Fig. 1: Transient reflectivity spectroscopy.
From: Terahertz signatures of ultrafast Dirac fermion relaxation at the surface of topological insulators
THz-pump optical-probe (TPOP) reflectivity measurements in Bi2Se3 (a), Bi2Te3 (b) and BSTS (c) (blue line). The intensity transient of the driving THz field is shown in all panels (gray shaded line). The red line corresponds to the dynamics when using optical excitation with 1.5 eV photon energy (OPOP). The band diagram with the Fermi level of each sample, obtained from THz transmission experiments, is schematically shown in the insets.
