Micron-precision in cleaving glass using ultrafast Hessel beams with engineered transverse beam shapes

Ultrafast lasers in association to beam shaping have shown to be excellent candidates for transparent material processing. Non-diffractive solutions such as Bessel beams allows for precise energy deposition since they are robust to undesired non-linear effects and as they do not distort along the propagation. This offers important opportunities in laser-assisted cleaving, i.e. mechanical medium separation after single-pass laser illumination. Here we break the Bessel beam cylindrical symmetry using a novel anisotropic and non-diffractive solutions to investigate both lateral intensity contributions on material response and induced processing effect for non-cylindrical defects. Using such beam shape, we report a strong cleavability enhancement as well as an improvement of the final robustness of the separated glass in comparison with Bessel beams. We demonstrate cleaving for laser-writing speed as high as 25mm/s with ~1μm accuracy over the whole 20mm sample length.