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arXiv · 2203.03656

Terahertz displacive excitation of a coherent Raman-active phonon in V$_2$O$_3$

Flavio Giorgianni·Mattia Udina·Tommaso Cea·Eugenio Paris·Marco Caputo·Milan Radovic·Larissa Boie·Joe Sakai·Christof W. Schneider·Steven Lee Johnson
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Abstract

Nonlinear processes involving frequency-mixing of light fields set the basis for ultrafast coherent spectroscopy of collective modes in solids. In certain semimetals and semiconductors, generation of coherent phonon modes can occur by a displacive force on the lattice at the difference-frequency mixing of a laser pulse excitation on the electronic system. Here, as a low-frequency counterpart of this process, we demonstrate that coherent phonon excitations can be induced by the sum-frequency components of an intense terahertz light field, coupled to intraband electronic transitions. This nonlinear process leads to charge-coupled coherent dynamics of Raman-active phonon modes in the strongly correlated metal V$_2$O$_3$. Our results show a new up-conversion pathway for the optical control of Raman-active modes in solids mediated by terahertz-driven electronic excitation.

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Flavio Giorgianni, Mattia Udina, Tommaso Cea, Eugenio Paris, Marco Caputo, Milan Radovic, Larissa Boie, Joe Sakai, Christof W. Schneider, Steven Lee Johnson. 2022-03-07. Terahertz displacive excitation of a coherent Raman-active phonon in V$_2$O$_3$. https://arxiv.org/abs/2203.03656

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