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Up to 1 MHz acousto-optics Q-switching operation was obtained in a grazing-incidence Nd:YVO4 laser. At 500 kHz repetition rate, 17.7 W of output power was obtained with 38 W of pump power when 32.4% transmissivity output coupler was used. The beam quality factors were measured as M 2 x < 4 in the x-axis direction and M 2 y < 2 in the y-axis direction. For high sable acousto-optics pulse operation, 5% transmissivity output coupler was used and 9.15 W of output power was obtained at 38 W of pump power. The peak-to-peak instability of pulse amplitude was less than ±3.3% at 489.6 kHz repetition rate.Photograph of oscilloscope traces showing the pulse series at 489.6 kHz

A comprehensive observation of the stimulated Brillouin scattering (SBS) phenomena in a high power nanosecond linearly polarized Yb-doped double-clad fiber amplifier is presented. According to the behavior of SBS, the amplification process is divided into four regions. All the temporal, spectral and power characteristics of SBS in both forward and backward directions in each region are described in detail. Cascaded SBS with up to 30 orders of Stokes waves and 10 orders of anti-Stokes waves is observed. The fiber damage caused by the giant SBS pulses is reported. And the influence of the linewidth, pulse duration, feedback and polarization on SBS is discussed.

A novel side-pumped structure with microlens-free diode arrays and a lensduct was demonstrated. This structure is much more robust and simple than traditional approach of a microlens-conditioned diode arrays with a lensduct. A quasi-CW diode arrays side-pumped KD*P Q-switched Yb:YAG slab laser has been demonstrated. An output energy of ∼10 mJ/pulse with pulse width as short as ∼20ns is obtained at 1-10 Hz repetition rate. To our knowledge, this is the shortest pulse width of Electro-optic Q-switched laser output by using Yb:YAG as the gain medium. Output energy as a function of Yb:YAG absorbed energy

A green laser with output power 15 W at 515 nm is introduced, which was based on an extra‐cavity frequency doubling of a corner‐pumping Yb:YAG slab laser, with pulse repetition rate of 10 kHz and pulse duration of ∼150 ns, using an acousto‐optic Q‐switcher. An LBO crystal was used as nonlinear crystal for frequency doubling in this experiment, which was cut for type‐I non‐critical phase‐matching. The frequency doubling efficiency was 30%. (© 2007 by Astro, Ltd. Published exclusively by WILEY‐VCH Verlag GmbH & Co. KGaA)