arXiv subjects

Andrey V. Panov

Publications and source records attributed to Andrey V. Panov.

14 recordsLinked to original sources

arXiv2026

Optical Kerr nonlinearity enhancement in high-index metasurfaces via Mie void lattices

Recently, research in nanophotonics has turned toward Mie resonances in voids on the surface of high-refractive-index materials. The optical Kerr effect (OKE) in high-index membrane metasurfaces with Mie void lattices is investigated using three-dimensional finite-difference time-domain (FDTD) simulations, with gallium phosphide (GaP) as a model material. The effective nonlinear refractive index is extracted for empty spherical and truncated-cone (frustum) voids in a high-index slab. Metasurfaces with isolated Mie void resonances yield only modest effective OKE enhancement, up to a factor of ten relative to bulk GaP. Mie void resonances in GaP metasurfaces are observable when the separation between voids exceeds approximately 220 nm; otherwise, modes in the high-index material between the voids prevail. A much stronger response arises from the later modes developing in the high-index regions between closely spaced voids. While the nonlinear figure of merit of Mie-void metasurfaces is limited for applications relying solely on energy-density enhancement, the open-cavity geometry offers advantages for hybrid systems that require access to the confined field, such as quantum emitters or nonlinear materials infiltrated into the voids.

physics.optics↗

arXiv2025

Enhanced Optical Kerr Effect in Metasurfaces Featuring Arrays of Rotated Rectangular Holes via Trapped-Mode Resonances

Recent advances in nanophotonics have demonstrated that various optical resonances in nanostructures can achieve strong field confinement with substantially suppressed scattering. This study investigates the optical Kerr effect (OKE) enhancement in high-refractive-index metasurfaces featuring non-BIC trapped-mode resonances, using gallium phosphide (GaP) as a model material. Three-dimensional finite-difference time-domain simulations reveal a significant enhancement of the effective second-order refractive index, reaching values up to 700 times greater than bulk GaP. The numerical results show strong electromagnetic field localization at the trapped-mode resonance, characterized by a wide transmittance dip (low Q-factor) and near-unity reflectance. Remarkable stability is observed, with the OKE enhancement maintaining less than 5\% variation for moderate polarization angles and tolerating random nanohole rotations that model fabrication imperfections. Compared to bound states in the continuum (BIC), the non-BIC trapped mode demonstrates superior robustness to structural disorder while achieving comparable nonlinear enhancement. These findings suggest promising applications in reflective nonlinear optics, particularly for high harmonic generation and polarization-insensitive photonic devices.

physics.optics↗

arXiv2023

Optical Kerr nonlinearity of dielectric nanohole array metasurfaces with different hole shapes near the anapole state

At present, optical anapole resonances in nanostructures have attracted increasing attention due to the strong field confinement and substantially suppressed scattering. This study provides the results of three-dimensional finite-difference time-domain simulations exhibiting the possibility of the anapole state in high refractive index dielectric nanohole array metasurfaces having different profiles of the holes (square, hexagon, and octagon). Behavior of the effective optical Kerr nonlinearity of the metasurfaces in the vicinity of the anapole state is investigated. Depending on the geometry, the absolute value of the effective nonlinear Kerr coefficient of the metasurface may be up to three orders of magnitude greater than that of the unstructured film. A square transverse section of the nanohole is preferable for the optical Kerr effect in the holey metasurfaces. The effect of the random rotation of the square holes representing the metasurface irregularity on the optical nonlinearity is examined. As a result, the dielectric nanohole array metasurfaces display a concrete possibility to have the anapole state with large enhancement of the optical nonlinearity.

physics.optics↗

arXiv2022

Optical Kerr nonlinearity of dielectric nanohole array metasurface in proximity to anapole state

Metasurfaces have attracted a great deal of attention from researchers due to their prominent optical properties. In particular, metasurfaces may consist of structures possessing optical anapole resonances with strong field confinement and substantially suppressed scattering. As a result, such nanostructures display enhanced nonlinear optical properties. In this paper by means of three-dimensional finite-difference time-domain simulations, the ability of anapole modes in high-index dielectric metasurfaces with circular nanopores is shown. In the vicinity of the anapole state, the effective optical Kerr nonlinearity increases by orders of magnitude. Simultaneously, the optical transmission of the metasurface can reach high values up to unity.

physics.optics↗

arXiv2020

Giant enhancement and sign inversion of optical Kerr nonlinearity in random high index nanocomposites near Mie resonances

High index dielectric nanoantennas excited at Mie-type resonances have exhibited enormous enhancement of optical nonlinearity. Such nanostructures have been actively studied by researchers in the last years. The present work provides the first numerical analysis study of the optical Kerr effect of nanocomposites consisting of high refractive index (GaP) spheres at the wavelength of 532~nm. This is done by means of three-dimensional finite-difference time-domain (FDTD) simulations. The effective nonlinear refractive index of $0.8$~$μ$m thick nanocomposites and metasurfaces is evaluated. It is shown that the optical Kerr nonlinearity of the nanocomposites rises by orders in proximity to Mie resonances and may exceed the second-order refractive index of the bulk material. It is revealed that the sign of the effective optical Kerr coefficient is inverted near the Mie resonances. This effect may be of interest in developing nonlinear optical metadevices.

physics.optics↗

arXiv2020

Optical Kerr nonlinearity of arrays of all-dielectric high index nanodisks in the vicinity of the anapole state

The nonlinear optical properties of the high index nanoparticles are boosted at the anapole state. Researchers intensively study this phenomenon as promising for various applications. In this work, the nonlinear optical Kerr effect of disordered and square lattice metasurfaces of GaP nanodisks is investigated as a function of the disk size in the vicinity of the anapole state at the wavelength of 532 nm. When the sizes of the nanodisks are close to the anapole state, the effective second order refractive index of the metasurface increases exponentially. On approaching the anapole state, the sign of the effective second order refractive index is inverted. The absolute value of the effective nonlinear Kerr coefficient of the square lattice metasurface is higher than that of the disordered array of nanodisks. The absolute value of the effective second order refractive index in proximity to the anapole state is an order of magnitude higher than that at non-anapole resonances of the disordered metasurfaces consisting of the nanodisks or spheres.

physics.optics↗

arXiv2020

Optical Kerr nonlinearity of disordered all-dielectric resonant high index metasurfaces with negative refraction

The optical Kerr effect of material with negative refraction is estimated for the first time. This is done via three-dimensional finite-difference time-domain (FDTD) simulations of disordered bidisperse metasurfaces consisting of high index (GaP) spheres at the wavelength of 532~nm. The metasurfaces comprise spherical particles randomly arranged on plane having two sizes close to the magnetic and electric dipole Mie resonances. The real part of the effective nonlinear refractive index of the metasurfaces is computed in the vicinity of the Mie resonances where the metasurface possesses the negative index of refraction. The optical Kerr nonlinearity has a peak under the condition for the negative refraction. Intensity-dependent refractive index of the bidisperse metasurfaces is studied through concentration transition to the negative refraction state. It is shown that the nonlinear Kerr coefficient of the monolayer metasurface has maximum when the effective linear refractive index is close to zero.

physics.optics↗

arXiv2020

Possibility of negative refraction for visible light in disordered all-dielectric resonant high index metasurfaces

Effective refractive index of disordered all-dielectric metasurfaces consisting of gallium phosphide (GaP) spheres is studied by means of three-dimensional finite-difference time-domain (FDTD) simulations at the wavelength of 532~nm. It is shown that a mixture of the high index nanoparticles with sizes close to the first magnetic and electric resonances randomly dispersed on metasurface may possess negative refraction. The dependence of the metasurface effective refractive index on the nanoparticle concentration and size is constructed. The feasibility of negative refraction at large concentrations of the high index resonant spheres is demonstrated. The negative effective refractive index is exhibited only for a monolayer of GaP spheres.

physics.optics↗

arXiv2018

Retrieving nonlinear refractive index of nanocomposites using finite-difference time-domain simulations

In this Letter, it is proposed a method which utilizes three-dimensional finite-difference time-domain (FDTD) simulations of light propagation for restoring the effective Kerr nonlinearity of nanocomposite media. In this approach, a dependence of the phase shift of the transmitted light on the input irradiance is exploited. The reconstructed values of the real parts of the nonlinear refractive index of a structure of randomly arranged spheres are in good agreement with the predictions of the effective medium approximations.

physics.optics↗

arXiv2016

Hollow core Bragg fiber with antiresonant intermediate layer

By means of the transfer matrix method, the optical properties of fibers with a distinct intermediate layer between a hol-low core and periodic cladding are calculated. The periodic cladding consists of two types of the alternating layers. The intermediate layer has distinct thickness and refractive index. Depending on these parameters, the fiber can work in the single-mode or multi-mode regimes. In the multi-mode regime, the optical loss of the smallest loss mode can be de-creased by increasing the thickness of the layer. In the single-mode regime, the optical loss falls with a rise in the refrac-tive index of the intermediate layer. The optical properties of the fiber are determined by the antiresonance reflection from the intermediate layer and the Bragg reflection from the periodic cladding. Selecting the parameters of the interme-diate layer, the optical loss of the fiber in the single-mode regime can be reduced by an order of magnitude over the loss of the traditional Bragg fiber.

physics.optics↗

arXiv2013

Impact of interparticle dipole-dipole interactions on optical nonlinearity of nanocomposites

In this paper, effect of dipole-dipole interactions on nonlinear optical properties of the system of randomly located semiconductor nanoparticles embedded in bulk dielectric matrix is investigated. This effect results from the nonzero variance of the net dipole field in an ensemble. The analytical expressions describing the contribution of the dipole-dipole coupling to nonlinear dielectric susceptibility are obtained. The derived relationships are applicable over the full range of nanoparticle volume fractions. The factors entering into the contribution and depending on configuration of the dipoles are calculated for several cases. It is shown that for the different arrangements of dipole alignments the relative change of this contribution does not exceed 1/3.

cond-mat.mes-hall↗

arXiv2013

Effect of dipolar interactions on optical nonlinearity of two-dimensional nanocomposites

In this work, we calculate the contribution of dipole-dipole interactions to the optical nonlinearity of the two-dimensional random ensemble of nanoparticles that possess a set of exciton levels, for example, quantum dots. The analytical expressions for the contributions in the cases of TM and TE-polarized light waves propagating along the plane are obtained. It is shown that the optical nonlinearity, caused by the dipole-dipole interactions in the planar ensemble of the nanoparticles, is several times smaller than the similar nonlinearity of the bulk nanocomposite. This type of optical nonlinearity is expected to be observed at timescales much larger than the quantum dot exciton rise time. The proposed method may be applied to various types of the nanocomposite shapes.

cond-mat.mes-hall↗

arXiv2012

Probability distribution function of dipolar field in two-dimensional spin ensemble

We theoretically determine the probability distribution function of the net field of the random planar structure of dipoles which represent polarized particles. At small surface concentrations c of the point dipoles this distribution is expressed in terms of special functions. At the surface concentrations of the dipoles as high as 0.6 the dipolar field obey the Gaussian law. To obtain the distribution function within transitional region c<0.6, we propose the method based on the cumulant expansion. We calculate the parameters of the distributions for some specific configurations of the dipoles. The distribution functions of the ordered ensembles of the dipoles at the low and moderate surface concentrations have asymmetric shape with respect to distribution medians. The distribution functions allow to calculate various physical parameters of two-dimensional interacting nanoparticle ensembles.

cond-mat.stat-mech↗

arXiv2012

Dipolar ordering of random two-dimensional spin ensemble

We theoretically study the randomly positioned two-dimensional system of interacting magnetic dipoles representing the monolayer arrays of single-domain particles. It is showed the onset of the dipolar in-plane superferromagnetic ordering of Ising spins at the surface concentrations of nanoparticles above 0.24. The critical concentration of particles with random easy axis arrangement at zero temperature is 0.65. It is demonstrated that the ensemble with Ising arrangement of spins is ordered at high temperatures close to a particle Curie point.

cond-mat.mes-hall↗