Multiwatt compact ceramic Yb:YAG passively Q-switched laser

Thanks to the reduced quantum defect with respect to Nd doped materials, Yb doped crystals are widely employed as laser material in high-power diode-pumped lasers. YAG crystalline matrix, thanks to its remarkable thermo-mechanical properties is particularly suitable for high-power management. Moreover, the relatively broad fluorescence bandwidth of Yb:YAG allows ultrashort pulse generation, even at very high average power. Ceramic Yb:YAG has also been investigated in recent years since it promises cheaper devices and larger volume fabrication, while maintaining the attractive properties of the single crystal. In this work, we investigated the growth, spectroscopy and laser operation of two Yb:YAG ceramic samples. We demonstrated a combination of average power (4.4 W), pulse duration (~7 ns), peak power (~12 kW) and repetition rate (~50 kHz) in Passive Q-switching (PQS) operation that set the state of the art for medium power Yb-doped solid-state lasers and can be very attractive for many material processing applications.