Fig. 2: Signature of the driven Higgs oscillations in transient response and polarization dependence.
From: Phase-resolved Higgs response in superconducting cuprates
a THG intensity normalized by the parallel transmitted FH power (ITH/IFH3) for LSCO(OP45) as a function of θ, the angle from the Cu–O bond direction. THG from the Higgs oscillation is expected to be isotropic, while THG from charge density fluctuation (CDF) is expected to be anisotropic. b Transient reflectivity of LSCO(OP45) is measured with an 80 fs optical pulse while it is pumped with the 0.7 THz multicycle terahertz pulse. The change in reflectivity, ΔR, as a function of delay between the pump pulse and the probe pulse is shown in the inset. Main figure shows the FFT power spectrum of the relevant time intervals marked in the inset. ΔR exhibits a 1.4 THz (black dotted line) modulation while the pump pulse is on (red line) due to the |A | 2 coupling of the condensate to the terahertz drive. The 1.4 THz peak becomes indistinguishable after the pump pulse is gone (blue line). c THG polarization dependence for DyBCO(OP90). The error bars represent standard deviation due to pulse-to-pulse intensity fluctuation.
