Femtosecond laser etching of Li1.5Al0.5Ge1.5(PO4)3 glass using the Bessel beam

Surface textured materials can exhibit enhanced properties due to their unique morphology, large surface area, and modified surface properties. The laser etching process has garnered significant attention for its capability to create textures on sample surfaces, resulting in a substantial improvement of surface properties. In this study, we investigate the application of femtosecond laser etching on solid electrolytes. To achieve this, an axicon lens is employed to transform the conventional Gaussian beam into a Bessel beam, with an extended focal depth that facilitates the laser etching process. A telescope laser system with a Bessel beam having a focal length of 2 mm is constructed based on finite element analysis. Glassy LAGP [Li1.5Al0.5Ge1.5(PO4)3] with a thickness of 2 mm is successfully etched simultaneously on both surfaces using this approach. Utilization of femtosecond laser pulses effectively prevents sample melting during the process. As predicted by finite element analysis, wider ditches are observed on the surface compared to those on the backside due to higher laser intensity at the surface region. By modifying the parameters of the telescope laser system, size and depth control can be achieved for these ditches.