Impacts of hydroxyl and bond energy on laser-induced damage in mid-infrared chalcogenide glass

Mid-infrared chalcogenide glasses often suffer from a low laser damage threshold due to their weak bond energy and the presence of impurities, particularly at the specific wavelength of 2.94 mu m, which is widely used in medical applications. In this paper, we first investigated the effect of the hydroxyl (OH-) peak absorption coefficient on the laser damage properties of As2S3 glasses. The surface temperature distribution of chalcogenide glasses under laser irradiation was also analyzed using the finite element method (FEM) and in-situ heat monitoring. The results showed that the surface temperature of the glass increases exponentially with the rise in the absorption coefficient at the OH- peak position. Subsequently, Raman spectra analysis and average bond energy (ABE) theory were employed to compare five typical chalcogenide glasses without hydroxyl absorption, revealing the relationship between the laser damage threshold and the bond energies of the glass networks. Finally, an optimized glass composition of Ge25As10S65 was identified, possessing the highest laser damage threshold of 340.98 J/cm2, more than twice that of traditional As2S3. These findings provide essential glass host and data references for the future development of mid- and far-infrared optical fibers and waveguide devices.