Revealing the frequency-dependent oscillations in the nonlinear terahertz response induced by the Josephson current

Abstract

Nonlinear responses of superconductors to intense terahertz radiation has been an active research frontier. Using terahertz pump-terahertz probe spectroscopy, we investigate the c-axis nonlinear optical response of a high-temperature superconducting cuprate. After excitation by a single-cycle terahertz pump pulse, the reflectivity of the probe pulse oscillates as the pump-probe delay is varied. Interestingly, the oscillatory central frequency scales linearly with the probe frequency, a fact widely overlooked in pump-probe experiments. By theoretically solving the nonlinear optical reflection problem on the interface, we show that our observation is well explained by the Josephson-type third-order nonlinear electrodynamics, together with the emission coefficient from inside the material into free space. The latter results in a strong enhancement of the emitted signal whose physical frequency is around the Josephson plasma edge. Our result offers a benchmark for and new insights into strong-field terahertz spectroscopy of related quantum materials.

8 pages, 4 figures

References in corpus (9)

• Terahertz-Field-Induced Ferroelectricity in Quantum Paraelectric SrTiO${}_3$
• The Ground State of the Pseudogap in Cuprate Superconductors
• Band-selective third-harmonic generation in superconducting MgB${}_2$: Possible evidence for Higgs amplitude mode in the dirty limit
• Near-infrared light-induced superconducting-like state in underdoped YBa${}_2$Cu${}_3$O${}_y$ studied by $c$-axis terahertz third-harmonic generation
• Periodic dynamics in superconductors induced by an impulsive optical quench
• Fano interference of the Higgs mode in cuprate high-Tc superconductors
• Transient Higgs oscillations and high-order nonlinear light-Higgs coupling in terahertz-wave drivenNbN superconductor
• Terahertz third harmonic generation in c-axis La${}_{1.85}$Sr${}_{0.15}$CuO${}_4$
• Tunable near- to mid-infrared pump terahertz probe spectroscopy in reflection geometry

Cited by in corpus (9)

• Revealing novel aspects of light-matter coupling in terahertz two-dimensional coherent spectroscopy: the case of the amplitude mode in superconductors
• Probing Inhomogeneous Cuprate Superconductivity by Terahertz Josephson Echo Spectroscopy
• Principles of 2D terahertz spectroscopy of collective excitations: the case of Josephson plasmons in layered superconductors
• Investigating Josephson plasmons in layered cuprates via nonlinear terahertz spectroscopy
• Photon echo and fractional excitation lensing of $S=1/2$ XY spin chain
• Discovery of an Unconventional Quantum Echo by Interference of Higgs Coherence
• Multidimensional coherent spectroscopy of correlated lattice systems
• Two-dimensional THz spectroscopy in electronic systems: a many-body diagrammatic approach
• Dynamical signatures and control of time-reversal breaking in twisted nodal superconductors