2D THz spectroscopy on phonons in molecular crystals and semiconductor nanostructures
Date | Mo, 01.07.2019 | |
Time | 16:45h | |
Speaker | Dr. Michael Woerner (Max-Born-Institut, Berlin, Germany) | |
Location | ETHZ, Hönggerberg Campus, HPF G-6 | |
Program | Abstract: Spectroscopy in the terahertz (THz) frequency range (i.e. frequencies between 100 GHz and 30 THz) has developed into an important experimental tool of science and technology. Currently, there are applications in materials science, imaging, sensor technologies, and telecommunications. In recent years there was a huge progress in THz generation providing, nowadays, ultrashort THz pulses with electric field amplitudes of up to several megavolts per centimeter. The new research field of nonlinear THz spectroscopy is a consequence of that development which exploits strong light-matter interactions to induce quantum excitations and/or charge transport and to follow their nonequilibrium dynamics in time-resolved experiments[1]. Among such spectroscopies is the so-called two-dimensional (2D) THz spectroscopy with a fully phase-resolved detection of the nonlinearly emitted electric field transients. Such an experimental tool gives new insights into elementary excitations of condensed matter, among them, phonons in molecular crystals [2] and semiconductor nanostructures[3]. In this talkI will introduce the method of nonlinear THz spectroscopy in a tutorial wayand present prototypical, experimental results in condensed matter physics. The potential of nonlinear THz spectroscopy is illustrated by recent research[2,3]. [1] T. Elsaesser, K. Reimann, M. Woerner: Concepts and applicatons of nonlinear terahertz spectroscopy, Morgan & Claypool Publishers, San Rafael (2019) [2] G. Folpini, K. Reimann, M. Woerner, T. Elsaesser, J. Hoja, A. Tkatchenko:Strong local-field enhancement of the nonlinear soft-mode response in a molecular crystal, Phys.Rev.Lett.119, 097404(2017). [3] M. Woerner, C. Somma, K. Reimann, T. Elsaesser, P. Q. Liu, Y. Yang, J. L. Reno, I. Brener: Terahertz driven amplification of coherent optical phonons in GaAs coupled to a metasurface, Phys.Rev.Lett.122, 107402 (2019) . |
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Link | Laser Seminars |