Nano‐Cracks and Glass Carving from Non‐Symmetrically Converging Shocks

Abstract

A method is presented to carve into a glass submerged in water with laser‐induced surface and shock waves. It starts with an elliptic wave source that launches an elliptically converging Rayleigh and shock wave. At the wave focus a single microscopic crack with controlled location and orientation is induced that has a length of a few micrometers and a width of about 100 nm. Through successive surface waves, this crack may be extended along a specific direction which can be controlled by adjusting the distance, shape, and orientation of the laser focus. Here, either point‐like or elliptical laser foci are generated using a spatial light modulator. Furthermore, when the crack is guided along a closed circular path using a point like laser focus, a conchoidal hole may be carved through the glass slide demonstrated with a 160 µm thick cover slip. The shock waves are modeled in the fluid and the elastic waves in the glass in three dimensions with a finite‐volume framework that accounts for fluid‐structure interaction. The resulting pressures and stresses for both the elliptical and point‐like Rayleigh and shock wave sources are reported.