## About

68

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Introduction

Theorist experienced in optics, photonics and light-matter interactions. Current interests span energy harvesting, infrared microspectroscopy, plasmonics, optics in biology, and fundamental aspects of light scattering from particles.

Additional affiliations

October 2022 - August 2023

July 2021 - October 2022

July 2018 - July 2021

Education

September 2011 - June 2015

September 2009 - May 2011

September 2005 - May 2009

## Publications

Publications (68)

Metal halide perovskite materials have been extensively explored in modern photonic devices. Photonic crystals (PCs) are periodic structures with specific optical properties, such as photonic stop bands and “slow photon” effects, which can tailor the propagation and distribution of photons in photoelectric devices. PCs have in recent years been wid...

Nano- and microparticles are popular media to enhance optical signals, including fluorescence from a dye proximal to the particle. Here we show that homogeneous, lossless, all-dielectric spheres with diameters in the mesoscale range, between nano- (≲100 nm) and micro- (≳1 μm) scales, can offer surprisingly large fluorescence enhancements, up to F∼1...

A thorough analysis of the emission via the magnetic dipole (MD) transition, called magnetic light below, of trivalent rare-earth ions in or near dielectric homogeneous spheres has been performed. In the search for enhancement of fluorescence from magnetic light, one faces the difficult task of identifying the regions where the combined fluorescenc...

Photonic devices are cutting-edge optical materials that produce narrow, intense beams of light, but their synthesis typically requires toxic, complex methodology. Here we employ a synthetic biology approach to produce environmentally-friendly, living microlenses with tunable structural properties. We engineered Escherichia coli bacteria to display...

In an absorbing or an active host medium characterized by a complex refractive index ${n_2} = n_2^\prime + {\rm i}n_2^{{\prime \prime}}$ n 2 = n 2 ′ + i n 2 ′ ′ , our previously developed modified dipole long-wave approximation (MLWA) is shown to essentially overlie with the exact Mie theory results for localized surface plasmon resonance of spheri...

In an absorbing or an active host medium characterized by a complex refractive index $n_2=n_2'+{\rm i}n_2''$, our previously developed modified dipole long-wave approximation (MLWA) is shown to essentially overly with the exact Mie theory results for spherical nanoparticle with radius $a\lesssim 25$ nm ($a\lesssim 20$ nm) in the case of Ag and Au (...

An experimental demonstration of directivities exceeding the fundamental Kildal limit, a phenomenon called superdirectivity, is provided for spherical high-index dielectric antennas with an electric dipole excitation. A directivity factor of about 10 with a total efficiency of more than 80% for an antenna having a size of a third of the wavelength...

Metal nanoparticles have traditionally been used to enhance optical signals, including fluorescence from a dye proximal to the particle. Here, we sought to examine whether appreciable enhancement was possible using relatively simple all-dielectric particles. Using rapid numerical simulations, we deduce that lossless all-dielectric spherical particl...

We discover regimes for promoting decay rates of magnetic light due to magnetic dipole (MD) transitions of trivalent rare earth ions located inside or near dielectric homogeneous spheres by as much as three orders of magnitude. A number of configurations involving sphere parameters and a rare earth emitter radial position are determined at which th...

An experimental demonstration of directivities exceeding the fundamental Kildal limit, a phenomenon called superdirectivity, is provided for spherical high-index dielectric antennas with an electric dipole excitation. A directivity factor of about 10 with a total efficiency of more than 80% for an antenna having a size of a third of the wavelength...

We suggest a strategy for designing regular 2D arrays of nanoholes (NHs) in metal films with far-field scattering properties similar to that of regular 2D arrays of nanodisks (NDs) with the same periodicity. Full-wave simulations for perfectly conducting, Ag and Au NDs and respectively designed arrays of NHs demonstrate a minor difference between f...

A novel concept of a \textit{mesocavity}, based on a simple yet counter-intuitive idea of covering metal nanoparticles with unusually thick ($\gtrsim 100$ nm) high-index dielectric shells, is demonstrated in technologically relevant and largely sought-after case of an upconversion (UC) enhancement. For readily available combinations of materials an...

A suitability of a nanostructure for a metal-enhanced fluorescence (MEF) is usually assessed from the value of the maximal fluorescence enhancement factor, F, which it can generate. However, F is an ambiguous quantity which may dramatically depend on the intrinsic quantum yield, q0, of the emitter in a free space. Here, we suggest F = Fq0 =1 taken...

Electrically small dielectric antennas are of great interest for modern technologies, since they can significantly reduce the physical size of electronic devices for processing and transmitting information. We investigate the influence of the resonance conditions of an electrically small dielectric spherical antenna with a high refractive index on...

Small form-factor, narrow band, and highly directive antennas are of critical importance in a variety of applications spanning wireless communications, remote sensing, Raman spectroscopy, and single photon emission enhancement. Surprisingly, we show that the classical directivity limit can be appreciably surpassed for electrically small multilayer...

A suitability of a nanostructure for a metal-enhanced fluorescence (MEF) is usually assessed from the value of the maximal fluorescence enhancement factor, $\mathcal{F}$, which it can generate. However, $\mathcal{F}$ is an ambiguous quantity which may dramatically depend on the intrinsic quantum yield, $q_0$, of the emitter in a free space. Here we...

The Foldy-Lax equation is generalized for a medium that consists of particles with both electric and magnetic responses. The result is used to compute fields scattered from ensembles of particles. The computational complexity is reduced by hierarchical clustering techniques to enable simulations with on the order of 10^10 particles. With so many pa...

Surface lattice resonances (SLRs) emerging in regular arrays of plasmonic nanoparticles (NPs) are known to be exceptionally sensitive to the homogeneity of the environment. It is considered necessary to have a homogeneous environment for engineering narrowband SLRs, while in a half-space environment, SLRs rapidly vanish as the contrast between the...

Electrically small dielectric antennas are of great interest for modern technologies, since they can significantly reduce the physical size of electronic devices for processing and transmitting information. We investigate the influence of the resonance conditions of an electrically small dielectric spherical antenna with a high refractive index on...

Collective lattice resonances in regular arrays of plasmonic nanoparticles have attracted much attention due to a large number of applications in optics and photonics. Most of the research in this field is concentrated on the electric dipolar lattice resonances, leaving higher-order multipolar lattice resonances in plasmonic nanostructures relative...

Contrary to a paradigm of metal-enhanced fluorescence, unusually thick dielectric coatings can be very favorable to achieve extreme values of averaged fluorescence enhancement factor $\bar F\gtrsim 3000$ for emitters located on the surface, or in the interior, of the shell of Au@dielectric spherical core-shell particles under realistic conditions,...

In the era of Internet of things, the emerging technologies require new generation of small form-factor, narrowband, and highly directive antennas to reduce the interference of radio-frequency waves. Here, on using a stochastic optimization algorithm combined with a rigorous analytic solution, we show that the classical directivity limit can be app...

The modified long-wavelength approximation (MLWA), a next order approximation beyond the Rayleigh limit, has been applied usually only to the dipole l=1 contribution and for the range of size parameters x not exceeding x≲1 to estimate far- and near-field electromagnetic properties of plasmonic nanoparticles. Provided that the MLWA functional form f...

Engineering nanostructures with exceptionally high-Q resonances mediated by the Fano-type hy-bridization between discrete states associated with the periodicity of the structure and broadband resonances excited on constituent scatterers is the emerging field in optics and photonics. These collective lattice resonances (CLRs) attracted a lot of atte...

Mostly forsaken, but revived after the emergence of all-dielectric nanophotonics, the Kerker effect can be observed in a variety of nanostructures from high-index constituents with strong electric and magnetic Mie resonances. A necessary requirement for the existence of a magnetic response limits the use of generally nonmagnetic conventional plasmo...

We show that in metal-dielectric core-shell nanoparticles, unusually thick dielectric coatings produce extreme fluorescence enhancement with enhancement factor F ¯ ≳ 3000 for emitters located near Au@dielectric spherical particles under realistic conditions.

The modified long-wavelength approximation (MLWA), a next order approximation beyond the Rayleigh limit, has been applied usually only to the dipole $\ell=1$ contribution and for the range of size parameters $x$ not exceeding $x\lesssim 1$ to estimate far- and near-field electromagnetic properties of plasmonic nanoparticles. Provided that the MLWA...

A reexamination of the Clausius-Mossotti relation in which material with both electric and magnetic responses yields surprising results. Materials with indices near zero and with real parts less than zero, that is the real part of both the permeability and permittivity are negative, are found to emerge from the interaction of electric and magnetic...

The Foldy-Lax equation is generalized for a medium which consists of particles with both electric and magnetic responses. The result is used to compute fields scattered from ensembles of particles. The computational complexity is reduced by hierarchical clustering techniques to enable simulations with on the order of 10^10 particles. With so many p...

We present a computer code for calculating near- and far-field electromagnetic properties of multilayered spheres. STRATIFY is a one-of-a-kind open-source package that allows for efficient calculation of electromagnetic near-field, energy density, total electromagnetic energy, and radiative and non-radiative decay rates of a dipole emitter located...

Mostly forsaken, but revived after the emergence of all-dielectric nanophotonics, the Kerker effect can be observed in a variety of nanostructures from high-index constituents with strong electric and magnetic Mie resonances. Necessary requirement for the existence of a magnetic response prohibits the use of generally non-magnetic conventional plas...

A potential control over the position of maxima of scattering and absorption cross sections can be exploited to better tailor nanoparticles for specific light–matter interaction applications. Here we explain in detail the mechanism of an appreciable blue shift of the absorption cross-section peak relative to a metal spherical particle localized sur...

Lecture from METANANO Summer School on Nanophotonics and Metamaterials

We present a computer code for calculating near- and far-field electromagnetic properties of multilayered spheres. STRATIFY is one-of-a-kind open-source package which allows for the efficient calculation of electromagnetic near-field, energy density, total electromagnetic energy, radiative and non-radiative decay rates of a dipole emitter located i...

Using the extended discrete interaction model and Mie theory, we investigate the tunability of the optical polarizability of small metallic nano-bubbles. We show that the spectral positions of symmetric and antisymmetric dipolar plasmon resonances vary with the ratio of particle radius to hole radius in a manner similar to one predicted for uniform...

Large scale simulations are performed by means of the transfer-matrix method to reveal optimal conditions for metal-dielectric core-shell particles to induce the largest fluorescence on their surfaces. With commonly used plasmonic cores (Au and Ag) and dielectric shells (SiO2, Al2O3, ZnO), optimal core and shell radii are determined to reach maximu...

A potential control over the position of maxima of scattering and absorption cross-sections can be exploited to better tailor nanoparticles for specific light-matter interaction applications. Here we explain in detail the mechanism of an appreciable blue shift of the absorption cross-section peak relative to a metal spherical particle localized sur...

Collective lattice resonances (CLRs) emerging under oblique incidence in 2D finite-size arrays of Si nanospheres have been studied with the coupled dipole model. We show that hybridization between the Mie resonances localized on a single nanoparticle and angle-dependent grating Wood-Rayleigh anomalies allows for the efficient tuning of CLRs across...

Large scale simulations are performed by means of the transfer-matrix method to reveal optimal conditions for metal-dielectric core-shell particles to induce the largest fluorescence on their surfaces. With commonly used plasmonic cores (Au and Ag) and dielectric shells (SiO2 , Al2O3 , ZnO), optimal core and shell radii are determined to reach maxi...

We present the theoretical model to predict the spectral position of Rayleigh anomalies emerged in hybrid system consisting of periodic array of plasmonic nanodisks embeded into the middle of defect layer of 1D photonic crystal (PhC). The spectral positions of these new emerged Rayleigh anomalies agree well with the results of exact simulations wit...

The interaction of non-monochromatic radiation with arrays comprising plasmonic and dielectric nanoparticles has been studied using the finite-difference time-domain electrodynamics method. It is shown that LiNbO3, TiO2, GaAs, Si, and Ge all-dielectric nanoparticle arrays can provide a complete selective reflection of an incident plane wave within...

Collective lattice resonances (CLRs) in finite-sized $ 2D $ 2 D arrays of dielectric nanospheres have been studied via the coupled dipole approximation. We show that even for sufficiently large arrays, up to $ 100 \times 100 $ 100 × 100 nanoparticles (NPs), electric or magnetic dipole CLRs may differ significantly from the ones calculated for infin...

We obtain exact analytic expressions for (i) the electromagnetic energy radial density within and outside a multilayered sphere and (ii) the total electromagnetic energy stored within its core and each of its shells. Explicit expressions for the special cases of lossless core and shell are also provided. The general solution is based on the compact...

New type of highly absorbing core-shell AZO/Au (aluminum doped zinc oxide/gold) and GZO/Au (gallium doped zinc oxide/gold) nanoparticles have been proposed for hyperthermia of malignant cells purposes. Comparative studies of pulsed laser hyperthermia were performed for Au nanoshells with AZO core and traditional SiO2 (quartz) core. We show that und...

The interaction of non-monochromatic radiation with two types of arrays comprising both plasmonic and dielectric nanoparticles has been studied in detail. We have shown that dielectric nanoparticle arrays provide a complete selective reflection of an incident plane wave within a narrow spectral line of collective lattice resonance with a Q-factor o...

Optical scattering corrections are invoked to computationally distinguish between scattering and absorption contributions to recorded data in infrared (IR) microscopy, with a goal to obtain an absorption spectrum that is relatively free of the effects of sample morphology. Here, we present a modification of the extended multiplicative signal correc...

We obtain exact analytic expressions for (i) the electromagnetic energy radial density within and outside a multilayered sphere and (ii) the total electromagnetic energy stored within its core and each of its shells. Explicit expressions for the special cases of lossless core and shell are also provided. The general solution is based on compact rec...

Collective lattice resonances in disordered 2 D arrays of spherical Si nanoparticles (NPs) have been thoroughly studied within the framework of the coupled dipole approximation. Three types of defects have been analyzed: positional disorder, size disorder, and quasi-random disorder. We show that the positional disorder strongly suppresses either th...

We analytically and numerically study coupling mechanisms between 1D photonic crystal (PhC) and 2D array of plasmonic nanoparticles (NPs) embedded in its defect layer. We introduce general formalism to explain and predict the emergence of PhC-mediated Wood-Rayleigh anomalies, which spectral positions agree well with the results of exact simulations...

Photon upconversion (UC) is the sequential absorption of two or more low frequency photons and subsequent emission of light at a higher frequency. Because of a large number of potential applications of this anti-Stokes process, extensive studies of UC have taken place in the last decades. The most crucial challenge in this field is the development...

We propose to utilize titanium nitride (TiN) as an alternative material for linear periodic chains (LPCs) of nanoparticles (NPs) which support surface plasmon polariton (SPP) propagation. Dispersion and transmission properties of LPCs have been examined within the framework of dipole approximation for NPs with various shapes: spheres, prolate and o...

We show that periodic structures from refractory titanium nitride (TiN) nanodiscs can support high-Q surface lattice resonances at telecom wavelengths. The obtained data open new prospects for utilization of TiN nanoparticles in next generation of photonics interconnects operating at high temperatures.

Regular arrays of plasmonic nanoparticles have brought significant attention over the last decade due to their ability to support localized surface plasmons (LSPs) and exhibit diffractive grating behavior simultaneously. For a specific set of parameters (i.e., period, particle shape, size, and material), it is possible to generate super-narrow surf...

Understanding the infrared (IR) spectral response of materials as a function of their morphology is not only of fundamental importance but also of contemporary practical need in the analysis of biological and synthetic materials. While significant work has recently been reported in understanding the spectra of particles with well-defined geometries...

This publisher’s note amends the author list of [Opt. Mater. Express 7, 5555 (2017)].

We have studied light induced processes in nanocolloids and composite materials containing ordered and disordered aggregates of plasmonic nanoparticles accompanied by their strong heating. A universal comprehensive physical model that combines mechanical, electrodynamical, and thermal interactions at nanoscale has been developed as a tool for inves...

We have studied thermal effects occurring during excitation of optical plasmonic waveguide (OPW) in the form of linear chain of spherical Ag nanoparticles by pulsed laser radiation. It was shown that heating and subsequent melting of the first irradiated particle in a chain can significantly deteriorate the transmission efficiency of OPW that is th...

In this paper a new set of plasmonic nanostructures operating at the conditions of an ideal absorption was proposed for novel biomedical applications. We consider spherical x/Au nanoshells and Au/x/Au nanomatryoshkas, where 'x' changes from conventional Si and SiO_2 to alternative plasmonic materials, such as zinc oxide doped with aluminum, gallium...

We have studied numerically the propagation of surface plasmon polaritons (SPPs) in linear periodic chains of plasmonic nanoparticles of different shapes. The chains are deposited on top of a thick dielectric substrate. While in many commonly considered cases the substrate tends to suppress the SPP propagation, we have found that this adverse effec...

We study numerically the discrete dispersion relations and waveguiding properties of relatively short linear chains of spherical and spheroidal silver nanoparticles. Simulations are based on the Drude model for the dielectric permittivity of metal and on the dipole approximation for the electromagnetic interaction of particles. We also simulate the...

We investigate numerically the propagation of steady-state monochromatic surface plasmon polaritons (SPPs) in curved chains of metal nanoparticles of various spheroidal shapes. We discuss the SPP propagation (decay of the amplitude), the polarization conversion due to coupling of orthogonally polarized SPPs, and the electromagnetic field localizati...

We consider propagation of surface plasmon polaritons in linear chains of equidistant metallic nanospheroids. We show that, for suitably chosen parameters, the propagation is free of spatial decay in spite of the full account of absorptive losses in the metal.

We study the spectral and transmission properties of optical waveguides in the form of different chain configurations of spherical Ag nanoparticles that can be synthesized under conditions of selective deposition on a dielectric substrate from a nanocolloid.