Fig. 4: Time-resolved THz-THG signal under the photoexcitation.
From: Light-induced enhancement of superconductivity in iron-based superconductor FeSe0.5Te0.5
a Waveform of the third harmonic (TH) component of the transmitted probe pulse. A black arrow at t = 3.5 ps indicates the arrival time of the pump pulse to the sample. The pump fluence is 2.6 µJ cm−2. b TH component of the terahertz field measured at fixed pump–probe delay times, tpp, respectively. c Time evolution of the TH intensity, \(I_{{\mathrm{TH}}}\left( {t_{{\mathrm{pp}}}} \right)\), normalized by the TH intensity in equilibrium, \(I_{{\mathrm{TH}}}^{{\mathrm{eq}}}\). Arrows indicate pump–probe delay times at which the THz waveforms shown in b were measured. d Calculated waveform of the TH signal and e time evolution of the TH intensity, which correspond to the experimental results shown in a, c, respectively. Time evolution of the superconducting gap energy after the photoexcitation normalized by the gap energy in equilibrium, \(2{\mathrm{{\Delta}}}\left( {t_{{\mathrm{pp}}}} \right)/2{\mathrm{{\Delta}}}_{{\mathrm{eq}}}\), which is used for the calculation, is shown in the inset.
