Sub-Nanosecond Passively Q-Switched Yellow and Orange Raman Lasers

Sub-nanosecond high-peak-power passively Q-switched yellow and orange lasers are compactly developed using a near-concentric resonator with intracavity-stimulated Raman scattering (SRS) as well as second harmonic generation (SHG). The fundamental wave is generated from an a-cut Nd:YVO4 crystal. The Stokes wave for an SHG yellow (579 nm) or orange (589 nm) laser is generated from a Np-cut potassium gadolinium tungstate (KGW) with the Ng or Nm axis parallel to the c-axis of Nd:YVO4 crystal. The optimal cavity length is systematically explored in a near-concentric configuration to achieve sub-nanosecond high-peak-power pulses. The shortest pulse widths for the yellow and orange output pulses are down to 0.67 ns and 0.70 ns, respectively. The highest peak powers for the yellow and orange output pulses are up to 176 and 138 kW, respectively.