Fabrication of precision microholes and structures with smooth surfaces by a high repetition rate femtosecond laser

Precision micro holes and structures with smooth internal surfaces are introduced. We adopted a high repetition rate femtosecond laser to form optically damaged structures inside a silica glass. The glass is dissolved by HF aqueous solution after the laser irradiation. Through this process, we could obtain micro structures with smooth internal surfaces. We investigated the effects of laser repetition rate on surface roughness. It is suggested that one of the causes increased hole surface roughness is the increase in the defects by the laser irradiation.