Non-linear Raman effects and photodarkening in chalcogenide glass As2S3

摘要

The intensities of Raman-scattering bands in the spectrum of vitreous As2S3 assigned to vibrations of intrinsic homopolar As-As (similar to 234 cm(-1)) and S-S (similar to 490 cm(-1)) bonds increase much more with the power of the exciting laser than does the principle vibrational band which is related to As-S-As glass-network vibrations (similar to 343 cm(-1)). In addition, the frequency of this glass-network vibration softens with an increase of the laser power. We ascribe these non-linear Raman effects to a photo-stimulated increase in polarizability of the homopolar bonds accompanied by softening of glass-network vibrations. It is suggested that this non-linearity is related to photodarkening in As2S3.