Figure 2
From: Realization of Plasmonic Microcavity with Full Transverse and Longitudinal Mode Selection
Design and fabrication of SPP microcavity supporting a fundamental Gaussian mode.
(a) The SEM picture of the fabricated groove-pattern holographic mirror to focus SPP wave to a spot on the surface of gold thin film. (b) Experimental images of focusing a normally incident plane wave from free space into a SPP spot on the gold surface. (c) Morphology of the designed microcavity structure and calculated intensity distributions on the metal surface. The intensity distributions correspond to the modular square of electric field. The calculated field profile (e) in the 
plane with y = 240 nm and (g) along the x-axis with y = 240 nm and z = 0. (d) SEM picture of the fabricated SPP concave microcavity. Each holographic mirrors has a size of 20 × 20 μm2 and the cavity length is 16 μm. (f) Leaky-mode observation image of the SPP field pattern in the concave microcavity. Both simulations and experiments show formation of a fundamental Gaussian SPP mode confined within the microcavity and at the surface of gold thin film.
