## About

60

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Introduction

**Skills and Expertise**

Additional affiliations

October 2010 - October 2012

## Publications

Publications (60)

We study theoretically and numerically high density of states for hyperbolic metamaterials (HMM). By the method of Green function we found a van Hove type singularity in the photonic energy density response of HMM with saddle point localization on photonic Fermi surface of metamaterial which can be related to the Lifshitz type optical topology tran...

We study theoretically and numerically spasing conditions and optical dynamics of a composite hyperbolic metamaterial interacting with gain molecules. By combining Maxwell-Bloch equations with Green's function approach, we calculate lasing frequency and threshold population inversion for various gain density in the gain layer. We demonstrate high l...

We study numerically the effect of mode mixing and direct dipole-dipole interactions between gain molecules on spasing in a small composite nanoparticles with a metallic core and a dye-doped dielectric shell. By combining Maxwell-Bloch equations with Green's function formalism, we calculate lasing frequency and threshold population inversion for va...

submitted to Physical Review B

We study cooperative effects in energy transfer (ET) from an ensemble of donors to an acceptor near a plasmonic nanostructure. We demonstrate that, in the cooperative regime, ET takes place from plasmonic superradiant and subradiant states rather than from individual donors leading to a significant increase in ET efficiency. The cooperative amplifi...

Metal nanoparticle assemblies are promising materials for nanophotonic applications due to novel linear and nonlinear optical properties arising from their plasmon modes. However, scalable fabrication approaches that provide both precision nano- and macroarchitectures, and performance commensurate with design and model predictions, have been limiti...

We present the first unified theory, to the best of our knowledge, of the response of a plasmonic nanosphere (NS) assisted by optical gain media, in the case of a NS coated with a layer of optically active dipolar dyes. We obtain the optical coherent response of the core–shell aggregate in terms of its equivalent polarizability composed of the dire...

In this paper we explore the linear and second-order nonlinear response of gold nanoparticle pairs (dimers). Despite that even-order nonlinear processes are forbidden in bulk centrosymmetric media like metals, second order nonlinear response exhibits a high degree of sensitivity for spherical nanoparticles where inversion symmetry is broken at the...

We present our results on energy transfer between donor and acceptor molecules or quantum dots near a plasmonic nanoparticle. In such systems, the Förster resonance energy transfer is strongly modified due to plasmon-mediated coupling between donors and acceptors. The transfer efficiency is determined by a competition between transfer, radiation an...

We here presents the first unified theory of the response of plasmonic nanoshells assisted by optical gain media. Our approach combines rigorous Mie scattering equations for the plasmonic structure and the density matrix formalism, which is well known in laser physics, allowing a correct description of different relaxation and energy exchange chann...

One issue in using metallic nanostructures for metamaterial applications
at optical frequencies is their high level of losses. A most promising
strategy to circumvent this obstacle is loss compensation, where the
structures are coupled to active compounds enabled to transfer energy
and therefore amplify the desired response. We here present the fir...

We study cooperative effects in energy transfer from an ensemble of
donors to an acceptor near a plasmonic nanostructure. We demonstrate
that plasmonic coupling between donors changes the energy content of the
system and hence dramatically affects transfer of its energy to an
outside acceptor. When donors are situated in a close proximity to the
me...

We study cooperative effects in energy transfer (ET) from an ensemble of
donors to an acceptor near a plasmonic nanostructure. We demonstrate that in
cooperative regime ET takes place from plasmonic superradiant and subradiant
states rather than from individual donors leading to a significant increase of
ET efficiency. The cooperative amplification...

In this chapter, we present our results on cooperative effects in hybrid plasmonic system involving a large number of fluorophores, e.g., dye molecules or semiconductor quantum dots, situated near a plasmonic nanostructure, e.g., metal nanoparticle. The optical properties of such complex systems are governed by the plasmon-mediated coupling between...

We develop a microscopic model for fluorescence of a molecule (or
semiconductor quantum dot) near a small metal nanoparticle. When a molecule is
situated close to metal surface, its fluorescence is quenched due to energy
transfer to the metal. We perform quantum-mechanical calculations of energy
transfer rates for nanometer-sized Au nanoparticles a...

A unified theory of plasmon-assisted resonance energy transfer (RET) between molecules near a metal nanostructure is developed. In a wide range of parameters, RET is dominated by plasmon-enhanced radiative transfer rather than by nonradiative transfer mechanism.

A unified theory of plasmon-assisted resonance energy transfer (RET) between molecules near a metal nanostructure is developed that maintains energy balance between transfer, dissipation, and radiation. It is shown that in a wide range of parameters, including in the near field, RET is dominated by plasmon-enhanced radiative transfer (PERT) rather...

We study cooperative emission by an ensemble of emitters, such as fluorescing molecules or semiconductor quantum dots, near
a metal nanoparticle. The primary mechanism of cooperative emission is resonant energy transfer between emitters and plasmons
rather than Dicke radiative coupling between emitters. The emission is dominated by three superradia...

We develop a unified theory of plasmon-assisted resonance energy transfer
(RET) between molecules near a metal nanostructure that maintains energy
balance between transfer, dissipation, and radiation. We show that in a wide
range of parameters, including in the near field, RET is dominated by
plasmon-enhanced radiative transfer (PERT) rather than b...

We develop a theory of cooperative emission of light by an ensemble of
emitters, such as fluorescing molecules or semiconductor quantum dots,
located near a metal nanostructure supporting surface plasmon. The
primary mechanism of cooperative emission in such systems is resonant
energy transfer between emitters and plasmons rather than the Dicke
rad...

We study theoretically fluorescence resonance energy transfer (FRET) between donor and acceptor molecules attached to a metal nanoparticle supporting localized surface plasmon. We obtain a general expression for energy transfer rate that incorporates the effects of plasmon enhancement and quenching by the nanoparticle. Specifically, we find that wh...

We study theoretically the role of dipole-dipole interactions in surface-plasmon-mediated cooperative emission of light by an ensemble of molecules near a metal nanoparticle (plasmonic Dicke effect). In a typical experimental situation, fluorescing molecules are attached to nanoparticle surface via DNA linkers with controllable lengths, and the int...

We study theoretically radiative and nonradiative decay of a single molecule near small gold nanoparticle. The local field enhancement leads to an increased radiative decay rate while the energy transfer from molecule to optically inactive electronic states in nanoparticle results in a decrease in the fluorescence quantum efficiency for small molec...

We develop a theory of cooperative emission of light by an ensemble of
emitters, such as fluorescing molecules or semiconductor quantum dots, located
near a metal nanostructure supporting surface plasmon. The primary mechanism of
cooperative emission in such systems is resonant energy transfer between
emitters and plasmons rather than the Dicke rad...

A new theoretical approach for the calculation of optical properties of
complex solutions is proposed. It is based on a dielectric matrix with included
small metallic inclusions (less than 3 nm) of spherical shape. We take into
account the mutual interactions between the inclusions and the quantum
finite-size effects. On the basis of the effective...

We identify a new mechanism for cooperative emission of light by an ensemble of N dipoles near a metal nanostructure supporting a surface plasmon. The cross talk between emitters due to the virtual plasmon exchange leads to the formation of three plasmonic superradiant modes whose radiative decay rates scale with N, while the total radiated energy...

A new mechanism for cooperative emission of light by an ensemble of dipoles near a metal nanoparticle is suggested. The emission is dominated by plasmonic super-radiant states formed due to surface plasmon exchange beetwen dipoles.

We identify a new mechanism for cooperative emission of light by an ensemble of N dipoles near a metal nanostructure supporting a surface plasmon.The cross-talk between emitters due to virtual plasmon exchange leads to a formation of three plasmonic super-radiant modes whose radiative decay rates scales with N, while the total radiated energy is th...

We study radiative and nonradiative decays of an ensemble of molecules attached to a metal nanoparticle. We show that when the system size is smaller than the radiation wavelength, the excited molecular dipoles are hybridized with each other via the nanoparticle surface plasmon, leading to cooperative plasmon-mediated emission similar to Dicke supe...

Theoretical approach is proposed to description of dielectric properties of matrix disperse systems which consists of dielectric matrix with embedded in metallic inclusions. On the basis of effective differential medium approximation the analytical expressions are obtained for the effective dielectric permittivity of the matrix disperse system with...

We study theoretically radiative and nonradiative decay of a single molecule near small gold nanoparticle. The local field enhancement leads to an increased radiative decay rate while the energy transfer from molecule to optically-inactive electronic states in nanoparticle results in a decrease in fluorescence quantum efficiency for small molecule-...

We study finite-size effects in surface-enhanced Raman scattering (SERS) from molecules adsorbed on small metal particles. Within an electromagnetic description of SERS, the enhancement of the Raman signal originates from the local field of the surface plasmon resonance in a nanoparticle. With decreasing particle sizes, this enhancement is reduced...

A microscopic model for surface-enhanced Raman scattering (SERS) from molecules adsorbed on small noblemetal nanoparticles is developed. In the absence of direct overlap of molecular orbitals and electronic states in the metal, the main enhancement source is the strong electric field of the surface plasmon resonance in a nanoparticle acting on a mo...

A microscopic approach to surface-enhanced Raman scattering (SERS) from molecules adsorbed on noble-metal nanoparticles is developed. For nanoparticle sizes smaller than 10 nm, the classical electromagnetic enhancement mechanism is modified by quantum-size effects. Using the time-dependent local field approximation, we perform a systematic analysis...

A microscopic approach to surface-enhanced Raman scattering (SERS) from molecules adsorbed on noble-metal nanoparticles is developed. For nanoparticle sizes smaller than 10 nm, the classical electromagnetic enhancement mechanism is modified by quantum-size effects. Using time-dependent local field approximation, we perform systematic analysis of SE...

154-158 Nanoparticles, surface plasmon, Raman scatteringWe present a microscopic model for surface-enhanced Raman scattering (SERS) from molecules adsorbed on small noble-metal nanoparticles. We demonstrate that, in nanometer-sized particles, SERS is determined by a competition between two distinct quantum-size effects : Landau damping of surface p...

We present a microscopic model for surface-enhanced Raman scattering (SERS) from molecules adsorbed on small noble-metal nanoparticles. We demonstrate that, in nanometer-sized particles, SERS is determined by a competition between two distinct quantum-size effects: Landau damping of surface plasmon resonance and reduced screening near nanoparticle...

We present a microscopic model for surface-enhanced Raman scattering (SERS) from molecules adsorbed on small noble-metal nanoparticles. In the absence of direct overlap of molecular orbitals and electronic states in the metal, the main enhancement source is the strong electric field of the surface plasmon resonance in a nanoparticle acting on a mol...

We study the role of a strong electron confinement on the surface-enhanced Raman scattering from molecules adsorbed on small noble-metal nanoparticles. We describe a novel enhancement mechanism which originates from the different effect that confining potential has on s-band and d-band electrons. We demonstrate that the interplay between finite-siz...

We study the role of a strong electron confinement on the surface-enhanced Raman scattering from molecules adsorbed on small noble-metal nanoparticles. We describe a novel enhancement mechanism, which originates from the different effect that confining potential has on s-band and d-band electrons. We demonstrate that the interplay between finite-si...

We present a microscopic theory of quantum-size ef-fects in surface-enhanced Raman scattering (SERS) from molecules adsorbed on small metal nanoparticles. In noble-metal nanoparticles, the confining potential has different effect on s-band and d-band electrons. Namely, the spillout of delocalized sp-electrons beyond the classi-cal nanoparticle boun...

We study the role of strong electron confinement in surface-enhanced Raman scattering from molecules adsorbed on small noble-metal particles. We describe a new source of Raman signal enhancement which originates from different behavior of sp-band and d-band electron densities near the particle boundary. In small particles, a spillover of sp-electro...

We calculate the quasistatic electromagnetic density of states for aggregates of touching spheres, in particular, linear chains and computer-generated random fractal aggregates. Multipole moments with orders of up to L=64 are taken into account for random aggregates with the number of particles of up to N=100 and up to L=8000 for linear chains. Ext...

Dust particles in space may appear as clusters of individual grains. The
morphology of these clusters could be of a fractal or more compact
nature. To investigate how the cluster morphology influences the
calculated extinction of different clusters in the wavelength range 0.1
- 100 μm, we have preformed extinction calculations of
three-dimensional...

We develop a fast and accurate solver for the forward problem of diffusion tomography in the case of several spherical inhomogeneities. The approach allows one to take into account multiple scattering of diffuse waves between different inhomogeneities. Theoretical results are illustrated with numerical examples; excellent numerical convergence and...

We study the role of a strong electron confinement on the surface-enhanced Raman scattering from molecules adsorbed on small noble-metal nanoparticles. We describe a novel enhancement mechanism which originates from the different effect that confining potential has on s-band and d-band electrons. We demonstrate that the interplay between finite-siz...

We study theoretically the role of strong electron confinement on surface-enhanced Raman scattering (SERS) from molecules adsorbed on metal nanoparticles. We describe a finite-size many-body mechanism that leads to a relative increase of SERS in small noble-metal particles. This mechanism stems from different effect of the confining potential on s-...

We describe a new finite-size many-body effect in SERS from molecules adsorbed on noble-metal nanoparticles originating from the change in the screening of surface plasmon local field in the nanoparticle surface layer

Dust particles in space may appear as clusters of individual grains. The morphology of these clusters could be of a fractal or more compact nature. To investigate how the cluster morphology influences the calculated extinction of different clusters in the wavelength range 0.1 - 100 micron, we have preformed extinction calculations of three-dimensio...

Coupled multipolar interactions between spherical nanoparticles coated with metal nanoshells are shown to yield very different optical behaviour to those between all metal nanoparticles in the same configurations. Controlled spectral tuning of absorption bands in metal shell nano-systems is shown to be easier than with all metal particles because s...

Certain dust particles in space are expected to appear as clusters of individual grains. The morphology of these clusters could be fractal or compact. To determine how these structural features would affect the interpretation of the observed interstellar extinction peak at $\sim 4.6 \mu$m, we have calculated the extinction by compact and fractal po...

Certain dust particles in space are expected to appear as clusters of individual grains. The morphology of these clusters could be fractal or compact. In this paper we study the light scattering by compact and fractal polycrystalline graphitic clusters consisting of touching identical spheres. We compare three general methods for computing the exti...

In this paper we present a method to calculate optical properties of small fractal clusters of spheres constructed in a recursive manner in the quasi static approximation. To calculate optical properties of octahedral generator of six spheres we used the dipole-dipole approximation developed in Shalaev theory. After S iterations we received a fract...

A theoretical approach is proposed to calculate an effective dielectric constant of a matrix disperse system (MDS) of metallic particles (spheres) randomly distributed and embedded in a uniform dielectric medium. Deviations from the well-known Maxwell–Garnett formula have been observed. The effective dielectric constant for different volume fractio...

A theoretical approach is formulated for the calculation of the macroscopic dielectric response of a collection of spheres at random positions embedded in a homogeneous medium. It is found that there are appreciable deviations from the Maxwell-Garnett formula. It is noted that with volume fraction increasing the pair multiple interactions between i...

A theoretical approach is formulated to the calculation of a macroscopic dielectric response of a random system of metallic spheres embedded in a uniform dielectric medium. Appreciable deviations from the Maxwell-Garnett formula are found. It is noted that, with the metal concentration increase, the role of the pair multipole interactions between t...

In this paper the light reflection coefficient of the ferromagnetic semiconductor with superlattice is calculated. It is shown that the presence of superlattice will lead to the modulation of the light absorption coefficient of the ferromagnetic semiconductor. It is shown that on the basis of the ferromagnetic semiconductor with superlattice will b...