HIGH-AVERAGE-POWER 1-MU-M PERFORMANCE AND FREQUENCY-CONVERSION OF A DIODE-END-PUMPED YB-YAG LASER

Using a diode-end-pumped technology, a Yb:YAG laser capable of deliver ing up to 434 W of CW power has been demonstrated. The system incorpor ates a unique composite rod design which allows for high-average-power operation while simultaneously suppressing parasitic oscillations, Mo deling and experimental data to support the quenching of parasitics ar e discussed. Beam quality measurements for CW operation with several c avity configurations are presented. In particular, beam quality measur ements at 340-W CW yielded a beam quality factor of M-2 = 21. Predicti ons of a quasi-three-level model are compared with the experimental da ta for several output coupler reflectivities. An observed dependence o f the cavity mode fill as a function of output coupler reflectivity is discussed. Employing a single acoustooptical switch, the system was Q -switched at 10 kHz and generated output powers up to 280 W with a mea sured beam quality of M-2 = 6.8 at 212 W. With an external dual-KTP cr ystal configuration, the Q-switched output was frequency converted to 515 nm and produced up to 76 W at 10 kHz in a 30-ns pulse length.