Surface micro-fabrication of UV transparent materials by laser-induced backside wet etching

Laser-induced backside wet etching of silica glass and sapphire plates was performed by the excitation of a liquid with a ns-pulsed UV excimer laser. Well-defined micropatterns were fabricated without debris and microcrack around the etched area. To understand the etching mechanism, the formation and propagation of shockwave and bubble were monitored by time-resolved optical microscopy at the interface between the silica glass and the liquid during etching process. Transient high-pressure as well as high-temperature generated by UV laser irradiation plays a key role in the etching process.