LAUSR

The study of the dynamics of the interaction of intense electromagnetic fields with metallic nanoparticles is a great interest of some applied nonlinear phenomena in nano-optics and plasmonics. These phenomena include harmonics generation, nano-focusing, self-focusing, nonlinear modes and nano-waveguiding. Using a relativistic modified Drude model, we analytically solve the motion equations of conduction electrons of spherical nanoparticles in a linear chain interacting with a linearly-polarized laser propagating perpendicular to the symmetry axis of the chain. The mutual interaction of each particle with two adjacent neighbors has been considered in the dipole-dipole interaction regime. By means of a perturbative approach, the motion equations related to the first, second and third harmonics of electromagnetic fields are solved. Numerical studies are carried out for a linear chain including 10 of 10 nm radius gold nanoparticles. The effect of interparticle separation and laser polarization on the nonlinear dynamics of the system has been investigated. It is shown that the interaction of particles causes a blueshift for the plasmon resonance of the system for the polarization of laser where the electric field is perpendicular to the symmetry axis of the chain. In the parallel case of the laser electric field, plasmon resonance frequency experiences a redshift for the first and third harmonics displacements, whereas it blueshifts for the second harmonics due to the interparticle interactions. Also, the interaction of particles causes a decrease in the amplitude of the conduction electrons at the plasmon resonance region for the perpendicular state of laser polarization and its increase for the parallel state.