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Simulation results of near infrared (100- to 200-THz) fishnet-structure negative-index metamaterials (NIMs) with single and multiple functional layers exhibit bi-anisotropy - inhomogeneous asymmetry - due to the presence of a sidewall-angle. The influence of sidewall-angle resulting from realistic fabrication processes is investigated through the retrieved effective parameters by both a three-dimensional finite-difference time-domain (FDTD) method and a rigorous coupled wave analysis (RCWA).

Evanescent-wave illumination is applied to synthetic-aperture microscopy on a transparent solid substrate to extend the resolution limit to lambda/2(n+1) (where n is the substrate refractive index) independent of the lens NA. Using a 633 nm source and a 0.4 NA lens, a resolution to 150 nm (lambda/4.2) is demonstrated on a glass (n = 1.5) substrate. Further extension to approximately 74-nm resolution (lambda/8.6) is projected with a higher index substrate (n = 3.3)., ((c) 2008 Optical Society of America)

The numerical analysis of finite planar metal-insulator-metal waveguide structures using the transfer-matrix formalism reveals both bound and leaky surface plasmon (SP) modes. The dispersion relations, propagation lengths and confinement factors of these SP modes are presented. The highest energy SP mode consists of non-radiative (bound) and radiative (leaky) portions separated by a spectral gap. The leaky regime is further divided into antenna and reactive mode regions. The antenna mode may be used for both free-space coupling and beam steering devices.

We use finite-difference time-domain (FDTD) simulations to demonstrate enhanced infrared absorption in a photodetector covered with a microstructured metal film consisting of a metal-plasmon grating collector/ concentrator and sub-wavelength detector well; for circular gratings we use radial FDTD, and for linear gratings we use two-dimensional FDTD. We identify a figure of merit to quantify the improvement in signal-to-noise ratio of such a detector scheme. We optimize grating parameters for a circular grating surrounding a simple hole, showing that the signal-to-noise ratio can be improved by a factor of as much as 5.2, whereas the signal-to-noise improvement for comparable linear gratings is at most 1.7. In the case of the circular grating, this result is achieved with more than 400 times as much light absorbed in the hole as with a metal film but no grating.