Actively Q-switched self-frequency-doubled Yb:YCOB green laser with output power of a dozen watts

A diode laser (LD) end-pumped acousto-optic Q-switched self-frequency-doubled (SFD) Yb:YCa4O(BO3)3 (Yb:YCOB) pulsed green laser was realized for the first time (to our knowledge), with a maximum average output power of 11.6 W and an optical conversion efficiency of 30.0% from the LD to SFD lasers. The wavelength of the SFD lasers was controlled to be 507 nm for improving quantum efficiency up to 96% and reducing thermal effects. The repetition rates ranged from 20 to 500 kHz, and the maximum pulse energy was 312.0 µJ with a peak power of 4.78 kW at a repetition rate of 20 kHz. This work represents the highest output power in the SFD pulsed lasers and provides an efficient and compact way to generate high-power pulsed green lasers that should have important applications in many aspects, such as ultraviolet (UV) laser generation, laser display, and medical, military, and scientific research.