Experimental investigation and numerical simulation of the spatio-temporal evolution of the laser pulses in Q-switched Nd:YAG-lasers

Summary form only given. We report on the two-dimensional measurement of the spatio-temporal dynamics of the pulse formation in Q-switched Nd:YAG-lasers. In our investigation we compare two different resonators. A positive-branch confocal unstable resonator with a gaussian variable reflectivity outcoupling mirror provides 7 ns pulses in a 8 mm beam with a pulse energy of up to 650 mJ and a near flat-top transverse intensity distribution. The second resonator consists of a stable cavity and a resonator-internal telescope. This system provides 10 ns pulses in a 4 mm beam and a pulse energy of 90 mJ. With an additional amplifier stage the pulse energy is increased up to 350 mJ. An internal mode-aperture discriminates high-order transverse modes, leading to a nearly gaussian transverse intensity distribution.