Towards Ultra-Fast Femtosecond-Laser-Assisted Chemical Etching of Mid-IR Transmitting Barium Germano-Gallate (BGG) Glass

The development of very-high-intensity femtosecond laser pulses in the 1980s has led to significant advancements in the field of laser micro/nanostructuring of materials [1]. The Direct Laser Writing (DLW) process, which involves creating 3D structures by focusing a laser beam within transparent materials, stands apart from UV photolithography due to its ability to shape complex three-dimensional geometries. However, the high surface roughness associated with this process prevents the achievement of optical-quality inscriptions.