Correlation among Structure, Water Peak Absorption, and Femtosecond Laser Ablation Properties of Ge-Sb-Se Chalcogenide Glasses

A series of Ge11.5SbxSe88.5-x (x = S, 10, 15, 20, 25, 30) chalcogenide glasses were fabricated aiming at investigating the role of structure and water peak absorption in determining femtosecond laser ablation thresholds (F-th). The results indicate that the optical band gap decreases and that the Vickers hardness increases with increasing Sb content. Meanwhile, Raman spectra were measured before the femtosecond laser ablation experiment, suggesting a rise in average bond energy in the six glass samples with increasing Sb concentration. Ablation of the sample disks in air were performed with high repetition rate ultrashort laser pulses (150 fs, 1 kHz) at different wavelengths (2.86 and 4 mu m) to investigate how the water peak absorption coefficient affects ablation thresholds, which reveals the dominating role of the multiphoton ionization (MPI) progress on the ablation threshold fluence. The results will be useful for photonic devices based on Ge-Sb-Se glasses applied in high-power laser operations to prevent ablation.