Experimental development of a monolithic passively Q-switched diode-pumped Nd:YAG laser

The development of a passively Q-switched Nd:YAG laser is described in quite some experimental detail involving 3 pump diode arrays (70 W, 300 W, 600 W). Emphasis is set on the influence of pump beam profile and optimum fiber diameter on achievable pulse energies in the chosen case of fiber-coupling for the pump radiation (adjustable parameters: initial transmission, mirror reflectivity and resonator length; this work having been preceded by numerical simulations not covered in this paper). The coupling optics plays a major role on basis of variable fiber-lens distance and focal length in the formation of single or even multiple pulses. Finally, a monolithic demonstrator is presented which could be employed for applications like the induction of chemical reactions in general, i.e. ignition, for instance, in more detail. Stable ns-operation with emitted pulse energies up to 15 mJ could be achieved.