Surface micromachining of UV transparent materials

A method which utilizes XeCl excimer laser and an absorbing liquid in contact with the material for precise structuring of UV transparent materials is presented. This one step micromachining process enables the fabrication of micro-optical elements with continuous profiles such as Fresnel micro-lenses in CaF2 and quartz with fluences well below the damage threshold of these materials. The roughness of the etched features varies from 10 nm to 3 μm depending on the laser fluence and material. The etch rates of different UV transparent materials (such as CaF2, BaF2, sapphire and quartz) at various laser fluences suggest that several different parameters influence the etching process.