Micromachining Characteristics of Sapphire with Fifth HG Nd:YAG Laser
In order to reduce the thermal influences in laser machining of sapphire surface, effects of a short-pulse ultra-violet laser were investigated. For the UV laser, the Fifth harmonic generation (Fifth HG) wave of an Nd:YAG laser (wavelength:213nm) was utilized. Significant reduction of thermal damages on the surface was demonstrated with the Fifth HG pulses compared to longer wavelengths of the Nd:YAG laser. It was shown that the control of depth of bottom surface with reduced thermal influences was possible in lower fluence cases(less than 40 J/cm2) with a homogenized beam and smooth surface roughness Ra < 200nm was obtainable.
Dongming Guo, Tsunemoto Kuriyagawa, Jun Wang and Jun’ichi Tamaki
T. Noji et al., "Micromachining Characteristics of Sapphire with Fifth HG Nd:YAG Laser", Key Engineering Materials, Vol. 329, pp. 589-594, 2007