Plane Dielectric Layer Research Articles

Microfluidic Lab-on-CMOS Packaging Using Wafer-Level Molding and 3D-Printed Interconnects.

Lab-on-a-chip (LoC) technologies continue to promise lower cost and more accessible platforms for performing biomedical testing in low-cost and disposable form factors. Lab-on-CMOS or lab-on-microchip methods extend this paradigm by merging passive LoC systems with active complementary metal-oxide semiconductor (CMOS) integrated circuits (IC) to enable front-end signal conditioning and digitization immediately next to sensors in fluid channels. However, integrating ICs with microfluidics remains a challenge due to size mismatch and geometric constraints, such as non-planar wirebonds or flip-chip approaches in conflict with planar microfluidics. In this work, we present a hybrid packaging solution for IC-enabled microfluidic sensor systems. Our approach uses a combination of wafer-level molding and direct-write 3D printed interconnects, which are compatible with post-fabrication of planar dielectric and microfluidic layers. In addition, high-resolution direct-write printing can be used to rapidly fabricate electrical interconnects at a scale compatible with IC packaging without the need for fixed tooling. Two demonstration sensor-in-package systems with integrated microfluidics are shown, including measurement of electrical impedance and optical scattering to detect and size particles flowing through microfluidic channels over or adjacent to CMOS sensor and read-out ICs. The approach enables fabrication of impedance measurement electrodes less than 1 mm from the readout IC, directly on package surface. As shown, direct fluid contact with the IC surface is prevented by passivation, but long-term this approach can also enable fluid access to IC-integrated electrodes or other top-level IC features, making it broadly enabling for lab-on-CMOS applications.

The Method of Integral Variational Relations in the Problem of Eigenwaves of a Plane Dielectric Layer Coated with Graphene

The Method of Integral Variational Relations in the Problem of Eigenwaves of a Plane Dielectric Layer Coated with Graphene

The Nonlinear Eigenvalue Problem of Electromagnetic Wave Propagation in a Dielectric Layer Covered with Graphene

The paper focuses on the problem of a monochromatic terahertz TE-polarized wave propagation in a plane dielectric layer filled with a homogeneous isotropic medium; one of the boundaries of the waveguide is covered with a layer of graphene. In fact, the paper aims to find the eigenwaves of the described waveguiding structure. On the one hand, in the study, energy losses both in the dielectric layer and in the graphene layer are neglected; the latter assumption is reasonable in the terahertz range of electromagnetic radiation (on which the paper focuses), where graphene has a strong plasmonic response and much less loss. On the other hand, this study takes into account the significant third-order nonlinearity resulting from the interaction of the electromagnetic wave with the charge carriers in the graphene layer. The paper aims to study the guiding properties of the above structure using primarily an analytical approach. The wave propagation problem is reduced to an eigenvalue problem, where one of the boundary conditions is nonlinear with respect to the sought-for function. The main result of the paper is a dispersion equation allowing for a waveguide of a given thickness to determine a set of its propagation constants and, consequently, a set of its eigenwaves. It is worth noting that the dispersion equation being written in an explicit form can be used to obtain deep qualitative results related to the solvability of the problem and the properties of its solutions. For example, in the paper, the existence of several propagation constants (and, consequently, the eigenwaves) of the studied waveguiding structure is proved under some conditions. Besides studying the problem analytically, the paper presents some numerical results as well. In particular, the presented figures demonstrate how the nonlinearity in graphene affects the propagation constants and eigenwaves, providing the dispersion curves and eigenwaves for nonlinear graphene as well as for the linear one.

Super-Operator Linear Equations and Their Applications to Quantum Antennas and Quantum Light Scattering

In this paper, we develop a resolvent method for super-operator equations with applications in quantum optics. Our approach is based on the novel concept of a linear super-operator acting on the Hilbert subspace of vector or scalar linear operators satisfying physically reasonable commutation relations. The super-operator equations for the electromagnetic (EM) field operators are formulated for the problems of quantum antenna emission and quantum light scattering by a dielectric body. The general solution of super-operator equation is presented in terms of the classical resolvent. In contrast to the classical case, it includes the ancillary components associated with the quantum noise even in the absence of absorption. The reason for this lies in the energy exchange between different spatial regions with various bases for the field presentation (which looks like losses or gain from the point of view of the correspondent region). A number of examples (a two-element dipole antenna, a plane dielectric layer, and a dielectric cylinder with a circular cross section) which demonstrate the physical mechanism of the appearance of noise are considered. It is shown that antenna emission or scattering transforms the coherent properties of quantum light. This leads to a new way of controlling coherence in a direction-dependent manner, a feature that can be useful in various applications of quantum technologies, including quantum radars and lidars, and quantum antennas.

The temperature state of a plane dielectric layer at constant voltage and fixed temperature of one of the surfaces of this layer

The paper formulates the nonlinear problem of steady‐state heat conduction at the constant electric potential difference on the surfaces of a plane dielectric layer with the temperature‐dependent heat conduction coefficient and electrical resistivity. A fixed temperature value is set on one of the layer surfaces, and the convective heat exchange with the ambient medium occurs on the opposite surface. The formulation of the problem is transformed to integral ratios, which allows the calculation of the temperature distribution over the layer thickness, governed by the monotonic and nonmonotonic functions. The quantitative assay of the temperature state of a layer of a polymer dielectric made of amorphous polycarbonate is given as an example and the analysis of nonuniformity of the absolute value of electric field intensity over the thickness of this layer.

Efficiency of Gaussian light beam transformation into a waveguide mode of a plane dielectric layer under frustrated total internal reflection.

On the basis of the 2D analytic theory of the phenomenon of frustrated total internal reflection for a Gaussian light beam, produced by the authors in the previous paper [J. Opt. Soc. Am. A32, 843 (2015)JOAOD60740-323210.1364/JOSAA.32.000843], the efficiency of waveguide mode excitation in a plane dielectric layer using a prism is considered. The influence of the initial beam half-width, of the thickness of a waveguide, and of its displacement from the prism base on excitation efficiency is investigated. The conditions of maximal efficiency are established.

Generalized mode solver for plasmonic transmission lines embedded in layered media based on the Method of Moments

This paper presents an integral equation formulation for the calculation of the propagation characteristics of plasmonic transmission lines embedded within a multi-layered structure. The Method of Moments (MoM) technique is adopted in this paper due to its superior advantages over other techniques including the finite difference and finite element methods. Plasmonic transmission lines consist of a number metallic strips of arbitrary shapes immersed within a stack of planar dielectric or metallic layers. These transmission lines can support one or more mode, each of which has its characteristic mode profile and it propagates with a certain propagation and attenuation constants. The developed solver is tested for different plasmonic transmission line topologies surrounded by various layered media. The obtained results are compared to CST commercial software for verification. Very good agreement between the proposed solver and CST has been observed. The developed MoM solver requires much smaller number of unknowns if compared with those based on Finite Difference Time Domain (FD-TD) or Finite Element Method (FEM) such as Lumerical and CST.

Transformation of the airy pulse at temporary jump of the dielectric permittivity of the medium

The spatio-temporal problem of interaction of the Airy electromagnetic pulse and a plane dielectric layer is solved in the case of a permittivity sharp change in a layer at zero moment of time. Expressions for the field inside the layer are obtained and the influence of the starting parameter on the position of the pulse inside the layer is shown. The evolution of the pulse in media with different refractive index is analyzed. A comparative analysis of the interaction of the Airy pulse with a plane layer between two dielectric media with a dielectric layer is carried out. The influence of pulse reflections from the layer boundaries on its shape and location is analyzed. From the analysis of the obtained results it follows that the choice of the initial space-time parameter affects the location of the pulse in the layer, and the transition of the signal to a medium with a larger (lower) permittivity results in the amplitude increase of oscillations and the main lobe shape change.

Broadband LWIR and MWIR metamaterial absorbers with a simple design topology: almost perfect absorption and super-octave band operation in MWIR band

Infrared absorbers are essential structures in the design of thermal emitters and thermal infrared imagers. In this study, we propose simple topologies of wideband metamaterial absorbers operating in the long-wave infrared or in the mid-wave infrared (MWIR) wavelengths of the electromagnetic spectrum where the atmosphere shows transparent behavior. Suggested metamaterial absorbers are mostly thin structures that consist of three functional layers from top to bottom: a periodically patterned metal layer, a planar dielectric layer, and a ground metal layer. The pattern of the top metal layer is four-fold symmetric to guarantee the polarization insensitivity of the absorber under normal incidence of light. In addition, a geometrically simple metamaterial pattern is preferred to facilitate the process of lithography. As titanium is known to be a high-loss metal, it is deliberately used at the top layer of the absorber to increase the overall absorption bandwidth. Highly satisfactory absorber results, such as almost perfect absorption and super-octave band operation are demonstrated, especially in the MWIR region. As oxidation of the top titanium layer may cause performance degradation in long-term use, a design modification is also suggested where a very thin protective coating layer is applied over the titanium metasurface.

REFRACTIVE INDEX DETERMINATION FOR A PLANE DIELECTRIC LAYER USING THE MEASUREMENTS OF TRANSMITTED BEAM INTENSITY

The aim of the present work is the theoretical justification of new refractive index determination technique for a homogeneous transparent plane dielectric layer. It uses intensity measurements for two polarizations of transmitting electromagnetic beam and does not take into consideration phase relationships and phase parameters of testing field at unknown thickness of a layer. For this purpose, the layer transmission energy coefficients for two linear polarizations of an electromagnetic beam, orthogonal and parallel to the plane of incidence, are studied to be dependent on the layer thickness and its refractive index. We have found the function of energy transmission coefficients for these polarizations, which does not depend on the layer thickness and is characterized bIt is shown that this function provides the opportunity to determine the layer refractive index uniquely. It can be made analytically using the inverse function, and also with the help of experimental calibration technique for the initial function. The influence of losses on the method efficiency is investigated, and it is established, that the presence of absorption causes appearance of separated zones of refractive index variation, where the method becomes inoperative. However, at absorption index values of the order of 10–5 the method can be applied, but in the bounded domain of refractive index variation. So, it is established that the proposed methods provides the opportunity to determine the refractive index of a plane dielectric layer under conditions of low and null value of absorption using the intensity measurements for two orthogonal polarizations of transmitting electromagnetic radiation.

Finite One-Dimensional Photonic Crystal with Gaussian Modulation: Transmission and Escape

This paper studied the transmission coefficient and escape frequencies in a system of planar dielectric layers where the refractive index changes from one layer to another through a Gaussian function. The wave equation with normal incidence is analyzed. For the calculations, the transfer matrix formalism is used. In a previous work, the transmission and escape problem for Gaussian electronic superlattices is investigated. Now it studied the electromagnetic modes for a system formed by layers where the refractive index of the structure is modulated by a Gaussian function. The system presents transparency bands of transmission and gaps without transmission. The escape frequencies are situated near these transparency bands but they do not coincide with them. is the frequency (mode) and Γ describes the width of the states. For these systems, the escape states are very wide. A non Gaussian system presents resonance peaks in the transmission and the escape states are narrow. The formation of transparency bands in the transmission for a Gaussian system is attributed to the widening of the escape states.

Photon and carrier management design for nonplanar thin-film copper indium gallium selenide photovoltaics

Nonplanar structured photovoltaic absorber design has potential to achieve high solar cell efficiency with significantly reduced material use. We report optoelectronic simulations that highlight photon and generated carrier management opportunities for improvement of thin film Cu(InxGa1−x)Se2 (CIGS) device performance. Structures realized via either self-assembly or patterning via nanoimprint lithography, and also a combination of both are predicted to exhibit significant increases in short circuit current density and open circuit voltage simultaneously. The structures investigated include: 1) self-assembled nonplanar structures that strongly scatter incident light and enhance carrier generation near regions of high electric potential, 2) lithographically-patterned embedded periodic dielectric structures, 3) planar dielectric layers that separate the CIGS absorber from the molybdenum back-contact via reduced-area contacts that minimize optical and electronic losses, 4) a combination of these for combined effects. We find that the self-assembled nonplanar CIGS cells with 700nm planar equivalent thickness, combined with dielectric separation layers yield increases in short circuit current density and open circuit voltage up to 3.4mAcm−2 and 29mV, respectively. The absolute efficiency increases from 15.4% to 18.1%, compared to the predicted efficiency for planar CIGS thin film cells of equivalent thickness. The addition of a single layer MgF2 anti-reflection coating brings the maximum predicted efficiency up to 19.7% for randomly textured devices.

Nonlinear coupled electromagnetic wave propagation: Saturable nonlinearities

Propagation of a sum of two monochromatic transverse electric (TE) waves in a plane dielectric layer filled with nonlinear medium is considered. Nonlinearity in the layer is described by a diagonal tensor with arbitrary functions w.r.t. squared module of the complex amplitudes of an electric field. We look for guided waves that propagate along the boundaries of the layer and decay when they move off from the boundaries. It is proved that a novel nonlinear propagation regime arises, called ‘coupled TE wave.’ It is shown that two TE waves–generating the coupled wave–propagate at different frequencies ω1, ω2 with different propagation constants γ1, γ2, respectively. The wave propagation problem is reduced to a nonlinear 2-parameter transmission eigenvalue problem for Maxwell’s equations. An original analytical method to study the problem is suggested. For a wide class of saturable nonlinearities, it is proved the existence of isolated coupled eigenvalues (that correspond to the coupled propagation modes) and intervals of its localisation are found, zeros of the eigenfunctions are also determined. Theoretical results are illustrated with numerical calculations.

Approximate analytical solution for waveguide excitation of a plane dielectric layer by a Gaussian beam at frustrated total internal reflection.

We present an approximate 2D asymptotic analytic theory of light field excitation in a plane thin dielectric layer under conditions of frustrated total internal reflection, when an inclined Gaussian beam, falling from a triangular prism, excites a decaying field in air spacing between a prism and a plane dielectric. Ignoring the radiation scattering on the sharp edges of a prism, we have obtained the formulas that allow us to compute spatial structures of an electromagnetic field in every point of space and to estimate the integral efficiency of waveguide mode excitation in a plane dielectric layer and the total energy of a reflected beam. It is shown that the width of an initial Gaussian beam has an effect on waveguide mode intensity.

Integral equations formulation of plasmonic transmission lines.

In this paper, a comprehensive integral equation formulation of plasmonic transmission lines is presented for the first time. Such lines are made up of a number of metallic strips with arbitrary shapes and dimensions immersed within a stack of planar dielectric or metallic layers. These lines support a number of propagating modes. Each mode has its own phase constant, attenuation constant, and field distribution. The presented integral equation formulation is solved using the Method of Moments (MoM). It provides all the propagation characteristics of the modes. The new formulation is applied to a number of plasmonic transmission lines, such as: single rectangular strip, horizontally coupled strips, vertically coupled strips, triangular strip, and circular strip. The numerical study is performed in the frequency (wavelength) range of 150-450 THz (0.66-2.0 μm). The results of the proposed technique are compared with those obtained using Lumerical mode solution, and CST. Very good agreement has been observed. The main advantage of the MoM is its intrinsic speed for this type of problem compared to general purpose solvers.

A rigorous theoretical model of guided waves excitation in a plane dielectric layer under electromagnetic diffraction by a conducting strip

An exact solution of two-dimensional problem of plane electromagnetic wave scattering by a perfectly conducting strip in the presence of a parallel plane dielectric layer is presented. The given solution is constructed using the mode-matching technique in the form of diffraction integrals over propagation parameter, i.e. in the form of superposition of a large number of homogeneous and inhomogeneous plane waves with continuous spectrum of spatial frequencies. These integrals have poles, which are caused by the presence of a transparent dielectric layer and correspond to its waveguide modes. Because of this, diffraction integrals need the procedure of regularization with explicit extraction of pole terms and smoothing of integrands, whereupon the residual diffraction integrals are computed using simple numerical methods. They describe usual scattered field of a bounded obstacle, which is determined by regularized diffraction integrals and decreases in all directions from an obstacle. Besides, the total diffraction field contains a discrete finite sum of waveguide fields of guided modes of a plane dielectric layer, which correspond to the extracted pole terms of initial diffraction integrals. These fields correspond to pairs of guided waves, which move apart from the region of their excitation near a strip, propagating parallel to the boundaries of a layer and conserving finite amplitude at infinity.

Back Cover Picture: Laser & Photon. Rev. 7(2)/2013

Laser & Photonics ReviewsVolume 7, Issue 2 Back CoverFree Access Back Cover Picture: Laser & Photon. Rev. 7(2)/2013 First published: 08 March 2013 https://doi.org/10.1002/lpor.201370021AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract Proof-of-concept nanolithography system is designed and demonstrated for producing a sub-wavelength interference pattern. The system employs the spatially-confined diffraction in a hyperbolic medium arranged of alternating planar metallic and dielectric layers. Volume plasmon polaritons excited with the top mask propagate across the metallic-dielectric interfaces along the characteristic planes inside the hyperbolic slab. Shown is the numerically simulated grating nanolithography pattern (Picture: S. Ishii et al. dx.doi.org/10.1002/lpor.201200095, pp. 265–271, in this issue) Volume7, Issue2March 2013 RelatedInformation

Detailed simulation of structural color generation inspired by the Morpho butterfly

The brilliancy and variety of structural colors found in nature has become a major scientific topic in recent years. Rapid-prototyping processes enable the fabrication of according structures, but the technical exploitation requires a profound understanding of structural features and material properties regarding the generation of reflected color. This paper presents an extensive simulation of the reflectance spectra of a simplified 2D Morpho butterfly wing model by utilizing the finite-difference time-domain method. The structural parameters are optimized for reflection in a given spectral range. A comparison to simpler models, such as a plane dielectric layer stack, provides an understanding of the origin of the reflection behavior. We find that the wavelength of the reflection maximum is mainly set by the lateral dimensions of the structures. Furthermore small variations of the vertical dimensions leave the spectral position of the reflectance wavelength unchanged, potentially reducing grating effects.

Dielectric permittivity simulations of layered composites with rough interfacial surfaces

Finite difference quasi-electrostatic simulations are used to predict the interfacial dielectric permittivity of a rough-surfaced contact zone between two distinct materials in a layered composite. Fractional Brownian surfaces, which have fractal geometry, are used to represent the rough interfaces in a model space. The interfacial simulations are combined with a macroscopic analytic model for planar dielectric layers, which allows the calculation of composite permittivity for a layered composite with an arbitrary ratio of surface roughness-to-layer thickness and arbitrary volumetric filling fractions of the constituents. Examples are given for a ceramic-polymer system, and the effects of alternate ratios of constituent dielectric permittivities and changes in surface fractal character are also explored. Compared to the behavior of composites with perfectly flat interfaces, the rough-surfaced composite exhibits a significantly earlier increase in permittivity as a function of the volumetric filling fraction of the higher permittivity material. The behavior with extremely rough surfaces tends towards the predictions of the effective medium approximation

Diffraction of a plane electromagnetic wave by a slot in a conducting screen with a transverse dielectric layer

The problem of diffraction of a plane electromagnetic wave by a slot in a planar perfectly conducting arbitrary thick screen with an infinite planar dielectric layer passing through the slot transversely to the screen is solved rigorously. In each of the field existence domains (two domains on either side of the screen and the interior of the slot), the solution is represented as an expansion in piecewise harmonic or exponential modes that allow for reflection and refraction at the boundaries of the dielectric layer. It is found that a set of functions describing such modes is complete enough to construct a solution satisfying all boundary conditions of the diffraction problem. The procedures of solution construction for the case at hand and for the same diffraction structure without the dielectric layer are compared.