NCTS (South)



PLACER49223, Second Physics Building , NCKU

FIELDQuantum Information Science

SPEAKER Prof. Yu-Miin Sheu(許鈺敏) - 交通大學電子物理系

TITLEUltrafast Optical Science and Its Application for Condensed Matters

ABSTRACTHow do one measure electrons during their scattering? Can you take a picture during spins’ precession? Do you know that you can kick a lattice by force provided by optical pulses, launching lattice vibration (phonon) that you can watch it in real time? The motion of electrons, spins, and phonon is so fast in condensed matters, i.e. on the time scale of femtoseconds to picoseconds. They play different roles governing the important physical properties such as superconducting, insulating, various magnetic properties and so on. The motion is too fast to be observed through the slow detector response; therefore, traditional methods measure these properties in the frequency domain. With the development of ultrafast optical techniques, the observation of fast motion becomes feasible. Not only it can detect fast dynamics, the property of ultrashort and intense laser pulses can also allow various nonlinear processes, extending the probe methods that may be sensitive to various order parameters in condensed matters. During this seminar, I will introduce the ultrafast science to discuss the background of ultrafast lasers and pump-probe techniques. Then I will discuss various cases in condensed matters in which the technique is particularly useful. Furthermore, as the intense pulse can cause highly nonequilibrium states, hidden states not achievable through thermodynamic process could possibly be induced and discovered through the application of such techniques. Finally, I will summarize its general capability applied for condensed matter physics.