Energy enhancement of Nd,Sc:YAG crystal in passively Q-switched lasers

We report on the laser performance of Nd,Sc:YAG (yttrium aluminum garnet), for the first time, to our knowledge. In this study, 10 at.% Sc³⁺ ions were doped into the Nd:YAG crystal to form the Nd,Sc:YAG crystal, which improves the saturation flux while nearly maintaining the excellent properties of the Nd:YAG crystal. The continuous-wave (CW) and passively Q-switched (PQS) laser performances of the Nd,Sc:YAG crystal at 1064 nm were investigated. The CW output power reached 4.5 W at the absorbed pump power of 8.07 W, with a slope efficiency of 63.1% and an optical-to-optical efficiency of 55.7%. A stable PQS laser was achieved employing Cr⁴⁺:YAG as a saturable absorber (SA). The maximum average output power attained was 1.84 W, with a slope of 23.5%. The pulse width, pulse energy, and frequency were 17.0 ns, 69.2 µJ, and 26.6 kHz, respectively. Compared to the Nd:YAG crystal, the pulse energy of the Nd,Sc:YAG crystal was enhanced by approximately 1.7 times. These results show that the Nd,Sc:YAG crystal is a promising laser material with larger energy storage capacities, making it suitable for the application of high-energy lasers (HELs) with high repetition rate.