Subwavelength Surface Plasmon Optical Cavity—Scaling, Amplification, and Coherence

Scaling, coherence, and amplification of a subwavelength surface plasmon micropillar optical cavity have been studied using 3-D finite-difference time-domain calculations. Two experiments have also been conducted for the demonstration of the gain-assisted propagation of surface plasmon polaritons in a planar metal–semiconductor waveguide and the enhancement of the cavity-$Q$ factor in a subwavelength surface plasmon micropillar cavity.