Figure 4: Photo-excited coherent lattice dynamics for T > Ts.
From: Direct characterization of photoinduced lattice dynamics in BaFe2As2
(a) Temporal evolution of the line cut after subtraction of the averaged line cuts before time zero. (b) Integrated intensity on the area detector as a function of time. Both a and b show a distinct modulation of the (118)T Bragg peak intensity after photoexcitation. Time zero (Δt=0) is defined as the time delay, at which one observes a rise of the diffracted Bragg peak intensity. The background (black line) is modelled as a convolution of the overall time resolution and an exponential decay of the initial ultrafast intensity rise, on a linear slope. (c) The background-subtracted integrated intensity and the Fourier transform (FT, inset of b) both identify the coherent oscillations with the 5.45(4) THz A1g phonon mode. The frequency error from a damped oscillator fit to the background-subtracted integrated intensity δI(Δt)/I0 (red line in c) corresponds to 1 s.d.
