Polarization properties of quasielastic light scattering in fused-silica optical fiber

Polarized and depolarized components of the quasielastic light-scattering spectrum of fused-silica optical fiber have been measured in the frequency range 100 kHz to 100 MHz at temperatures from 10 to 293 K. The depolarization ratio was found to be 0.140.03. In the backscattering geometry both polarization components are seen to obey an inverse-power-law frequency dependence. Both the temperature and frequency dependence are consistent with a model that assumes thermal activation of structural relaxations which have a wide distribution of relaxation-time constants. In the forward direction, an additional polarized component with the same temperature dependence appeared. © 1990 The American Physical Society.