Stimulated Scattering and Brillouin-Raman Interactions

This lecture covers stimulated scattering in dense media, where molecules vibrate collectively, leading to classical and optical-like vibrations. It explores Raman scattering in silica molecules, discussing energy transfer, vibration frequencies, and gain. The lecture also delves into Brillouin scattering, describing the interaction between pump and Stokes beams through acoustic waves, resulting in backscattered light. The Brillouin threshold and its relation to pump power, gain coefficient, and bandwidth are explained. Additionally, the lecture addresses the limitations of stimulated Brillouin scattering in fiber systems, emphasizing the impact of acoustic velocity on phase matching conditions and the potential applications in distributed sensors for temperature and strain.