Experimental Study on Cracks and Chippings during the Ablation of Sapphire Crystal

The experiment research regarding ablating the sapphire substrate by picosecond laser with wavelength of 532nm is presented. The influence of adjusted processing parameters on the cracks and clippings via controlling the variable method is studied. Furthermore, the analysis results shows that the thermal effect of 532nm picosecond laser is obvious, cracks and clippings will appear after only a few pulses of ablation. However, when the laser power decreases to 1.32W, the sapphire is ablated, and the cracks and chippings are significantly reduced. Eventually, a straight round hole with a diameter of 0.3mm that have not obvious cracks and chipping would be processed when the energy was selected near the ablation threshold