Excitation Of Surface Electromagnetic Waves Research Articles

The Use of Plasmonic Spectroscopy for Detecting Ultra-Low Concentrations of Substances

This paper presents the results of research into the excitation of a surface electromagnetic wave (SEW) in Au/AgI and Au/Ag films contacting aqueous solutions of hydrogen peroxide (H2O2) and sodium chloride (NaCl). The dependences of the SEW excitation angle in the Kretschmann configuration on the interaction time of the solution with the metal film have been obtained. The effect of an aqueous H2O2 solution on the AgI and Ag film under prolonged exposure has been demonstrated. It has been shown that the dynamics of the excitation angle can be used to estimate the concentration of solutions with low and ultra-low concentrations. As an example, the results of using the technique for the analysis of aqueous solutions of NaCl are presented.

Determination of the threshold sensitivity of a deposited dielectric film thickness control method based on surface plasmon resonance effect

The lower boundaries of the real time measuring range of the dielectric film thickness on the sensor surface, the principle of which is based on the effect of the excitation of surface electromagnetic waves (SEW), are determined. The simulation was performed for materials with high and low refractive index.

Parametric Excitation of Surface Electromagnetic Waves by a Pump Wave Incident Obliquely on a Semi-Infinite Plasma

Parametric excitation of surface waves by an s-polarized electromagnetic wave incident obliquely on a semi-infinite supercritical plasma is considered. The growth rates and thresholds of the instability associated with the decay of the pump wave into two surface electromagnetic waves are calculated as functions of the incidence angle and plasma electron density. It is shown that the instability growth rate depends linearly on the electric field of the pump wave and is maximal at a plasma electron density slightly exceeding the critical density.

Selective Excitation of the Microwave Sommerfeld—Zenneck Surface Wave on a Conductive Strip

Surface electromagnetic waves (SEWs) on imperfect conductors proposed by A. Sommerfeld and J. Zenneck in the early 20th century have remained unrecognized by academic science for almost a hundred years due to a regrettable misunderstanding of theorists and unsolved radio communication problems. Recognition could have come much earlier if radiophysicists had been able to apply excitation of SEWs in the centimeter range of microwaves, generation of which became possible in the first half of the 20th century with development of radar. Radiophysical experiments on excitation of surface electromagnetic waves on conductors in the centimeter range of radio waves are presented. A method for selective excitation of SEWs is described. Its essence is that the space radio wave radiation is suppressed by screening while the SEW on the conductive strip is excited by isolated currents launched through a slit in the screen.

Near field evidence of backward surface plasmon polaritons on negative index material boundaries

We present a detailed analysis about the electromagnetic response of a metamaterial surface with a localized defect. The excitation of electromagnetic surface waves leads to a near-field distribution showing a periodic dependence along the metamaterial surface. We find that this periodic pattern provides a direct demonstration of the forward or backward surface wave propagation.

Plasmon–polariton assisted formation of nanotip arrays on surfaces of bulk aluminum upon femtosecond laser irradiation

Two new methods for the formation of nanotip arrays under the action of single or double femtosecond laser pulses on a surface of bulk aluminum are presented. It is shown that a key role in the formation of nanotips is played by the excitation of surface electromagnetic waves and their mutual interference, and by their interference with the exciting electromagnetic field of the laser pulse.

Excitation of surface electromagnetic waves at planar interfaces between two gyrotropic media

We discuss whether it is possible to excite electromagnetic surface waves within a structure consisting of two plane-parallel, twinned, anisotropic, gyrotropic layers with opposing gyration vectors that are perpendicular to the interface between these layers. We calculate the reflection and transmission coefficients of such a structure when the incident exciting bulk wave arrives at an oblique angle from a medium with higher optical density. We study the distribution of electromagnetic field energy density within the structure at peak transmission adjacent to, and within, the total-reflection zone.

Excitation of Electromagnetic Surface Waves at A Conductor-Plasma Interface by An Electron Beam

Electromagnetic surface waves are driven to instability on a conductor plasma interface via Cerenkov and fast cyclotron interaction by an electron beam. A dispersion relation and the growth rate of the instability for this process has been derived. Numerical calculations of the growth rate and unstable mode frequencies have been carried out for the typical parameters of the surface plasma waves. The plasma and beam responses are obtained using fluid treatment and the growth rate is obtained using the first-order perturbation theory. The growth rate increases with the beam density and scales as one-third power of the beam density in Cerenkov interaction and is proportional to the square root of beam density in fast cyclotron interaction. In addition, the real frequency of the unstable wave increases with the beam energy and scales as almost one half power of the beam energy. The effect of the plasma parameters and the strength of the external magnetic field on unstable frequencies and growth rates are analyzed.

Sensitivity enhanced biosensor using graphene-based one-dimensional photonic crystal

In this paper, we propose and analytically demonstrate a biosensor configuration based on the excitation of surface electromagnetic waves in a graphene-based one-dimensional photonic crystal (1D PC). The proposed graphene-based 1D photonic crystal consists of alternating layers of high (graphene) and low (PMMA) refractive index materials, which gives a narrow angular reflectivity resonance and high surface fields due to low loss in PC. A differential phase-sensitive method has been used to calculate the sensitivity of the configuration. Our results show that the sensitivity of the proposed configuration is 14.8 times higher compared to those of conventional surface plasmon resonance (SPR) biosensors using gold thin films. This novel and effective graphene-based 1D PC will serve as a promising replacement of metallic thin film as a sensor head for future biosensing applications.

Tunable Plasmon-Induced Transparency of Double Continuous Metal Films Sandwiched with a Plasmonic Array

Making a continuous metal film with near-unity transparency has received more and more attention in recent years because of its potential applications for various optoelectronic devices. Here, we theoretically show that a high tunable plasmon-induced transparency metal film structure can be performed by double continuous metal films inserted with a two-dimensional hexagonal lattice array of plasmonic nanopariticles. The proposed structure shows near-unity anti-reflection and intensively enhanced transmission via the cooperative effects of strong resonant near-field light input and output coupling by the plasmonic array and the excitation of surface electromagnetic waves of the metal films. The optical response can be efficiently mediated by varying the sizes of nanoparticles and the separated distance between the metal array and the metal films. With the merits of high transparency, sub-wavelength sizes and wholly retained metal characteristics including high conductivity via using the pure metallic materials, the structure proposed here suggests various potential applications in optoelectronic integrated circuits.

Probing losses of dielectric multilayers by means of Bloch surface waves

We exploit the excitation of electromagnetic surface waves on high-quality dielectric multilayers to measure the very low extinction coefficient of the structures, with a resolution down to 4·10(-7) and in a simple optical configuration. The effect of exposition to a rhodamine 6G solution in water and ethanol is also reported, including dye adsorption in the layers and bleaching upon resonant excitation.

Local field enhancement on metallic periodic surface structures produced by femtosecond laser pulses

Periodic surface structures on aluminium are produced by femtosecond laser pulses for efficient excitation of surface electromagnetic waves using a strong objective (). The local electromagnetic field enhancement on the structures is measured using the technique of surface-enhanced Raman scattering from pyridine molecules.

Excitation of surface electromagnetic waves in a graphene-based Bragg grating

Here, we report the fabrication of a graphene-based Bragg grating (one-dimensional photonic crystal) and experimentally demonstrate the excitation of surface electromagnetic waves in the periodic structure using prism coupling technique. Surface electromagnetic waves are non-radiative electromagnetic modes that appear on the surface of semi-infinite 1D photonic crystal. In order to fabricate the graphene-based Bragg grating, alternating layers of high (graphene) and low (PMMA) refractive index materials have been used. The reflectivity plot shows a deepest, narrow dip after total internal reflection angle corresponds to the surface electromagnetic mode propagating at the Bragg grating/air boundary. The proposed graphene based Bragg grating can find a variety of potential surface electromagnetic wave applications such as sensors, fluorescence emission enhancement, modulators, etc.

Effect of an external alternating electric field non-monochromaticity on parametric excitation of surface ion cyclotron X-modes

The application of an external alternating electric field in the range of ion cyclotron frequencies is a well-known method for the excitation of surface electromagnetic waves. The present paper is devoted to the development of a kinetic theory of parametric excitation of these eigenwaves propagating across an external steady magnetic field along the plasma boundary at the second harmonic of the ion cyclotron frequency. Unlike previous papers on this subject, parametric excitation of surface ion cyclotron X-modes is studied here under the condition of non-monochromaticity of an external alternating electric field. Non-monochromaticity of the external alternating electric field is modeled by the superposition of two uniform and monochromatic electric fields with different amplitudes and frequencies. The nonlinear boundary condition is formulated for a tangential magnetic field of the studied surface waves. An infinite set of equations for the harmonics of a tangential electric field is solved using the approximation of the wave packet consisting of the main harmonic and two nearest satellite harmonics. Two different regimes of instability have been considered. If one of the applied generators has an operation frequency that is close to the ion cyclotron frequency, then changing the amplitude of the second generator allows one to enhance the growth rate of the parametric instability or to diminish it. But if the operation frequencies of the both generators are not close to the ion cyclotron frequency, then changing the amplitudes of their fields allows one to decrease the growth rate of the instability and even to suppress its development. The problem is studied both analytically and numerically.

Biosensing using surface electromagnetic waves in photonic band gap multilayers

Abstract A biosensor based on the excitation of surface electromagnetic waves in photonic band gap multilayer films is demonstrated. The operating principle of this device is similar to surface plasmon biosensors with the key difference that a photonic band gap film replaces the metal film as the medium in which surface electromagnetic waves are excited. The use of photonic band gap films offers a number of advantages. First, the surface wave resonance is much sharper leading to the potential of greatly enhanced sensitivity. Second, the properties of the photonic band gap material can be engineered to make a sensor that operates at any wavelength. The experiments reported here are conducted with a surface wave resonance at 470 nm, a wavelength not generally accessible with surface plasmon sensing. Finally, the photonic band gap films are more mechanically robust than metal films and they offer new substrates for surface chemistry. The paper describes the design of the photonic band gap films, the surface chemistry and biology to create sensing chips, and the spectroscopic experimental configuration used to observe and track the surface mode resonance. Experimental results are presented on refractive index sensing, antibody–antigen reactions, and DNA binding.

Electromagnetic wave refraction on the interface of absorptive and transparent isotropic media and non-resonant excitation of surface waves

New formulae for the angles of refraction at the interface of the absorbing/transparent isotropic media are derived from Maxwell's equations. Using the time-averaged Poynting vector for the direction of the beam of light, the noncoincidence of incidence and refraction planes is predicted for the mixed polarization of incident wave. The angle between the refracted beam and incidence plane is especially large for the condition of non-resonant excitation of surface electromagnetic waves at a flat interface of absorptive-transparent media.

Excitation of surface electromagnetic waves at an anisotropically conducting vacuum-metamaterial interface by the attenuated total internal reflection method

The excitation of well-localized oblique surface waves above the surface of a dielectric with a one-dimensional array of perfectly conducting wires is studied theoretically using the attenuated total internal reflection method. It is assumed that the distance between the wires and their diameter are much smaller than the surface wavelength. The frequencies of excited surface waves are much lower than the plasma frequency of the metal, and their electric field is orthogonal to the wires. It is shown that such surface waves can be excited with the help of a homogeneous TM wave as well as with the help of a homogeneous wave with an electric field polarized perpendicularly to the wires. It is found that in the course of excitation of oblique waves, the incident TM wave is partly polarized into a wave of the TE type.

Fluorescence emission enhanced by surface electromagnetic waves on one-dimensional photonic crystals

An appreciable increase in the fluorescence emission of an organic chromofore is obtained by exploiting the local field enhancement at the surface of one-dimensional photonic crystals after excitation of surface electromagnetic waves (SEW). Using a properly designed photonic crystal consisting of alternating a-Si1−xNx:H layers with different nitrogen content, efficient emission of R6G dye spun on the surface of the photonic crystal is detected and the intensity spatial distribution of the SEW is visualized by means of far-field fluorescence microscopy. Our results demonstrate potential applications in enhanced fluorescence microscopy with an increased sensitivity and spectral selectivity.

A waveguide slit array antenna fabricated with subwavelength periodic grooves

This paper presents a waveguide slit array antenna with high gain and narrow beamwidth. This antenna is formed by subwavelength slits surrounded with periodic grooves. The far field radiation characteristics of the improved antenna are investigated. Simulation results show that the gain of the antenna with a designed working frequency is improved by 11dB and a strong beam can be obtained. The physical mechanism for the performance improvement is governed by the resonance excitation of surface electromagnetic waves and can be well described by the coherent superposition of power radiated from the grooves and central slits.

Excitation of backward Tamm states at an interface between a periodic photonic crystal and a left-handed metamaterial

We study the excitation of electromagnetic surface waves in a slab of a left-handed metamaterial separating a one-dimensional periodic photonic crystal and a homogeneous dielectric medium, the so-called surface Tamm states. We show that such a layered structure can exhibit a giant lateral Goos-H\anchen shift of the scattered beam accompanied by a splitting of the reflected and transmitted beams due to the resonant excitation of surface waves at the interfaces between the left-handed metamaterial and photonic crystal. The beam shift can be either positive or negative, depending on the type of the surface Tamm states excited by the incoming beam.