions, the focal length of thermal lensing at 1.319 mu m decreases by 25% and increases by 15% at 1.06 mu m with respect to the nonlasing conditions. Based on the experimental results, the heat dissipation in an Nd:YAG rod is discussed with reference to nonradiative transitions from the upper laser level.