Self-pumped phase-conjugate diode-pumped Nd:YAG loop resonator

We demonstrate a self-pumped phase-conjugate diode-pumped Nd:YAG loop resonator. In the injected configuration a maximum phase-conjugate reflectivity of 32 is obtained. The output beam has a pulse shape of ~30 ns , which shows the self- Q -switching ability of the resonator. By use of a low-refractive-output coupler, a self-starting version was produced. The resonator operated in a stable diffraction-limited TEM(00) mode, even with severe intracavity phase aberrations. A maximum energy of 5.5 mJ (2.4% of the energy of the high-brightness stacks that was incident upon the Nd:YAG crystals) in a 20-ns single-longitudinal-mode pulse was measured.