Raman gain in tellurite glass: how combination of IR, Raman, Hyper-Raman and Hyper-Rayleigh brings new understandings
Résumé
A new multimodal approach that combines linear and nonlinear vibrational spectroscopies and hyper-Rayleigh scattering has been applied in the TeO2–TaO5/2–ZnO glass system to assess and quantify the relation between Raman gain and optical responses within the glass’ network arrangement. The level of polymerization of the TeO4 chain-like structure in a TeO2 glass system has been identified to be the main parameter for reaching high linear and nonlinear optical constant. We have observed that replacement of TaO5/2 by ZnO strongly modifies the optical properties and, primarily, the Raman and hyper-Raman spectra of the glasses. In particular, we clearly demonstrate a linear relationship between Raman gain and the linear and second-order optical response of the glass, which is directly related to the number density of TeO4 chain-like units. Assuming that only TeO4 chain-like units contribute significantly to the glass’ polarizability, we have found that about 30% of the Te atoms contribute to the hyperpolarizability of the binary system 80TeO2–20ZnO in very good accordance with neutron diffraction results.