Extraordinary Transmission Properties Research Articles

High-fidelity fabrication of plasmonic nanoholes array via ion-beam planarization for extraordinary transmission applications

Plasmonic nanoholes are a kind of important building blocks for practical plasmonic applications due to their unique properties supporting extraordinary transmission and strong field enhancement. However, the reliable fabrication of plasmonic nanoholes with high-fidelity geometry, especially in thick metallic film, is still challenging with the current wet lift-off or focused-ion beam process. In this work, we demonstrate a process combining negative-tone electron-beam lithography, metal sputtering and flood ion-beam planarization to reliably fabricate plasmonic nanoholes. Compared to existing lift-off process, it has the advantages of 100% yield, uniform geometry and smooth structural edges. In contrast to focused-ion beam process, the current approach has apparently higher throughput and structural fidelity. Plasmonic nanoholes with different geometries, materials and sizes are reliably fabricated to demonstrate the advantages of this approach. The extraordinary transmission properties and their potential for refractive-index sensing are also demonstrated. This lithography-deposition-planarization strategy can also be extended to fabricate other optical structures such as optical metasurfaces and X-ray zone-plates.

Artificial birefringent metallic planar structures for terahertz wave polarization manipulation

We propose an artificial birefringent terahertz (THz) device constructed by subwavelength L-shaped hole arrays on a single metallic layer. This structure is able to work as a polarizer when the incident frequency is between the cut-off frequencies of two eigenmodes. When the incident wave is beyond cut-off frequencies of these two modes, it can be designed as an efficient half- or quarter-wave plate with extraordinary transmission properties. A big effective index difference from 0.254 to 0.768 is obtained using a subwavelength-thick planar structure, which can reduce the thickness of the device to one tenth of conventional quartz birefringent crystals for THz waves.

Influence of skin depth on the transmission properties of arrays of metallic subwavelength holes in the visible spectral

Abstract The extraordinary transmission properties of optical light through arrays of subwavelength metal holes have been investigated. The effects of geometrical parameters and dielectric materials filling in the hole on transmission properties have been given and discussed. The results demonstrate that at optical frequencies the skin depth of metal is comparable to the subwavelength hole size and should be taken into account. There may exist an optimal hole width and lattice constant, where transmittance reach the maximum. As the refractive index of dielectric materials filling in the hole increases, the transmittance spectra increases and shows more peaks.

Analysis of the extraordinary transmission properties of arrays of subwavelength holes on a metal film in the terahertz region

The extraordinary transmission properties of terahertz waves through arrays of subwavelength holes on a metal film have been investigated. The effects of the geometrical parameters and dielectrics filling the hole on transmission properties have been explored. The results show that the resonance peak shifts to long wavelength as the hole width and lattice period constant increase. As the refractive index of the dielectric materials filling the hole increases, the transmittance increases and the resonance peak wavelength changes to low frequency. The phase retardation can be flexibly changed by varying the geometrical parameters and dielectric materials filling in the hole.

Resonant Transmission of Light Through Subwavelength Holes in Thick Metal Films

In this paper, we study how extraordinary transmission through an array of holes in a metallic film appears as a function of the number of holes and their distribution. We have used a theoretical formalism able to analyze the optical properties of finite collections of apertures placed at arbitrary positions in a metallic film. First, we describe how the total transmission in a hexagonal two-dimensional hole array evolves as the number of holes in the array is increased. Second, we study the extraordinary transmission appearing in a single one-dimensional chain of holes. We find that the transmission through this structure is very sensitive to the incident polarization. Third, we show that a single hole flanked symmetrically by two finite chains of dimples can also present extraordinary transmission properties

Role of electromagnetic trapped modes in extraordinary transmission in nanostructured materials

We assert that the physics underlying the extraordinary light transmission (reflection) in nanostructured materials can be understood from rather general principles based on the formal scattering theory developed in quantum mechanics. The Maxwell equations in passive (dispersive and absorptive) linear media are written in the form of the Schr\"{o}dinger equation to which the quantum mechanical resonant scattering theory (the Lippmann-Schwinger formalism) is applied. It is demonstrated that the existence of long-lived quasistationary eigenstates of the effective Hamiltonian for the Maxwell theory naturally explains the extraordinary transmission properties observed in various nanostructured materials. Such states correspond to quasistationary electromagnetic modes trapped in the scattering structure. Our general approach is also illustrated with an example of the zero-order transmission of the TE-polarized light through a metal-dielectric grating structure. Here a direct on-the-grid solution of the time-dependent Maxwell equations demonstrates the significance of resonances (or trapped modes) for extraordinary light transmissio