Long-range surface plasmons in dielectric-metal-dielectric structure with highly anisotropic substrates

Abstract

We present a theoretical study of long-range surface plasmons propagating in a thin metallic film clad between two identical uniaxial anisotropic dielectric crystals. We show that the proper orientation of the optical axis of the crystal with respect to the metal surface enhances the propagation length of surface plasmons. Since the proper orientation depends on surface plasmon frequency, we give the results for the propagation length in a wide range of frequencies, including the telecommunication region. To increase the role of anisotropy, we consider artificial substrates from photonic crystals, which possess an order of magnitude stronger anisotropy than the natural optical crystals. We propose Kronig-Penney model for plasmonic crystal where the substrate is a periodic sequence of dielectric delta peaks. In this model the dispersion relation for surface plasmon has a band structure where the band width tends to zero when the frequency approaches the resonant frequency.

Leaky Surface Plasmon Polariton Modes at an Interface Between Metal and Uniaxially Anisotropic Materials

“…Nagaraj and Krokhin investigated long-range SPPs in dielectric-metal-dielectric structure with anisotropic substrates [9], but only transverse magnetic (TM) waves for the case of the optic axis perpendicular to the plane of the interface were considered. Liscidini and Sipe conducted a theoretical study of SPPs in a configuration in which a metal layer is on top of an anisotropic dielectric [10] and discovered the existence of quasiguided SPPs with numerical demonstration of the coupling of a TM-polarized incident beam to such SPP in the Kretschmann configuration at surface plasmon resonance.…”

Anisotropic propagation of surface plasmon polaritons induced bypara-sexiphenyl nanowire films

“…The next target of investigation may be the experimental verification of interesting properties of SPPs at a metal-anisotropic dielectric interface predicted by recent theoretical analyses, such as the polarization hybridization 8 and the long propagation lengths. 7,10 …”

“…Under this assumption the propagation of SPPs for a given frequency is isotropic, i.e., the magnitude of the in-plane wave vector of a SPP is independent of its direction. However, recent theoretical studies [7][8][9][10][11] predict that interesting novel properties of SPPs emerge when the dielectric is optically anisotropic. The angle between the SPP propagation and the optical axis of the anisotropic dielectric comes into play and the magnitude of the SPP in-plane wave vector becomes a function of the angle.…”

“…Krokhin et al 7 have shown that the SPP propagation length is increased when the optical axis is properly oriented. Very recently, Nagaraj and Krokhin 10 extended the analysis to a symmetric dielectricmetal-dielectric structure with anisotropic dielectrics and predicted a 20-fold increase in the propagation length of long-range SPPs compared with that of SPPs at a single dielectric-metal interface. Existence of quasiguided SPP 11 and scattering-free plasmonic optics 9 at an interface between an anisotropic dielectric and metal have also been the subjects of theoretical analyses.…”

Novel Plasmonic Probes and Smart Superhydrophobic Devices, New Tools for Forthcoming Spectroscopies at the Nanoscale

“…This is the basis of their peculiar properties. The confinement of the electromagnetic wave quite below the classical diffraction limit and a favorably long propagation length are the most important for applications in engineered nanostructures [36,37]. SPPs can be exploited to efficiently transfer energy, outdoing other non-collective classical electronic transport phenomena, such as thermal or electric conduction.…”