Fizeau drag in graphene plasmonics

Area of Science:

• Condensed matter physics
• Quantum optics
• Materials science

Background:

• The Fizeau effect describes light dragging by moving media, a cornerstone of special relativity.
• Experiments dragging photons by electron flow in solids have yielded inconsistent results.
• Surface plasmon polaritons (SPPs) are hybrid quasiparticles of photons and electrons.

Purpose of the Study:

• To investigate the dragging of SPPs by electron flow in graphene.
• To explore the underlying physics of this interaction and its relation to relativistic effects.
• To demonstrate a novel method for breaking time-reversal symmetry in infrared optics.

Main Methods:

• Direct visualization of SPP propagation using infrared nano-imaging.
• Generation and manipulation of high-density currents in graphene.
• Analysis of SPP wavelength changes in response to carrier drift.

Main Results:

• Observed direct dragging of SPPs by electron flow in graphene.
• Demonstrated that SPPs shorten their wavelength when propagating against drifting carriers.
• Showcased that this plasmonic Fizeau drag is governed by nonlinear electrodynamics of Dirac electrons.

Conclusions:

• The electron-induced drag of SPPs in graphene defies simple kinematic explanations.
• This effect enables breaking of time-reversal symmetry and reciprocity at infrared frequencies without magnetic fields.
• The plasmonic Fizeau drag serves as a tool to study electron liquid interactions and nonequilibrium phenomena.