Second-harmonic generation in metal nanoparticles modeling by surface integral equation

Metals are centrosymmetric materials which only posse local surface second-harmonic (SH) nonlinearities due to the symmetry broken at the surface. In this work the surface integral equation (SIE) is used for evaluating SH radiation generated from metal nanoparticles with arbitrary shapes. The whole SIE system is solved by employing the Galerkin testing procedure and Rao-Wilton-Gillson (RWG) basis functions. The mutual coupling between fundamental and second harmonic field is captured. The method is validated by comparisons with the analytic SH-Mie solution. This method paves the way for accurate and efficient design of general SH nonlinear nanoplasmonic structures.