Finite-thickness effects in plasmonic films with periodic cylindrical anisotropy [Invited]

Abstract

Finite-thickness effects are analyzed theoretically for the plasma frequency and associated dielectric response function of plasmonic films formed by periodically aligned, infinitely thin, identical metallic cylinders. The plasma frequency of the system is shown to have the unidirectional square-root-of-momentum and quasilinear momentum spatial dispersion for the thick and ultrathin films, respectively.This spatial dispersion and the unidirectional dielectric response nonlocality associated with it can be adjusted not only by the film material composition but also by varying the film thickness, the cylinder length, the cylinder-radius-to-film-thickness ratio, and by choosing the substrates and superstrates of the film appropriately. Application of the theory developed to the finite-thickness periodically aligned carbon nanotube films is discussed.

Transdimensional epsilon-near-zero modes in planar plasmonic nanostructures

“…Similar to truly 2D and quasi-2D materials such as graphene and transition metal dichalcogenide monolayers [8,15], plasmonic TD materials are also expected to show the extreme sensitivity to external fields, making possible advances such as novel parity-time symmetry * Corresponding author email: ibondarev@nccu.edu breaking photonic designs [16] that can further develop the fields of plasmonics and optical metasurfaces [17,18]. However, while some predictions on tunability, anomalous dispersion, and strong light confinement in ultrathin plasmonic films have been made [19][20][21][22][23] much remains unclear about their nonlinear optical response, quantum near-field and nonlocal effects.Here we use macroscopic quantum electrodynamics (QED) and the confinement-induced nonlocal Drude dielectric response model based on the Keldysh-Rytova (KR) pairwise electron interaction potential [21][22][23], to study epsilon-near-zero (ENZ) modes and their coupling to a point-like atomic dipole emitter (DE) near the surface of the metallic film in the TD regime. The ENZ modes are vertically confined SP modes of frequency ω(k) reaching the plasma oscillation frequency ω p of the film whereby its dielectric response function crosses zero [12].…”

Emergent Properties of Macroscale Assemblies of Carbon Nanotubes

“…Another unusual quality of nanotube cQED is that nanotubes can play a dual role as an emitters and optical cavities. [18,[27][28][29][30] Here, etched segments of nanotubes function as plasmonic optical cavities, in which charge oscillations along the nanotubes couple to the electromagnetic field and strongly confine light. In this type of intrinsic cQED system (i.e., one in which the cavity and the emitters comprise the same material), plasmon-exciton coupling in nanotubes has recently achieved normalized Rabi coupling strengths (Ω/ω 0 ) as high as 75%.…”

Controlled Exciton-Plasmon Coupling in a Mixture of Ultrathin Periodically Aligned Single-Wall Carbon Nanotube Arrays

“…CNs can be approximated by that of two uniformly charged rings of radius R of the respective n-th and ℓ-th tubules 15 . We consider that the dielectric medium embedding a periodic array has much greater dielectric permittivity than the substrate and superstrate permittivities.…”

“…We consider that the dielectric medium embedding a periodic array has much greater dielectric permittivity than the substrate and superstrate permittivities. In this case 16 , the Coulomb interaction in the film increases strongly as the film thickness decreases, making the Coulomb interaction independent of the vertical coordinate component [15][16][17][18][19] . Although this vertical confinement leads to the reduction of the effective dimensionality from three to two, the thickness d is still a variable parameter there to represent the finite vertical size of the system, which the dielectric response of the film depends on.…”