Phase-resolved Higgs-Spectroscopy in Superconducting Cuprates using non-linear THz spectroscopies*

High field THz-pulses allow accessing the Higgs mode, the amplitude mode of the order parameter, in superconductors. Using a phase-resolved THz-high-harmonics-spectroscopy allows performing a complex Higgs-spectroscopy of the order parameter dynamics, symmetry and interaction with other collective modes [1,2]. In high-Tc cuprates and NbSe2 this allows investigating the interplay of charge density waves (fluctuations) and superconductivity based on a generalised Fano-interference of the driven order parameters [1,3,4]. As time-resolved technique THz-Higgs spectroscopy also allows probing transient superconducting states driven by ultrashort light pulses [5,6]. In these the phase sensitive measurement technique allows applying a 2D THz-third harmonics spectroscopy to disentangle different sources of third harmonics generation and describe their interplay [6]. A novel and direct view on Higgs can be opened by non-equilibrium Raman spectroscopy in the anti-Stokes channel [7].

[1] H. Chu et al. Nat. Commun. 11, 1793 (2020)

[2] L. Schwarz et al. Nat Commun. 11, 287 (2020)

[3] H. Chu et al. Nat Commun. 14, 1343 (2023)

[4] L. Feng et al. PRB 108, L100504 (2023)

[5] K. Katsumi et al. PRB 107, 214506 (2023)

[6] M. Kim et al. arxiv:2303.03288

[7] T. Glier et al. arxiv:2310.08162