Water-assisted laser drilling of high-aspect-ratio 3D microchannels in glass with spatiotemporally focused femtosecond laser pulses

We report fabrication of three-dimensional (3D) high aspect ratio microchannels from the rear-surface of thick silica glass with femtosecond laser pulses. To avoid nonlinear self-focusing in the conventional focusing scheme which leads to intensity clamping in the interaction of the ultrafast laser pulses with the silica glass, simultaneous spatiotemporal focusing is employed which gives rise to high aspect ratio (~30) straight and curved microchannels in 10mm thick silica glass substrates.