All-optical amplification in metallic subwavelength linear waveguides

摘要

The proposed all-optical amplification scenario is based on the properties of light propagation in two coupled subwavelength metallic slab waveguides where, for a particular choice of waveguide parameters, two eigenmodes coexist: propagating (symmetric) and nonpropagating (antisymmetric). For such a setup incident beams realize boundary conditions for forming a stationary state as a superposition of the mentioned eigenmodes. It is shown both analytically and numerically that the amplification rate in this completely linear mechanism diverges for small signal values.