Fig. 4: Simultaneous excitation of multiple degrees of freedom in LSMO.
From: Multi-mode excitation drives disorder during the ultrafast melting of a C4-symmetry-broken phase
a Fluence dependence of the order parameter and the amplitude of the 2.7 THz mode from r. The order parameter shows a monotonic decrease whereas the phonon amplitude first rises before being suppression at the same fluences as the order parameter. b Focused and normalized view of the first 500 fs of ƞ2 showing a marked speedup with increasing fluence. c Same as b but for r. In contrast to ƞ2 a slowdown is observed with increasing fluence. d Few-cycle pump-probe measurements of phonon dynamics with 1800 pump and 650 nm probe pulses (see methods and Supplementary Fig. S5 for details). 2.7, 6, 16 and 19 THz modes of LSMO are clearly observed and in good agreement with the literature33 (dashed lines). The 2.7 and 6 THz modes are suppressed as the system is pumped through the transition, while the high-frequency modes broaden.
