Carlo Vicario (SIMES Seminar)

Date/Time
Date(s) - Feb 16 2016
10:00 AM - 11:00 AM

Location
Sycamore Room, Building 40, room 195

Category(ies)


Strong-terahertz field effects in ferromagnet and semiconductors

Carlo Vicario
Paul Scherrer Institute, SwissFEL, Villigen-PSI, Switzerland
Email: carlo.vicario@psi.ch

Recent developments in high field terahertz open new perspective for controlling optical, electronic and magnetic properties of matter on a sub-cycle timescale. In this talk I will present the high-power Terahertz source developments pursued at the Paul Scherrer Institute and discuss a scheme for confining the THz energy in diffraction-limited spot size and single-oscillation (socalled lambda-cubic volume) [1]. I will discuss furthermore, THz strong-field dynamics observed in semiconductors and magnetic thin films. Electric and magnetic fields reaching tens of MV/cm and several Tesla are used to manipulate ultrafast coherent spin dynamics and to change the optical properties of transparent materials on a sub-cycle timescale. As examples, I will present octavespanning spectral broadening by cross-phase-modulation and coherent magnetic dynamics [2]. Furthermore I will introduce 2-dimensional THz detectors based on CCD technology, which provides significantly higher spatial resolution, larger chip area and faster readout compared to the conventional THz imagers [3].

abstract2

Fig. Large broadening of a laser spectrum triggered by strong THz field. The 2D map reports the laser abstractspectra (horizontal axis) at different delays with respect to the THz transient (vertical coordinates).

Reference:
1. M. Shalaby, C. Vicario, C.P. Hauri, Nature Commun. doi: 10.1038/ncomms9439 (2015)
2. C.Vicario et al, Nature Photon. (2013) doi: 10.1038/NPHOTON.2013.209 (2013)
3. M. Shalaby, C.P. Hauri, Nature Commun. 6:5976 doi: 10.1038/ncomms6976 (2015)