Ultrafast and terahertz spectroscopy for visualization of irreversible phenomena - photoinduced phase change and laser ablation –

Ikufumi Katayama, de l'Université de Yokohama donnera un séminaire sur des nouvelles techniques de mesures ultra-rapides par laser, et leurs applications dans les domaines Terahertz et infrarouge

Department of Physics, Yokohama National University, Japan

Ultrafast and terahertz spectroscopy have been important experimental tools to reveal the dynamics at femtosecond timescales. They require, however, the repetition of the measurements to acquire the full temporal waveform, limiting the application of the spectroscopy to the phenomena  that are reversible within a short timescales. Ultrafast dynamics of irreversible phenomena such as the photoinduced phase change and the laser ablation are left unexplored, although they are important for random access memory such as DVD and femtosecond laser manufacturing, respectively. Here, we show that single-shot ultrafast spectroscopy using reflective echelon mirrors and the time-encoding technique can reveal the pulse-to-pulse ultrafast dynamics of these phenomena, which are crucial for understanding the underlying physics.