Work

Theory of relativistic surface plasmon excitation on smooth surfaces by high-intensity lasers

Year: 2026

Type: article

Abstract: We present a classical theory of relativistic surface plasmon (RSP) excitation at smooth planar and cylindrical plasma-vacuum interfaces driven along the surface or channel axis by the ponderomotive force or carrier electric field of an intense laser pulse. Starting from Maxwell’s equations and a cold-fluid plasma response, we derive a general driven-mode equation and obtain analytical solutions for Gaussian sources. Excitation is governed by the overlap between the drive and the surface eigenfield, together with frequency and wavenumber matching. An infinite planar interface conserves in-plane momentum, while cylindrical geometry replaces one continuous tangential wavenumber with a discrete azimuthal index and retains axial phase-matching requirements. Within a frozen-quiver relativistic Drude model, the field shows saturation on planar surface, whereas cylindrical curvature mitigate this effect by modifies the mode dispersion and the field confinement. Preliminary particle-in-cell simulations show qualitative agreement with the predicted intensity dependence. Cylindrical symmetry also imposes source-dependent azimuthal selection rules, and the axisymmetric mode supports a nonzero on-axis accelerating field. These results clarify how surface geometry controls RSP excitation and provide a framework that can be extended to other geometries and driving mechanisms.

Source: New Journal of Physics

DOI: 10.1088/1367-2630/aeb821

Authors: Bifeng Lei, Bin Qiao, Matt Zepf, Guoxing Xia, Carsten Welsch