Laser-induced front side etching of fused silica with femtosecond laser radiation using thin metal layers

► The laser etching of fused silica with a fs laser allows nm-precision etching with etching depths up to 100 nm. ► Chromium layers work well as laser energy absorber in the laser etching process of fused silica. ► In the laser etching process window from 0.5 to 2.5 J/cm2 the etching depth is linearly to the laser fluence.