FBS Colloquia No.410Photophysics Laboratory

Seeing Electron Dynamics with Light — From the Photoelectric Effect to Ultrafast Spectroscopy

Light allows us to perceive materials through their color and brightness when it is incident upon them. This is because the response of electrons to light appears as reflection and absorption. In this colloquium, I will provide an overview of methods to observe electron dynamics using light, covering topics from fundamental principles to state-of-the-art techniques. I will begin with a simple demonstration of the photoelectric effect to offer an intuitive understanding of light–matter interactions.
Based on this principle, I will introduce the basic concept of photoelectron spectroscopy and explain how it can be used to probe the electronic states in solids. I will then extend the discussion to ultrafast spectroscopy using pulsed lasers, which enables the observation of electron dynamics on femtosecond timescales.
Finally, I will present recent studies on electron behavior in nonequilibrium solid-state systems, and discuss potential applications in photo functional materials as well as possible connections to biological systems.