TE Mode Wave Research Articles

Polarization conversion of free-space light by metasurface-dressed on-chip waveguide

Emerging guided wave-driven metasurface has made outstanding contributions as bridges between guided waves and light in free space. However, people usually convert TE mode wave into y-polarization wave without achieving cross-polarization. In this work, an all-dielectric guided wave-driven metasurface was proposed and simulatively investigated, which can convert TE mode wave into x-polarization. There is a set of gradually rotating silicon single-split-rings (SSRs) embedded in a silicon nitride waveguide, which is the key of cross-polarization. Plus an array of silicon meta-atoms which can cover the full 2π phase shift, they form our metasurface together. As a proof of concept, anomalous deflection control of cross-polarized extracted wavefront and a one-dimensional focusing lens are numerical demonstrated. Our findings could lead to more flexible control of waves between free space and waveguide, and provide an ideal platform applied in photonic integrated chip.

Broadband refractive index sensor based on localized surface plasmon for highly sensitive detection of fluid pressure

Localized surface plasmon resonance (LSPR) in gold (Au) nanoparticles is the research hotspot in various fields, due to its high chemical and physical stability, ease of preparation and multiple optical properties. However, the anisotropic response to polarized light of LSPR has been rarely studied. Here, we report optical refractive index sensors based on the polarization sensitive response of LSPR in gold nanoparticles, and its application in the highly sensitive detection of fluid species and hydraulic pressure. The polarization-sensitive absorption characteristics of the interfacial nanoparticles rendering it different absorption properties for TM and TE mode waves under the condition of total reflection, which is also strongly affected by the refractive index of medium n2 in contact with it. On this basis, the refractive index sensor based on LSPR in gold nanoparticles is successfully realized. In addition, the refractive index sensor features broadband response (from 200 to 1000 nm) in a wide range of incident angle δ (from −10° to 25°), exhibiting great application potential in various scenarios. To evaluate the practical applicability of the proposed sensor, we constructed an optical refractive index sensing system that can distinguish between liquid species and accurately detect hydraulic pressure in real time.

Cloaking, scattering and coherence properties of epsilon-near-zero materials in transformation optics

This paper shows that epsilon-near-zero (ENZ) / mu-near-zero material can be obtained by using the transformation optics (TO) approach. It shows that when a line is stretched to a cylinder the z component of permittivity and permeability is zero, while the rho and phi components are equal to one. Hence in the presence of a TE mode wave, the cylinder is equivalent to an isotropic ENZ column. We further show that some additional spatial mapping can be applied to eliminate or mimic the scattering of the ENZ cylinder. To verify our proposal, a rigorous analysis based on Maxwell’s equations and numerical simulations based on the finite element method are provided. Finally, cloaking and coherence enhancement are taken as examples to demonstrate potential applications of the ENZ material from the viewpoint of TO.

Intensity depending on object distance in a two-dimensional photonic crystal

The propagation of electromagnetic (EM) waves in two-dimensional triangular-lattice photonic crystals (PCs) is investigated through dispersion characteristics analysis and numerical simulation of field pattern. The designed PC structure can exhibit all angle negative refraction in the second band. A flat superlens formed from such a PC has been designed and its imaging properties have been investigated systematically. Good-quality images and focusing, with relative refractive index of −1, have been observed in this system for TE mode waves. In contrast to the images in near-field region for the lowest valence band, non-near-field images, explicitly following the well-known wave-beam negative refraction law, have been demonstrated. The relation between the intensity of the image and the object distance has also been discussed in this paper. The extensive applications of such a phenomenon to optical devices are anticipated.

A novel separable backward–central FDTD method

AbstractIn this paper, we present a novel separable backward–central FDTD (SBC‐FDTD) method in which the backward and central differences are used to discretize both time and spatial directive of the Maxwell's equations. For the type of problem in which the FDTD cell size in one direction is much smaller than those in the other directions, the time step in the proposed separable backward‐central FDTD technique can be chosen based on the largest cell size instead of the smallest one used in the conventional Yee's FDTD. Compared to the alternating‐direction implicit FDTD (ADI‐FDTD), although the proposed approach is not unconditionally stable, it allows us to explicitly solve electric and magnetic fields in one direction. Both the numerical experiments and the stability property demonstrate that the proposed scheme is stable and accurate. A TE mode wave is used to validate the proposed technique. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 212–215, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21308

A TB-Mode Accelerator

An accelerator is proposed in which a TE-mode wave is used to drive charged particles in contrast to the usual linear accelerators in which longitudinal electric fields or TM-mode waves are supposed to be utilized. The principle of the acceleration is based on the Vp × B acceleration of a dynamo force acceleration. That is, a charged particle trapped in a transverse wave feels a constant electric field (Faraday induction field) and subsequently is accelerated when an appropriate magnetic field is externally applied in the direction perpendicular to the wave propagation. A pair of dielectric plates is used to produce a slow TE mode. Discussions will be given on what the conditions of the particle trapping are and how to stabilize the particle orbit.

Potentialities of electric and magnetic wave tilt measurements

A comparative study of TM and TE mode wave tilt magnitude and phase variations in the extended frequency range have been carried out for some electrical parameters of the earth's surface as a half‐space model. The TM and TE mode wave tilts show complementary behavior in the extended frequency range. The problem of excitation and propagation of TE mode wave has been discussed. It is shown that the measurement of Wm and We in the extended frequency range would reveal the surface and subsurface features.

Wave-tilt characteristics of TE-mode waves

The dependence of TE-mode wave-tilt on frequency and altitude of measurement, and the resistivity and dielectric constants of the ground have been investigated. Computational results showing the influence of these parameters on the amplitude and phase of the wave-tilt over a homogeneous half-space earth model have been presented. In contrast to TM-mode waves, the wave-tilt effects for TE-mode are stronger in the lower frequency region. In the lower frequency range, the amplitude decreases with the increase in resistivity of the ground, whereas it increases for an increase in dielectric constant value. When the displacement currents are ignored, the magnitude of amplitude of wave-tilt is reduced considerably. The altitude of measurement has minimal effect on the amplitude, but the phase changes appreciably in some cases.

Nonreciprocal Remanence Phase Shifters in Rectangular Waveguide

Three types of nonreciprocal remanent phase shifters in rectangular waveguide are described which are approximated by a simple model consisting of twin ferrite slabs symmetrically placed in rectangular waveguide and separated by a dielectric rib. The model has been analyzed with the assumption that a fundamental TE mode wave propagates in the structure. Simultaneous solution of Maxwell's equations in the three regions of dielectric, ferrite, and air within the waveguide enables the characteristic equation to be formed. The characteristics of the model have been obtained with the aid of a computer as a function of dimensions, dielectric and magnetic constants, frequency, and power. The theoretical results are compared with experimental data obtained on a double toroid structure. Correction factors applied to the experimental data, which are necessary to account for differences between the practical structure and the ideal model, are discussed.

Propagation of Electromagnetic Waves in Rectangular Guides Filled with a Semiconductor in the Presence of a Transverse Magnetic Field

The characteristics of electromagnetic waves propagating in a semiconductor filled rectangular waveguide in the presence of a transverse magnetic field are studied. It is shown that only TE mode waves having y-independent field components (y being the direction of the steady magnetic field) and anomalous modes having all six field components can propagate. The propagation constant of waves characterized by a sinusoidal y dependence of fields is derived. Asymptotic expressions for the fields and the propagation constant are then obtained for the limiting case of a small external magnetic field and some recent experimental results are analyzed in this context.