Tatjana Gric

Vilnius Gediminas Technical University · Department of Electronic Systems

A nanostructured metamaterial absorber composed of alternating semiconductor and dielectric layers is presented and numerically analyzed in this article. The development of a semiconductor adjustable absorber in the THz will open up new possibilities for quantum information science, imaging, health, and sensing applications, particularly those that...

The development of a semiconductor adjustable absorber in the THz will open up new possibilities for quantum information science, imaging, health, and sensing applications, particularly those that need to be portable. Here, we build a unique semiconductor nanowire metamaterial that exhibit increased absorption efficiency at various temperatures by...

It is generally known for metal nanoparticles and metal surfaces that surface plasmons, or the quanta of the collective oscillations of free electrons at a metal surface, are readily tunable, but less is known about semiconductor nanowires. Here, we find that surface plasmons on semiconductor nanowires have a very significant tunability that can be...

Nanowire metamaterials play a pivotal role in a wide variety of applications including antennas research field and cancer detection in clinical practice. In the following we make a step forward by investigating properties of surface waves at the boundary of ellipsoidal nanowire metamaterial, specifically, we study effective properties of the ellips...

Lately, the negative absorption in plasma-dielectric nanostructures provided a fertile ground for the advancement of THz electronic appliances. Herein we present a plasma-dielectric nanostructure aiming to achieve enhanced negative absorption in the high frequency region resulting because of strong plasma-light interaction. The paper presents dispe...

The $\mathbb R$-linear boundary value problem in a multiply connected domain on a flat torus is considered. This problem is closely related to the Riemann-Hilbert problem on analytic functions. The considered problem arises in the homogenization procedure of random media with complex constants which express the permittivity of components. A new asy...

Tunable metamaterials belonging to the class of different reconfigurable optical devices have proved to be an excellent candidate for dynamic and efficient light control. However, due to the consistent optical response of metals, there are some limitations aiming to directly engineer electromagnetic resonances of widespread metal-based composites....

Herein, we deal with the propagation of surface plasmon polaritons at the interface of metal-free metamaterial with anisotropic inclusions. The anisotropy effect of conventional and well-known nanostructured metamaterial combined of alternating layers is enhanced by employing anisotropic semiconductor sheets into the structure. The former provides...

To the best of our knowledge topological change of the iso-frequency surface of hyperbolic metamaterials paves the way for the unique capabilities aiming to engineer propagation of the wave. Herein, an enhanced semiconductor-based hyperprism structure is presented aiming to seek for the optical switching and beam steering dependencies. Based on the...

In this study, the models for the DNA origami lattice will be investigated. Our aim is to theoretically explore the ways of constructing DNA origami. To achieve this goal the DNA origami structure, consisting of nanowires embedded in a host material, will be treated from the perspective of nanowire metamaterial. Surface plasmon polaritons propagati...

Acoustic metamaterials are introduced as the structures with the alternating elements possessing effective properties that can be tuned seeking for the dramatic control on wave propagation. Homogenization of the structure under consideration is needed aiming to calculate permittivity of metamaterial. We present theoretical outcomes studying an acou...

As a novel type of artificial media created recently, metamaterials demonstrate novel performance and consequently pave the way for potential applications in the area of functional engineering in comparison to the conventional substances. Acoustic metamaterials and plasmonic structures possess a wide variety of exceptional physical features. These...

Surface plasmon polaritons (SPPs) propagating at the interfaces of composite media possess a number of fascinating properties not emerging in case of conventional SPPs, i.e., at metal-dielectric boundaries. We propose here a helpful algorithm giving rise for investigation of basic features of complex conductivity dependent SPPs at the interface sep...

Light-matter interactions in a material may be dramatically influenced by the features of the medium. Moreover, the electromagnetic characteristics of the material in the nearby areas may make a dramatic impact as well. Following the first scenario, the medium is considered to be local, whereas in the other case, it is nonlocal. It has been demonst...

The main features of surface plasmon polaritons (SPPs) that can propagate in a metamaterial–magnetic plasma structure are studied from theoretical perspectives. Both the conventional and imaginary parts of the dispersion relation of SPPs are demonstrated considering transverse magnetic (TM) polarization. We examine and discuss the influence of the...

Herein, we develop an enhanced and automated methodology for detection of the tumour cells in fixed biopsy samples. Metamaterial formalism (MMF) approach allowing recognition of tumour areas in tissue samples is enhanced by providing an advanced technique to digitize mouse biopsy images. Thus, a colour-based segmentation technique based on the K-me...

A semiconductor-based hyperprism structure is presented aiming to seek for the optical switching and beam steering functions. Engineering the doping level of the semiconductor, the beam steering system reaches an adjustable angle of 1.4 rad.

Graphene paves the way for the outstanding applications as it is one-atom thick and possesses perfect tunability properties. The main goal of this work is to study mode patterns of surface waves propagating in the graphene-based structures in the far-infrared region. Herein, we study a broad variety of graphene structures starting with the simplest...

The dependence of the Purcell factor on nanowire metamaterial geometry was analyzed. Calculations made about the Purcell factor in realistic composites, operating at an optical spectral range, are provided. We applied a metamaterial, aiming to mitigate the negative effects of absorption in metals on the Purcell effect in nanowire structures. A nano...

Early detection of a tumor makes it more probable that the patient will, finally, beat cancer and recover. The main goal of broadly defined cancer diagnostics is to determine whether a patient has a tumor, where it is located, and its histological type and severity. The major characteristic of the cancer affected tissue is the presence of the gliom...

The tunable spiral nanowire metamaterial design at optical frequency is presented, and the surface polaritons are theoretically studied. It was found that the dispersions of the polaritons could be tuned by varying physical dimensions of the spiral nanowire metamaterial. This geometry is unique. Doing so, one may dynamically control the properties...

Here we present a short review of the theoretical description of graphene-based hyperbolic metamaterials with nonlocal quantum gain. The exact in RPA, nonlocal graphene conductivity model is used to describe the behavior of infinite and finite graphene–dielectric stacks with various input parameters, such as dielectric properties, graphene doping a...

We numerically investigate terahertz photoconductive antenna based on optimized plasmonic nanostructures, stressing the stronger enhancement in case of transparent conducting oxide nanowires. The case is treated by means of local and nonlocal effective medium approximations.

We present studies on the effective properties of mice biological tissues samples treating them as disordered metamaterial media aiming to identify cancerous areas in the mice brain tissue biopsies.

We investigate the propagation of surface plasmon polaritons (SPPs) at the boundary of metamaterial and topolological insulators. Instance of Bi2Se3 and metamaterial boundaries is investigated. The topological insulators under consideration are three dimensional topological insulators of the second generation. Dispersion relations, absorption chara...

Herein we study theoretically surface plasmon polariton (SPP) wave propagation along the nanostructured graphene-based metamaterial/corrugated metal interface. We apply the effective medium approximation formalism aiming to physically model nanostructured metamaterial. The transfer matrix approach is applied to compute the dispersion relationship f...

The extensive research of layered materials has revealed that it is possible to obtain a new degree of freedom for tuning the dispersion properties. Based on this concept, researchers have investigated the hyperbolic metamaterials. Recently, several kinds of photonic crystals have been proposed as classical counterparts of the layered materials. Ho...

We investigate the propagation of surface plasmon polaritons (SPPs) at the boundary of metamaterial and topological insulators. Instances of Bi2Se3, Bi2Te3 and metamaterial boundaries are investigated. The topological insulators under consideration are three dimensional topological insulators of the second generation. Dispersion relations, absorpti...

Photoexcited graphene can behave as the gain medium aiming to come up with the coherent radiation at low THz spectral region. However, its response is very weak because of its atomic dimensions. Herein, a different design aiming to obtain effective tunable THz amplifiers, having small dimensions and lasers with broadband operation based on active T...

Here, I report on a highly nonlocal metamaterial formed by means of a plasmonic nanorod composite. An analytical characterization of the nonlocal optical response of plasmonic nanowire metamaterials is presented. The former enables negative refraction, subwavelength light guiding, and emission lifetime engineering. I analyze the dispersion of optic...

This chapter contains sections titled: Introduction Types of Metamaterials Examples of the Disordered Metamaterials Conclusions and Outlook

In this paper, we show the approach to enhance the optical properties of the plasmonic nanowires from the perspectives of both field enhancement and tunability. Two different cases have been suggested for the consideration: the first one uses hollow-core metamaterial interface, while the other involves metallic nanowire metamaterial interface. It h...

A novel metamaterial (MM) to guide surface plasmon polariton (SPP) is considered. Specific example of three-layered nanostructured MM and its dispersion engineering are studied in details allowing the development of new devices. Herein we deal with the general original concept of MMs based on inclusions of the additional layers as with a promising...

We propose and implement a new concept for three-layered transparent conducting oxides (TCO) based nanostructured metamaterial. It is based on alternating AZO, GZO and PbS layers. In particular, we propose a novel metamaterial for surface plasmon polariton guiding. Specific example of AZO/GZO/PbS metamaterial and its dispersion engineering are stud...

Herein, we discover the new kinds of surface wave on nanostructured metamaterial (MM), crossing the light line with a substantial portion at lower frequencies lying above the free space light line. Interestingly, the propagation of such surface waves is found to be sensitive to the parameters of the materials employed in nanostructures. Furthermore...

Herein, we numerically investigate terahertz photoconductive antennas (PCAs) based on optimized plasmonic nanostructures and absorption enhancement in nanocylinders. Plasmonic behavior in the visible to near-infrared light spectrum is achievable due to the metallic nanostructure employment. Herein, we study the absorption enhancement of silver and...

Composites designed by employing metal/dielectric composites coupled to the components of the incident electromagnetic (EM) fields are named metamaterials (MMs), and they display features not observed in nature. This type of artificial media has attracted great interest, resulting in groundbreaking theory that bridges the gap between EM and photoni...

Here, new kinds of surface waves on nanostructured metamaterial (MM), crossing the light line with a substantial portion at lower frequencies lying above the free space light line, are considered. We present the numerical study of dispersion features of hyperbolic MMs for various cases, and the tunability of hyperbolic MMs based on grapheme-dielect...

The analytical analysis of the metamaterial boundary with the rotational disorder reveals both bound and leaky surface plasmon (SP) modes. The dispersion relations of SPs propagating on a surface of these metamaterials are presented along with the propagation lengths. The rigorous modeling and analysis of surface waves at the boundary of two metama...

A novel metamaterial (MM) to guide surface plasmon polariton (SPP) is considered. Specific example of three-layered nanostructured MM and its dispersion engineering are studied in details allowing the development of new devices. The metal material stands for as the limiting factor of the frequency range that SPP mode exists. The SPP mode at high fr...

Nanobeam composites are important for designing sensing, nonlinear, and emission functionalities. Here, we describe a method for tuning the plasmonic properties of a silver nanobeam-based metamaterial. Such metamaterials open the wide avenues for a variety of applications in the fields of bio- and chemical sensing, nonlinearity enhancement, and flu...

Considering the losses of metal and semiconductor and by obtaining exact dispersion relations of the modes, we theoretically study the propagation characteristics of surface plasmons supported by disordered nanowire metamaterials. The metamaterials are composed of disordered nanowires made of metal or semiconductor embedded into the dielectric mate...

Diversiform hybrid-polarization surface plasmon polaritons (HSPPs) at metamaterial (MM)–dielectric interfaces have initially been predicted by theoretical considerations based on dispersion equations. Here, we discuss hybrid HSPPs at the interface between (1) transparent conducting oxide (TCO)/dielectric MMs and TCO or (2) MMs and dielectrics throu...

We discover a new kind of surface wave on semiconductor nanostructured metamaterial, which crosses the light line with a substantial portion at lower frequencies lying above the free space light line. Interestingly, the propagation of such surface wave is found to be sensitive to the parameters of the semiconductor. Furthermore, the Ferrel-Berreman...

As reported by Ritchie, the fundamental optical excitations that are confined to a metal/dielectric interface are referred as the surface plasmon polaritons. In the present study, we report on a theoretical investigation of the dispersion relation of surface plasmon polaritons on the periodically corrugated surfaces. Tunability of these structures...

The properties of surface-plasmon-polaritons (SPPs) at the interface of two nanowire metamaterials are investigated theoretically. Calculated dispersion relations and propagation lengths are presented. It is demonstrated that the SPPs can be tuned by controlling the metamaterial design. Tunability of these structures can be enhanced further by incr...

Despite the fact that metal is the most common conducting constituent element in the fabrication of metamaterials, one of the advantages of graphene over metal is that its conductivity can be controlled by the Fermi energy. Here, we theoretically investigate multilayer structures comprising alternating graphene and dielectric layers as a class of h...

Herein, we present a detailed analysis of the propagation of surface waves along spoof-insulator-spoof (SIS) waveguides. Analytical dispersion equations are derived for the geometry under investigation, in view of the presence of the semiconductor and transparent conducting oxide (TCO) corrugations. More importantly, the proposed formulation reveal...

We consider the surface plasma polariton dispersion in inhomogeneous semiconductor/air interface. The plasma permittivity in a two-layer compound is studied by inclusion of an inhomogeneous plasma density. Numerical solutions were obtained for the plasma dispersion curve of an inhomogeneous semiconductor/dielectric structure. A detailed analysis wa...

We provide an analysis of surface-wave propagation at a boundary between a semiconductor and a multilayered hyperbolic metamaterial. In particular we analyzed the structure dispersion for various cases of a hyperbolic metamaterial. It is concluded that one can tune the frequency range of surface waves by varying the thickness of dielectric sheets....

Nowadays, there is a need to search for better materials aimed for plasmonic and metamaterial applications. Transparent conducting oxides (TCOs) are known as low-loss plasmonic materials in the near-infrared wavelength range. The further design of the lower loss materials would be available by fulfilling a more sophisticated theoretical study. In t...

Herein we present an approach on expansion of the work by Pendry, who put forward the idea of spoof surface plasmons in conducting films as a way to engineer surface plasmon polaritons (SPPs) dispersion curves. Investigating a conducting film with holes filled with a metamaterial, we find that the surface texture and geometry can significantly infl...

We have investigated the properties of structures incorporating graded index materials with parabolic permittivity profile. Surface-plasmon-polaritons at the interface of graded index material and semiconductor are studied by means of numerical simulations. We analyze the dependence of the dispersion characteristics on the graded index material pro...

The rigorous modeling and analysis of surface waves at the boundary of two metamaterials are presented. The nature of the phenomenon of the surface-plasmon-polaritons and the influence of various parameters on it are investigated. We have analyzed the properties of structures incorporating nanostructured metamaterials. Surface-plasmon-polaritons at...

We report on a theoretical investigation of the dispersion relation of surface plasmon polaritons (SPPs) on a periodically corrugated semiconductor surface. We assumed Drudes permittivity model of the semiconductor, which accurately describes the loss of these spoof SPPs. In the THz frequency range, the properties of the dispersion and loss of spoo...

We present a novel theoretical approach for analytically solving wave propagation through two-dimensional (2D) inhomogeneous slab waveguides. The validity and reliability of our analytical approach is verified by its application to electrical field distribution in 2D waveguides, when compared with numerically exact solution. The main advantage of t...

A novel analytic solution to field distribution is used to calculate the intensity distribution for channel waveguides with a two-dimensional diffusion-type refractive index profile. Composition profiles for the waveguides are obtained by applying the two-dimensional diffusion theory to treat the case of isotropic sideways diffusion. The dependence...

Optical waveguides have been a subject of an intensive theoretical research, resulting in applications in several fields, and stimulated research in integrated optics. Homogeneous dielectric waveguides and their properties are covered in detail in many articles and textbooks. However, in waveguides loaded with arbitrary inhomogeneous dielectrics, a...

Spoof plasmons are bound electromagnetic waves (EM) at frequencies outside the plasmonic range mimicking ("spoofing") surface plasmons (SPs), which propagate on periodically corrugated metal surfaces. In recent years, electromagnetic waves propagating at an interface between a metal and dielectric have been of significant interest. Although most pl...

A new general expression of a solution to Maxwell׳s equations derived recently has been applied to a 1-D inhomogeneous medium. It is shown that it solves any inhomogeneous refractive index profile. Its main advantage is that it does not require integration of either the differential wave equation or the refractive index profile, as it is the case w...

Here we present the analyses of the open (without a metal screen) ridged and photonic waveguide structures by means of the electrodynamical rigorous method of the Singular Integral Equations (SIE). The waveguides are made of a lossy silicon carbide (SiC) material. We have discovered peculiarities of the dispersion characteristics. We have found the...

Here we present the dependences of the phase and attenuation constants of silicon carbide (SiC) cylindrical rod waveguide upon frequency at different temperatures, i.e. T = 1800 degrees C and T = 1900 degrees C when the rod radius is relatively large. We have also calculated the electric and magnetic field distributions at different frequencies in...

Here we for the first time present the dependencies of the dispersion characteristics of the main mode propagating in a lossy cylindrical waveguide on its radius. The waveguide is made of absorbing microwave silicon carbide (SiC) material. The dispersion characteristics of ceramic SiC waveguide were investigated by the partial area method. The comp...

Presented the electro dynamical analysis of the n -Si photonic waveguide structures. The rigorous solution of the problem was fulfilled by the Singular Integral Equations' method (SIE) using the Muller's method. Here the dispersion characteristics of six different structures with three, five and seven air holes are analyzed. The air holes are locat...

Here we present the 3D vector electric field distributions of the main and the first higher modes propagating in the open metamaterial rod and hollow-core waveguides.

Here we present the 3D vector magnetic field distributions of the main mode and the first higher modes propagating in lossy SiC rod waveguides at different temperatures and the dispersion characteristics of the SiC rectangular and circular rod waveguides.

We present here the solution of the eigenvalue problems for the open metamaterial square and circular rod waveguides. The Maxwell's equations for the electrodynamical analysis of the open waveguides were solved by the Singular Integral Equations' (SIE) method and partial area method. Our SIE method is pretty universal and let us rigorously analyze...

Semiconductor rod waveguides are widely used in the large variety of devices. Scientists and engineers have been investigating circular cylindrical waveguides for many years due to their excellent electrodynamical characteristics (e.g. a large broad bandwidth) and the wide possibilities for their implementation in microwave and optoelectronic devic...

Here we present the electrodynamical analysis of the ceramic circular rod silicon carbide (SiC) waveguide with the radius R = 2.5 mm at the temperature 1800° C. We present dispersion characteristics of the SiC waveguide in the frequency range 1?100GHz. We show the losses of two slow and one fast waveguide modes. We give here the electric field dist...

Here are presented the results of an electrodynamical analysis of the SiC waveguides with two different radii R = 1.5 mm and R = 2.5 mm. We have investigated the dispersion characteristics of these waveguides as well as the electric field distributions in the waveguide cross-sections at f = 50 and 25 GHz.