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

Abstract

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 GdVO4 crystals have been used. The pulsed operation is obtained by passively Q-switching the laser using Cr4+: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 μJ and peak powers on the order of 10 kW are obtained. Even 70 μJ is possible, but this is achieved at the expense of slightly deteriorated beam quality in the far field.