Energetic Bessel–Gauss pulses from diode-pumped solid-state lasers

We discuss the generation of Bessel-Gauss pulses directly from a diode-pumped solid-state laser. The laser resonator has a plano-concave configuration with the concave end mirror replaced with a diffractive phase element. As the active material, Nd-doped yttrium lithium fluoride (YLF) and GdVO(4) crystals have been used. The pulsed operation is obtained by passively Q-switching the laser using Cr(4+): yttrium aluminum garnet (YAG) crystals with different unsaturated transmission coefficients. When guiding the pulses out from the resonator through the laser crystal, 5-10 ns long pulses with energies of 40-50 mu J and peak powers on the order of 10 kW are obtained. Even 70 mu J is possible, but this is achieved at the expense of slightly deteriorated beam quality in the far field. (C) 2010 Optical Society of America