[24p-E106-1~18] 3.7 Laser processing

[24p-E106-14] Effects of the laser intensity ramps on ultrafast laser drilling on transparent materials

〇Dai Yoshitomi¹, Hideyuki Takada¹, Yohei Kobayashi², Aiko Narazaki¹ (1.AIST, 2.ISSP Univ. Tokyo)

Keywords:laser, laser processing, femtosecond laser

We developed an intensity modulator with a modulation frequency up to 500 kHz for a 1-MHz pulse train with the aim of the optimization of ultrafast laser drilling by changing the relative intensities of the irradiated pulses. The irradiation of two ramp patterns (intensity increasing / decreasing) on silica and sapphire substrates resulted in the statistical difference in the ablation depths between two patterns. It is attributed to the reduction of ablation threshold after the onset of the initial damage.