Ultrafast optical pump - optical probe and optical pump - terahertz probespectroscopy were performed on vanadium dioxide (VO2) and vanadium sesquioxide(V2O3) thin films over a wide temperature range. A comparison of theexperimental data from these two different techniques and two differentvanadium oxides, in particular a comparison of the electronic oscillationsgenerated by the photoinduced longitudinal acoustic modulation, reveals thestrong electron-phonon coupling that exists in the metallic state of bothmaterials. The low energy Drude response of V2O3 appears more susceptible thanVO2 to ultrafast strain control. Additionally, our results provide ameasurement of the temperature dependence of the sound velocity in bothsystems, revealing a four- to fivefold increase in VO2 and a three- to fivefoldincrease in V2O3 across the phase transition. Our data also confirmobservations of strong damping and phonon anharmonicity in the metallic phaseof VO2, and suggest that a similar phenomenon might be at play in the metallicphase of V2O3. More generally, our simple table-top approach provides relevantand detailed information about dynamical lattice properties of vanadium oxides,opening the way to similar studies in other complex materials.
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