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arXiv · 2112.12123

Quench-drive spectroscopy and high-harmonic generation in BCS superconductors

Matteo Puviani·Rafael Haenel·Dirk Manske
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Abstract

In pump-probe spectroscopies, THz pulses are used to quench a system, which is subsequently probed by either a THz or optical pulse. In contrast, third-harmonic generation experiments employ a single multicycle driving pulse and measure the induced third harmonic. In this work, we analyze a spectroscopy setup where both a quench and a drive are applied and two-dimensional spectra as a function of time and quench-drive delay are recorded. We calculate the time evolution of the nonlinear current generated in the superconductor within an Anderson-pseudospin framework and characterize all experimental signatures using a quasiequilibrium approach. We analyze the superconducting response in Fourier space with respect to both the frequencies corresponding to the real time and the quench-drive delay time. In particular, we show the presence of a transient modulation of higher harmonics, induced by a wave mixing process of the drive with the quench pulse, which probes both quasiparticle and collective excitations of the superconducting condensate.

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Matteo Puviani, Rafael Haenel, Dirk Manske. 2021-12-22. Quench-drive spectroscopy and high-harmonic generation in BCS superconductors. https://doi.org/10.1103/physrevb.107.094501

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