Slicing of large-size single crystals by ultrafast laser with external stress assistance

The existing single-crystal slicing techniques result in significant material wastage and elevate the production cost o premium-quality thin slices of crystals.Here we report(for the first time,to our knowledge)an approach for vertical slicin of large-size single-crystal gain materials by ultrafast laser.By employing aberration correction techniques,the optimi zation of the optical field distribution within the high-refractive-index crystal enables the achievement of a continuou laser-modified layer with a thickness of less than 10μm,oriented perpendicular to the direction of the laser direction The compressed focal spot facilitates crack initiation,enabling propagation under external forces,ultimately achievin the successful slicing of aΦ12 mm crystal.The surface roughness of the sliced Yb:YAG is less than 2.5μm.The result illustrate the potential of low-loss slicing strategy for single-crystal fabrication and pave the way for the future develop ment of thin disk lasers.