Nonlocal and nonlinear effects on the dispersion relation for surface plasmon at ametal–Kerr medium interface

Abstract

We present a theoretical study on the dispersion relation for surface plasmons at ametal–Kerr medium interface where the metal is described by a nonlocal dielectric functionaccording to the hydrodynamic model. The Kerr effect leads to a shift of the surfaceplasmon frequency depending on the electric field intensity, the magnitude aswell as the sign of the Kerr coefficient, and the wavevector. We further observethat this frequency shift is largely quenched for large wavenumbers for whichthe nonlocal effect is significantly manifested. We account for this quenchingquantitatively by a calculation showing how the nonlocality weakens the sensitivityin the metal’s response to the variation of the dielectric function of the Kerrmedium. A possible experimental observation of this new effect is briefly discussed.