Abstract-Using ultrashort terahertz pulses to directly probe spin dynamics in insulating antiferromagnets

Pamela Bowlan, S A Trugman, Dzmitry Yarotski, Antoinette J Taylor, Rohit P Prasankuma

http://iopscience.iop.org/article/10.1088/1361-6463/aab8da

Terahertz pulses are a direct and general probe of ultrafast spin dynamics in insulating antiferromagnets (AFM). This is shown by using optical-pump, THz-probe spectroscopy to directly track AFM spin dynamics in the hexagonal multiferroic HoMnO3 and the orthorhombic multiferroic TbMnO3. Our studies show that despite the different structural and spin orders in these materials, THz pulses can unambiguously resolve spin dynamics after optical photoexcitation. We believe that this approach is quite general and can be applied to a broad range of materials with different AFM spin alignments, providing a novel non-contact approach for probing AFM order with femtosecond temporal resolution.

Abstract-Ultrafast two-dimensional terahertz spectroscopy of elementary excitations in solids

Michael Woerner, Wilhelm Kuehn, Pamela Bowlan, Klaus Reimann and Thomas Elsaesser
http://iopscience.iop.org/1367-2630/15/2/025039

Recent experimental progress has allowed for the implementation of nonlinear two-dimensional (2D) terahertz (THz) spectroscopy in the ultrafast time domain. We discuss the principles of this technique based on multiple phase-locked electric field transients interacting in a collinear geometry with a solid and the phase-resolved detection of the THz fields after interaction with the sample. To illustrate the potential of this new method, 2D correlation spectra of coupled intersubband-longitudinal optical phonon excitations in a double quantum well system and a study of ultrafast carrier dynamics in graphene are presented.