Phonon dynamics of a bulk WSe${}_2$ crystal excited by ultrashort near-infrared pulses

Pump-probe reflectivity measurements have been performed on a single crystal of tungsten diselenide (WSe${}_2$) using ultrashort near-infrared pulses. The behavior is well reproduced in simulations superimposing three oscillations (7.45, 7.49 and 7.7 THz) with different phases. The Fourier transform spectrum features small peaks at 4.0 and 11.5 THz along with intense peaks at around 7.5 THz.