Fracture toughness of ultrashort pulse-bonded fused silica

We determined the bond interface strength of ultrashort pulse laser-welded fused silica for different processing parameters. To this end, we used a high repetition rate ultrashort pulse laser system to inscribe parallel welding lines with a specific V-shaped design into optically contacted fused silica samples. Afterward, we applied a micro-chevron test to measure the fracture toughness and surface energy of the laser-inscribed welding seams. We analyzed the influence of different processing parameters such as laser repetition rate and line separation on the fracture toughness and fracture surface energy. Welding the entire surface a fracture toughness of 0.71 MPa m 1 / 2 , about 90 % of the pristine bulk material ( ≈ 0.8 MPa m 1 / 2 ) , is obtained.