We used 9.9-ns, single-longitudinal-mode, TEM00 pulses tightly focused to an 8-micron
radius spot to measure single-shot and multiple-shot damage thresholds of pure and Nddoped
ceramic Yttrium Aluminum Garnet (YAG), and of pure, Nd-doped, Cr-doped, and
Yb-doped crystalline YAG. By tightly focusing the laser beam, we kept the damage
threshold powers below the SBS threshold, and minimized the effect of self focusing.
The size of the focus spot was measured using surface third harmonic generation.
We found both single-shot and multiple-shot damage thresholds to be deterministic. At
the single-shot damage threshold in YAG, breakdown always occurs on the trailing edge
of the laser pulse. However, for multiple-shot damage threshold, breakdown occurs at the
peak of the nth laser pulse.
Our measured damage thresholds for doped and undoped, ceramic and crystalline
YAG range from 1.1 to 2.2 kJ/cm2. We also report some damage morphologies in