Continuous wave and passively Q-switched Nd:YAG laser with a multisegmented crystal diode-pumped at 885  nm

Mitigation of thermal effects in a 1064 nm Nd:YAG laser is demonstrated through the combination of a multisegmented crystal rod and upper laser level pumping by diode at 885 nm toward optimizing the generated beam profile. Continuous wave (cw) and passively Q-switched operation is demonstrated obtaining 7.5 W and 2 mJ at 100 Hz, respectively, with excellent beam quality. Comparison with a conventional uniform Nd:YAG rod reveals improvements of up to 64% in optical conversion efficiency and 67% in output power for retaining the beam quality. Thermal-lensing measurements validate the improved thermal management in the multisegmented crystal in conjunction with M-square values better than 1.3.