Plasmonic Wires Research Articles

Coupling strength of complex plasmonic structures in the multiple dipole approximation

We present a simple model to calculate the spatial dependence of the interaction strength between two plasmonic objects. Our approach is based on a multiple dipole approximation and utilizes the current distributions at the resonances in single objects. To obtain the interaction strength, we compute the potential energy of discrete weighted dipoles associated with the current distributions of the plasmonic modes in the scattered fields of their mutual partners. We investigate in detail coupled stacked plasmonic wires, stereometamaterials and plasmon-induced transparency materials. Our calculation scheme includes retardation and can be carried out in seconds on a standard PC.

Plasmonic Resonance Effects for Tandem Receiving-Transmitting Nanoantennas

A nanoplasmonic "transceiver" was assembled to examine the efficiency of coupled plasmonic antennas and their resonance interactions. In particular, plasmonic focusing receiver antenna coupled to transmitting annular antenna having a short central plasmonic wire was measured. The receiver collected incoming radially polarized light and efficiently focused and coupled it to a rear side transmitter comprised of a short resonant plasmonic wire and annular aperture. Transmission spectra exhibited a substantial signature of the wire Fabry-Perot resonances. The wire antenna crossection was improved by nearly 3 orders of magnitude by the focusing antenna system.

Q-band tunable negative refractive index metamaterial using Sc-doped BaM hexaferrite

A simple structured tunable negative refractive index (n) metamaterial (TNIM) has been designed, fabricated and tested in a Q-band rectangular waveguide. The structure consists of one slab of single crystalline scandium-doped barium hexaferrite (Sc-BaM), aligned parallel to two rows of periodic copper wires. The magnetic field tunable passband is measured indicating the occurrence of negative n. The centre frequency of the 5 GHz wide passband, having a transmission peak of −13 dB, is shifted linearly from 40.9 to 43.9 GHz by varying the bias field (H) from 4.0 to 7.0 kOe. The impact of ferrite volume factor (FVF) of the Sc-BaM slab upon the performance of the TNIM composite has been studied qualitatively. A tradeoff effect is illustrated in which the desirable negative permeability (μ) of the ferrite is offset by the detrimental impact of its dielectric property in suppressing the negative permittivity (ε) of the nearby plasmonic wires.

A microstrip tunable negative refractive index metamaterial and phase shifter

A tunable negative refractive index metamaterial and miniature phase shifter have been designed and fabricated in a microstrip configuration for applications in radio frequency integrated circuits. The metamaterial consists of plasmonic copper wires and yttrium iron garnet slabs having a low insertion loss of 5dB at the center of the transmission band. The yttrium iron garnet material enables the magnetic field tuning of the negative refractive index in a dynamic frequency band from 7.0to11.0GHz. The insertion phase can be tuned by 45° continuously by varying the bias field from 3.8to4.6kOe at 9.0GHz.

Negative permeability and subwavelength focusing of quasi-periodic dendritic cell metamaterials

We present the design for a hexagonal cell made of quasi-periodic dendritic arranged collections of plasmonic metallic wires that may exhibit a resonant magnetic collective response. When such quasi-periodic dendritic cells are etched on a host medium, they may provide metamaterials with negative effective permeability. We also show that a clear point image is observed, as expected, with our left-handed metamaterials (LHMs) lens composed of metallic dendritic cells and wire strips. These prominent characteristics of quasi-periodic dendritic cells potentially enable us to prepare infrared or visible domain LHMs by using a general chemical method.