Laser Damage Threshold of Ceramic YAG

Bulk laser damage thresholds of doped and undoped ceramic Y3Al5O12 (YAG) materials are reported. These materials were found to resist 100 J/cm2, 4-ns pulses at 1.064 µm wavelength. Single-crystal YAG materials of similar composition yielded similar damage thresholds. Hence, ceramic microstructure does not contribute to lower damage threshold. Beam-size dependence of damage threshold fluence was also studied by repeating the experiment using a lens with a longer focal length. The evolution of damage probability with laser fluence was found to strongly depend on the beam diameter; however, damage threshold was not found to vary significantly with beam diameter.