High repetition rate laser pulse induced damage in KTP crystal: Gray-tracking and catastrophic damage

The evolution of gray-tracking damage due to high repetition rate laser pulses was experimentally studied. “Dark track” owing to Ti3+ + O2− centers induced by multi-photon absorption was found on the damaged KTP crystal. Moreover, the accumulative process of gray-tracking was simulated through iterating the equation of the number of color centers produced during an arbitrary laser pulse and the method for decreasing gray-tracking based on the simulated results is proposed. The color center model in combination with broken bonds model successfully explains the catastrophic damage, and the hole-like damage pattern can be interpreted by the pressure distribution of laser-supported detonation wave (LSDW).