A novel scheme was developed for a diode-pumped passively Q-switched Nd:YVO4/KGW Raman laser at 589 nm with a diode-to-orange conversion efficiency reaching 11.4%. The compact near-concentric cavity was designed to achieve the criterion of good passive Q-switching and to contain a coupled resonator for intracavity stimulated Raman scattering (SRS) and second harmonic generation (SHG). The dependence of the output performance on the initial transmission of the saturable absorber was explored in detail. Furthermore, the output performance was studied by considering the influence of the pump-to-mode size ratio. By using an initial transmission of 50%, the highest pulse energy and peak power were 110 μJ and 118 kW, respectively, at a pump duration of 40 μs and a pump frequency of 10 kHz.

Efficient diode-pumped passively Q-switched Nd:YVO4 yellow and orange lasers are developed with the pulse pumping scheme and the intracavity stimulated Raman scattering (SRS) and second harmonic generation (SHG). A Np-cut KGW is exploited in the SRS process to generate the yellow 579 nm laser or the orange 589 nm laser in a selectable way. The high efficiency is achieved by designing a compact resonator to include a coupled cavity for intracavity SRS and SHG and to provide a focused beam waist on the saturable absorber for reaching an excellent passive Q-switching. The output pulse energy and peak power can reach 0.08 mJ and 50 kW for the orange laser at 589 nm. On the other hand, the output pulse energy and peak power can be up to 0.10 mJ and 80 kW for the yellow laser at 579 nm.