Plasmons at the interface between a corrugated semiconductor film and a binary metallic superlattice

We investigate the minigaps of the dispersion relation of plasmon polaritons that propagate at the interface between a corrugated semiconductor film and a binary metallic superlattice. Minima of the reflectivity for p-polarized light are calculated and their frequencies are used to obtain the ‘optical’ dispersion relations which are compared with the corresponding electromagnetic dispersion curves, in the effective medium theory. Results show that the minigap enlarges with the corrugation strength.     

An additional kind of nonlinear s-polarized surface plasmon polaritons

We have explored the dispersion relations for s-polarized surface plasmon polaritons guided by a metal film sandwiched between a linear substrate and a cladding with an intensity-dependent refractive index. In contrast to a previous paper we found surface plasmon polaritons for this configuration which exhibit a definite power threshold and a limited range for permitted propagation constants as well.     

The surface plasmon polariton dispersion relations in a nonlinear-metal-nonlinear dielectric structure of arbitrary nonlinearity

The analytic surface plasmon polaritons(SPPs) dispersion relation is studied in a system consisting of a thin metallic film bounded by two sides media of nonlinear dielectric of arbitrary nonlinearity is studied by applying a generalised first integral approach.We consider both asymmetric and symmetric structures.Especially,in the symmetric system,two possible modes can exist:the odd mode and the even mode.The dispersion relations of the two modes are obtained.Due to the nonlinear dielectric,the magnitude of the electric field at the interface appears and alters the dispersion relations.The changes in SPPs dispersion relations depending on film thicknesses and nonlinearity are studied.     

Surface plasmon polaritons in metallo-dielectric meander-type gratings

The optical properties of a gold film deposited on a quartz substrate with periodic grooves were investigated theoretically. The main peculiarities of the spectra are due to the excitation of the surface plasmon polaritons (SPPs). It is shown that the empty lattice approximation (ELA) for the SPPs is well applicable for the structure of interest. Two different approaches for deriving the air-gold SPP dispersion curves are compared. Our special attention is focused on the wavelength region approaching the d-band in gold, where the dielectric function is of a strongly non-Drude-type.     

Squeezing visible light waves into a 3-nm-thick and 55-nm-long plasmon cavity

We demonstrate controlled squeezing of visible light waves into nanometer-sized optical cavities. The light is perpendicularly confined in a few-nanometer-thick SiO2 film sandwiched between Au claddings in the form of surface plasmon polaritons and exhibits Fabry-Perot resonances in a longitudinal direction. As the thickness of the dielectric core is reduced, the plasmon wavelength becomes shorter; then a smaller cavity is realized. A dispersion relation down to a surface plasmon wavelength of 51 nm for a red light, which is less than 8% of the free-space wavelength, was experimentally observed. Any obvious breakdowns of the macroscopic electromagnetics based on continuous dielectric media were not disclosed for 3-nm-thick cores.     

Far-field optical microscopy with a nanometer-scale resolution based on the in-plane image magnification by surface plasmon polaritons

A new far-field optical microscopy capable of reaching nanometer-scale resolution is developed using the in-plane image magnification by surface plasmon polaritons. This approach is based on the optical properties of a metal-dielectric interface that may provide extremely large values of the effective refractive index neff up to 10(3) as seen by surface polaritons, and thus the diffraction limited resolution can reach nanometer-scale values of lambda/2neff. The experimental realization of the microscope has demonstrated the optical resolution better than 60 nm at 515 nm illumination wavelength.     

Modification of the photoluminescence anisotropy of semiconductor nanowires by coupling to surface plasmon polaritons

We demonstrate efficient modification of the polarized light emission from single semiconductor nanowires by coupling this emission to surface plasmon polaritons on a metal grating. The polarization anisotropy of the emitted photoluminescence from single nanowires is compared for wires deposited on silica, a flat gold film, and a shallow gold grating. By varying the orientation of the nanowire with respect to the grating grooves, the large intrinsic polarization anisotropy can be either suppressed or enhanced. This modification is interpreted by the appearance of an additional emission channel induced by surface plasmon polaritons and their conversion to p-polarized radiation at the grating.     

Optical properties of metallo-dielectric deep trench gratings: role of surface plasmons and Wood-Rayleigh anomaly

We present optical measurements performed on a gold film deposited on deep subwavelength grooves etched in a quartz substrate at visible wavelengths where the Wood-Rayleigh (WR) anomaly and surface plasmon polaritons (SPs) are well separated. The measurements show that transmission of TM-polarized light through the slit array vanishes when SPs are excited at the air-metal interface, whereas the WR anomaly appears as small peaks.     

Selective enhancement of the hole photocurrent by surface plasmon–polaritons in layers of Ge/Si quantum dots

It is found that the integration of Ge/Si heterostructures containing layers of Ge quantum dots with twodimensional regular lattices of subwave holes in a gold film on the surface of a semiconductor leads to the multiple (to 20 times) enhancement of the hole photocurrent in narrow wavelength regions of the mid-infrared range. The results are explained by the light wave excitation of the surface plasmon–polaritons at the metal–semiconductor interface effectively interacting with intraband transitions of holes in quantum dots.     

Nonlinear s-polarized surface plasmon polaritons

We have examined the dispersion relations for s-polarized surface plasmon polaritons, guided by (a) the interface between a semi-infinite metal and dielectric medium, and (b) a metal film bounded by semi-infinite dielectric media for situations in which one or more of the dielectric media are characterized by an intensity-dependent refractive index. We found that s-polarized waves satisfy the dispersion relations for very thin metal films bounded by nonlinear dielectric media. These waves exist only for power levels above a threshold that depends on the material parameters. We also comment on the experimental feasibility of observing these waves.     

Long-range propagation of plasmon polaritons in a thin metal film on a one-dimensional photonic crystal surface

We present experimental results on ultralong-range surface plasmon polaritons, propagating in a thin metal film on a one-dimensional (1D) photonic crystal surface over a distance of several millimeters. This propagation length is about 2 orders of magnitude higher than the one in the ordinary Kretschmann configuration at the same optical frequency. We show that a long-range surface plasmon polaritons propagation may take place not only in a (quasi)symmetrical scheme, where a thin metal film is located between two media with (approximately) the same refraction index, but also in a scheme where the thin metal film is located between an appropriate 1D photonic crystal and an arbitrary (air, water, etc.) medium. The ultralong-range surface plasmon polaritons are potentially important for biosensors, plasmonics, and other applications.     

太赫兹表面极化激元

作为束缚于表面或界面的电磁波与极性元激发的耦合模量子,表面极化激元是克服衍射极限的核心物理.在紫外、可见以及近红外波段,表面等离子极化激元展现出了亚波长特性,具有高分辨成像等应用,并发展成为"表面等离子极化激元亚波长光学"学科;在中红外波段,表面声子极化激元发挥着同样的作用.太赫兹波段曾是人类认识的空白区域,近三十年来得以高速发展,其战略意义重大.具有克服衍射极限能力的太赫兹表面极化激元同样是小型化与集成化太赫兹器件,以及太赫兹超高分辨成像的重要物理基础.近几年来,对以石墨烯为代表的二维材料的研究突飞猛进,诞生了"石墨烯表面等离子极化激元亚波长光学"这门学科,并贡献于太赫兹领域.本文对可在太赫兹波段工作的人工超构材料、掺杂半导体、二维电子气、二维材料、拓扑绝缘体等结构材料的表面极化激元进行了较为全面的总结与介绍,为研制克服衍射极限的太赫兹集成光子学器件提供可资借鉴的物理基础.     

Gold film-terminated 3-dimensional photonic crystals

Hybrid metal-dielectric photonic crystals assembled from an opal film coated by a gold film are designed in order to realize optical spectra that emanate from mixing Bloch modes in the opal and surface plasmon polaritons in corrugated gold films. The photonic crystal provides a spatial template for the gold film profile and modifies the electromagnetic vacuum in the vicinity to the gold layer. Reflectance spectroscopy was applied to deconvolute the plasmonic and photonic bandgap components in the optical response of hybrid crystals as opposite to their mixed appearance in the transmission spectra.     

Dispersion of cylindrical surface plasmon polaritons in layered structures

The problem of the existence of cylindrical surface plasmon polaritons on thin metal conductors is considered. A dispersion relation is obtained and analyzed, the domain of existence of dispersion curve with a maximum is found, and parametric relations are derived.     

Scattering of surface plasmon-polaritons and volume waves by thin gold films

The specific features of elastic scattering of volume waves and surface plasmon polaritons by polycrystalline gold films have been investigated. An analysis of the relative scattered energy, power spectral density of surface roughness, and integral and angular dependences of scattering of waves of different nature indicates a strong nonradiative multiple scattering of surface plasmon polaritons in gold films. When roughness increases, this scattering leads to an increase in scattering isotropy and to a partial loss of structural information about gold films. The analysis of the scattered energy of surface plasmon polaritons with application of the data on multifractal dimension of gold surface indicates also that the radiative scattering of surface plasmon polaritons depends on both the rms surface roughness and the surface wave propagation length.     

Surface magnetic polaritons on uniaxial antiferromagnets

The dispersion relation of surface polaritons for a uniaxial antiferromagnet are calculated taking account of retardation. In the presence of an external magnetic field, one finds that inequivalent propagation occurs in the Voigt configuration (±n? × H₀). For a high frequency permeability smaller than a critical value, the surface polaritons in the ?n? × H₀ direction, where n? is the normal to the interface, merges in the same frequency domain as the bulk polaritons.     

Surface plasmon polaritons mediated by surface modes in a metal-based photonic crystal complex structure

A hybrid metal–organic–photonic crystal (PC), a gold film with a SU8 film on its top followed by a three-dimensional (3D) PC, was designed to exercise additional control upon the photon behaviors. Attenuated total reflection measurements demonstrate that the 3D PC plays a crucial role in the formation of significant optical properties of the metal-based hybrid and the reflectivity minimum in its reflectivity curve is, mostly, a result of synergetic action of the coupling of surface plasmon polaritons to surface modes and additional guided modes yielded in the resonant cavity composed of the gold film and the PC.     

Angle-resolved transmission measurements through anisotropic two-dimensional plasmonic crystals

We report on high-accuracy angle-resolved optical transmission measurements through anisotropic 2D plasmonic crystals made of gold films with large-area rectangular arrays of nanoscale square holes, deposited on GaAs substrates. The measurements reveal the dispersion relations of air-gold and gold-GaAs surface plasmon polaritons. The crystal anisotropy induces a separation between plasmonic modes propagating in different directions. Their symmetry and dispersion properties are discussed.     

Many-body effects in the binding energies of image states at surfaces

A study of the influence of many-body effects on binding energies and effective masses of image potential induced surface states is presented. The binding energies calculated using experimentally measured ε(ω) response functions show a dependence on the electron density different from that obtained using a plasmon model, and are in agreement with recent experimental data of diesen et al. [Phys. Rev. B33 (1986) 5241]. The effects of plasmon dispersion and single particle excitations on binding energies are evaluated with a simple model, and it is shown that they result in a strong cancellation in the range of r_s values where most experimental data have been obtained (r_s ≈ 3), if realistic values of the surface plasmon dispersion relation are used. Corrections to the effective masses due to many-body effects are shown to be of the order of 1%.     

Duality of Spoof Surface Plasmon Polaritons on the Complementary Structures of Ultrathin Metal Films

Complementary metal structures manifest a remarkable scattering feature, known as Babinet's principle. Meanwhile, for surface modes confined to one or two dimensions, the relation between the modes on complementary structures has not been thoroughly studied. Here, spoof surface plasmon polaritons supported on complementary metal films are systematically investigated. The duality of electromagnetism guarantees that these surface modes on complementary metal films possess precisely the same dispersion regardless of the geometry of the grooves, which is confirmed by both numerical simulations and experimental measurements. This work may open another avenue for spoof surface plasmon polaritons in both the theoretical and practical aspects.