High frequency acoustic attenuation in glasses probed with EUV non linear technique
Abstract
The frequency-dependence of the acoustic attenuation in structural glasses holds important information to explain and understand the temperature dependence of the specific heat and thermal conductivity of these materials. However, no technique is able to cover a decade in frequency around ~100GHz, crucial to understand the universal thermal response of glasses in the ~10K temperature range. Thanks to the development of Free Electron Lasers (FEL) and the possibility to implement non linear techniques at wavelengths of few nanometers, we will contribute to fill this experimental gap probing the acoustic excitations of a prototype structural glass (SiO2) stimulated by a transient grating of two coherent EUV FEL pulses. This experiment will be performed at Fermi@Elettra next year and, if successful, will contribute to solve a lively debated scientific problem.