Giant ultrafast Kerr effect in superconductors

Abstract

We study the ultrafast Kerr effect and high-harmonic generation in type-II superconductors by formulating a new model for a time-varying electromagnetic pulse normally incident on a thin-film superconductor. It is found that type-II superconductors exhibit exceptionally large χ (3) due to the progressive destruction of Cooper pairs, and display high-harmonic generation at low incident intensities, and the highest nonlinear susceptibility of all known materials in the THz regime. Our theory opens up new avenues for accessible analytical and numerical studies of the ultrafast dynamics of superconductors.

Polarization dependence of the third-harmonic generation in multiband superconductors

“…This identification justifies the subscripts in Eq. (9a)- (12). The quadratic terms in ∆ a , θ a and ρ define the spectrum of the collective modes, see Eq.…”

Giant asymmetric self-phase modulation in superconductor thin films

“…As seen in Fig. 2, the sech-shaped pulse (maintain-ing its shape throughout propagation) causes the order parameter to dip and then recover as it interacts with the superconductor (this has been studied in more depth in our previous work [17]) whilst its spectrum redshifts substantially, producing lateral lobes. The supergaussian pulse simulation result shown in Fig.…”

“…Here we present the results from our numerical solutions of equations (6) and (7) in the THz regime, which is of interest in applications [15,16]. However, nothing prevents the application of our model to different frequency ranges, for instance in the near-IR or the visible, although in these regions the nonlinearity drops sharply, since it depends on a factor ω 6 , while in the THz regime the nonlinear susceptibility of superconductors is the largest for all known materials [17].…”

Time-dependent Ginzburg-Landau treatment of rf magnetic vortices in superconductors: Vortex semiloops in a spatially nonuniform magnetic field

“…We note that TDGL was previously used to study vortex dynamics and V-I characteristics of 2-D rectangular thin films [58], vortex entry in the presence of twin boundaries [7] and the vortex dynamics under ac magnetic field in mesoscopic superconductors [59]. More recently, the TDGL formalism was used to estimate the strength of the Kerr effect in a superconductor when a short light pulse is applied [60].…”

“…where χ( r, t) is any (sufficiently smooth) real-valued scalar function of position and time. One can fix the gauge as ∂χ( r, t) ∂t = e * h Φ( r, t) in order to effectively eliminate the electric potential at all times [60,62]. It is useful to introduce dimensionless variables (denoted by twiddles ∼) to simplify the simulation and normalize Eqs.…”