Surface micro-structuring of Sapphire by a Q-switched DPSS nanosecond pulsed laser

Abstract

Surface micro-structuring on the C-plane of Sapphire was performed by a Q-switched Diode Pumped Solid-State (DPSS) nanosecond pulsed laser. Based on the analysis of the laser energy intensity under the varying machining parameters, the formation mechanism and the characteristics of the fabricated microstructure are investigated. The results show that the cumulative laser energy density is in a linear relation with the number of the scanning times and the pulse energy while in an exponential relationship with the overlapping rate of the ablation points, and the high laser energy results in the removal of the material around the laser spot to form a grid-type surface. By changing the overlapping rate and the pulse energy, the groove-type or the grid-type microstructure can be obtained. However, to reduce the thermal damage of the machined surface and to increase the surface height consistency, the processing power and the scanning times should be coordinated. The achieved results indicate the feasibility of the nanosecond pulsed laser in high-efficiency surface micro-structuring of Sapphire.