Efficient self-seeding of a pulsed Ti3+:Al2O3 laser

We describe the design considerations and operating characteristics of a compact, widely tunable, narrow-linewidth, megawatt-class pulsed laser system based on Ti(3+):Al(2)O(3) (Ti:sapphire) pumped by the second harmonic of a 1.06-microm Nd:YAG laser. The system delivers 10 mJ in a 5-ns near-transform-limited single-longitudinal-mode (SLM) pulse with a threshold of 20 mJ and a slope efficiency greater than 40%. By the technique of self-seeding, in which a portion of the gain medium's spontaneous fluorescence is coupled back to the laser cavity, SLM operation may be obtained across the entire gain profile of Ti:sapphire with a minimum number of optical components and without external seeding.