Wave Packets and Dispersion

This lecture covers the concept of wave packets in optics, including Gaussian impulse, Fourier transform, and the uncertainty principle. It also delves into the dispersion of wave packets, group speed, and frequency modulation. The instructor explains how wave packets evolve in space and time, the impact of dispersion on pulse width, and the phenomenon of fast light. The lecture explores the relationship between phase speed and group speed, abnormal dispersion leading to superluminal group speed, and experimental measurements of group index. Additionally, it discusses theoretical aspects such as Kramers-Kronig relations, causality, and the transmission of information faster than light.