Transparent conducting electrodes (TCE) consisting of silver nanowires (SNW) with a single-layer graphene (SLG)
cover demonstrate higher optical transparency and lower sheet resistance than indium tin oxide (ITO) and are
comparable to the best reported results in TCEs. SNW layer is simulated using the spectral averaging of the FDTD
transmittance data from indiscriminately selected frames. Simulations are done for a number of frames until a
convergent set of averaged spectra is obtained. SLG layer is simulated separately and contributes to the total
transmittance as a multiplicative constant.
We have studied the ability of a lamellar near-field superlens to transfer an enhanced electromagnetic field to the far side
of the lens. In this work, we have experimentally and numerically investigated superlensing in the visible range. By
using the resonant hot-spot field enhancements from optical nanoantennas as sources, we investigated the translation of
these sources to the far side of a layered silver-silica superlens operating in the canalization regime. Using near-field
scanning optical microscopy (NSOM), we have observed evidence of superlens-enabled enhanced-field translation at a
wavelength of about 680 nm. Specifically, we discuss our recent experimental and simulation results on the translation of
hot spots using a silver-silica layered superlens design. We compare the experimental results with our numerical
simulations and discuss the perspectives and limitations of our approach.
Historically, the methods used to describe the electromagnetic response of random, three-dimensional (3D), metal-dielectric composites (MDCs) have been limited to approximations such as effective-medium theories that employ easily-obtained, macroscopic parameters. Full-wave numerical simulations such as finite-difference time domain (FDTD) calculations are difficult for random MDCs due to the fact that the nanoscale geometry of a random composite is generally difficult to ascertain after fabrication. We have developed a fabrication method for creating semicontinuous metal films with arbitrary thicknesses and a modeling technique for such films using realistic geometries. We extended our two-dimensional simulation method to obtain realistic geometries of 3D MDC samples, and we obtained the detailed near- and far-field electromagnetic responses of such composites using FDTD calculations. Our simulation results agree quantitatively well with the experimentally measured far-field spectra of the real samples.