Resonant absorption of plasmonic cylinder near boundary between dielectrics

Discrete Dipole Approximation (DDA) is one of the best methods for light scattering calculation. We expand it to solve a 2-dimensional problem in two different semi-spaces. Considering a cylinder parallel to the plane boundary, we derive a special-kind 2-dimensional Green's tensor that intrinsically accounts for the boundary conditions for electromagnetic fields. We numerically calculate the local field as a scattering angle function and compare the dependencies with the previous results obtained by another method. We demonstrate the red shift of the plasmon resonance that is due to the interference of the fields, scattered by the cylinder directly and reflected from the interface. In the case of subwavelength diameter, when a dipole approximates the cylinder, the interface can be replaced by a mirror-image dipole. As shown, the corresponding analytical approximation provides good estimations for main properties of the cylinder's resonance. The method suits well for study a particle on a substrate. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Discrete Dipole Approximation (DDA) is an effective method for light scattering calculation. This paper extends it to solve a 2-dimensional problem in two different semi-spaces and considers the influence of boundary conditions on electromagnetic fields. Through numerical calculations and comparisons, the correlation between the scattering angle function and previous results, as well as the red shift phenomenon of the plasmon resonance, are demonstrated.