Near-field optical properties of single plasmonic nanowires

The authors apply the finite difference time domain method to study the propagation of a local excitation along metallic nanowires of subwavelength cross section. The metallic nanowires are elongated cylinders deposited on a transparent substrate. A tightly focused Gaussian beam illuminates one end of the nanowires. The localized surface plasmon excitations propagate along the nanowire over distances much larger than the incident wavelength. According to recent experimental studies, they show that such nanostructures behave like a Fabry-Pérot cavity with large value of surface plasmon propagation length.