Ultrafast optical spectroscopy in the linear-response regime is a crucial technique for studying electronic excitations and charge dynamics in quantum materials. Combining this spectroscopy with extreme external conditions—such as pressure—allows for the investigation of charge dynamics and the formation of energy gaps in pressurized superconductors. In the regime of strong perturbation, intense photoexcitation can generate a sufficient population of excited electrons or drive collective modes to large amplitudes, leading the system into metastable or long-lived states that do not have equilibrium counterparts. This talk will first review ultrafast optical techniques, followed by a focused discussion of our recent work: the detection of the superconducting gap using pump-probe spectroscopy under pressure, and the demonstration of light-controlled functionality in low-dimensional materials.
Bio:
Dr. Tao Dong earned his Ph.D. in Condensed Matter Physics from the Institute of Physics, Chinese Academy of Sciences, in 2014. He currently serves as a Research Associate Professor at the International Center for Quantum Materials, School of Physics, Peking University. His research focuses on developing and applying advanced optical techniques—ranging from the terahertz to the visible spectrum—to investigate and control the properties of materials with strong electron correlations and novel quasiparticle excitations. To date, he has authored over 70 publications, including Physical Review Letters/X (2), Nature Communications (1), Science Advances (2), and one invited review article.
