* Title: Ultrafast time-resolved spectroscopy in topological materials
* Speaker: 최현용 (서울대학교 물리천문학부)
* Date: 4pm, 31th March
In this seminar, I will talk about how the extremely fast light, called “ultrafast” laser, is used to investigate the time-resolved phenomena in topological quantum materials. The key players are all optical spectroscopy, optical Stark (Floquet) spectroscopy, and terahertz (THz) spectroscopy. Followed by an introduction about the ultrafast spectroscopy, focus will be made on the following topics. (i) Non-excitonic valley Hall effect in a heterostructure consisted of a monolayer TMD and 2D topological insulator. (ii) Optical Stark effect in a gate-tunable WSe2 device, where we investigate the repulsive and attractive exiton-polarons. (iii) Finally, if time is permitted, I will introduce our THz-pump and THz-probe investigations on the transient dynamics of 3D topological insulators.