ABLATION OF AIN CERAMICS BY MULTIPULSED PICOSECOND RADIATION AT WAVELENGTH OF 1078 AND 539 NM

Experimental investigations of AIN ceramic ablation in air by the firs t and second harmonics of picosecond Nd :YAP laser have been conducted . For beam intensity of 10(10)-10(14) W/cm(2), ablation rates, irradia ted zone morphology, and element contents have been studied. Two regim es of ceramic ablation depending on the laser pulse number were found: cracking and removal ceramic grains by first pulses and transition to the evaporation regime for a pulse number greater than or equal to 10 -100. The mechanism of such transition based on laser-induced modifica tion of a ceramic surface layer is proposed. Applications of the devel oped technique to laser drilling and cutting are considered.