A high peak power passively Q-switched Nd:YAG dual-rod 532 nm laser based on LED side pumping

In this paper, we present a high peak power passively Q-switched intracavity frequency-doubled green laser based on an efficient LED-pumped Nd:YAG dual-rod laser module. In quasi-continuous wave (QCW) running operation, the average output power of the fundamental laser at 1064 nm reaches as high as 20.98 W at a repetition rate of 50 Hz with a maximum single pulse energy of 419.6 mJ, corresponding to a maximum optical conversion efficiency of 38.8% and a slope efficiency of 41%. Under passively Q-switched conditions, the maximum output peak power at 1064 nm is 1.4 MW with a pulse duration of 88 ns. Through fine-tuning the incident angle of the KTP crystal to satisfy non-critical phase matching conditions, over 2 W of 532 nm average power is generated with a corresponding pulse duration of 68 ns, resulting in a peak power of 0.61 MW for the 532 nm laser. To the best of the authors’ knowledge, this represents the highest average power QCW 1064 nm laser and the highest peak power passively Q-switched intracavity frequency-doubled 532 nm laser based on LED pumping reported to date.