arXiv subjects

Natalia Kostina

Publications and source records attributed to Natalia Kostina.

6 recordsLinked to original sources

arXiv2026

Directional Scattering-Induced Optical Forces on a Mie Particle near a Metal Interface

Optical manipulation of Mie-resonant dielectric nanoparticles is strongly influenced by their enhanced scattering and multipolar response, which fundamentally modifiesthe balance of optical forces. In this work, we study the optical forces acting on a resonant dielectric nanoparticle placed near a metal interface, where scattering occurs into both free-space and surface plasmon-polariton (SPP) channels. We show that the interference of electric and magnetic dipole moments leads to highly directional scattering in these channels, and the direction and magnitude of the scattering-induced force are directly linked to the angular directivity of the corresponding radiation channels. We show that in a cross-beam configuration, where the radiation-pressure contribution is suppressed, the optical force can be changed for almost 2π in a wide range of particle sizes that provides a route toward optical sorting of resonant nanoparticles.

physics.optics↗

arXiv2021

Optical Pulling and Pushing Forces via Bloch Surface Waves

Versatile manipulation of nano- and microobjects underlies the optomechanics and a variety of its applications in biology, medicine, and lab-on-a-chip platforms. For flexible tailoring optical forces, as well as for extraordinary optomechanical effects, additional degrees of freedom should be introduced into the system. Here, we demonstrate that photonic crystals provide a flexible platform for nanoparticles optical manipulation due to both Bloch surface waves (BSWs) and the complex character of the reflection coefficient paving a way for complex optomechanical interactions control. We demonstrate that appearance of enhanced pulling and pushing transversal optical forces acting on a single bead placed above a one-dimensional photonic crystal due to directional excitation of Bloch surface wave at the photonic crystal interface. Our theoretical results, which are supported with numerical simulations, demonstrate angle or wavelength assisted switching between BSW-induced optical pulling and pushing forces. Easy-to-fabricate for any desired spectral range photonic crystals are shown to be prospective for precise optical sorting of nanoparticles, especially for core-shell nanoparticles, which are difficult to sort with conventional optomechanical methods. Our approach opens opportunities for novel optical manipulation schemes and platforms and enhanced light-matter interaction in optical trapping setups.

physics.optics↗

arXiv2018

Optomechanical manipulation with hyperbolic metasurfaces

Auxiliary nanostructures introduce additional flexibility into optomechanical manipulation schemes. Metamaterials and metasurfaces capable to control electromagnetic interactions at the near-field regions are especially beneficial for achieving improved spatial localization of particles, reducing laser powers required for trapping, and for tailoring directivity of optical forces. Here, optical forces acting on small particles situated next to anisotropic substrates, are investigated. A special class of hyperbolic metasurfaces is considered in details and is shown to be beneficial for achieving strong optical pulling forces in a broad spectral range. Spectral decomposition of the Green functions enables identifying contributions of different interaction channels and underlines the importance of the hyperbolic dispersion regime, which plays the key role in optomechanical interactions. Homogenised model of the hyperbolic metasurface is compared to its metal-dielectric multilayer realizations and is shown to predict the optomechanical behaviour under certain conditions related to composition of the top layer of the structure and its periodicity. Optomechanical metasurfaces open a venue for future fundamental investigations and a range of practical applications, where accurate control over mechanical motion of small objects is required.

physics.optics↗

arXiv2017

Optical binding via surface plasmon polariton interference

Optical binding allows creation of mechanically stable nanoparticle configurations owing to formation of self-consistent optical trapping potentials. While the classical diffraction limit prevents achieving deeply subwavelength arrangements, auxiliary nanostructures enable tailoring optical forces via additional interaction channels. Here, a dimer configuration next to metal surface was analyzed in details and the contribution of surface plasmon polariton waves was found to govern the interaction dynamics. It was shown that the interaction channel, mediated by resonant surface waves, enables achieving subwavelength stable dimers. Furthermore, the vectorial structure of surface modes allows binding between two dipole nanoparticles along the direction of their dipole moments, contrary to vacuum binding, where a stable configuration is formed in the direction oriented perpendicularly to the polarization of dipole moments. In addition, the enhancement of optical binding stiffness for one order of magnitude was predicted owing to the surface plasmon polariton interaction channel. These phenomena pave a way for developing new flexible optical manipulators, allowing for the control over a nanoparticle trajectory on subwavelength scales and opens a room of opportunities for optical-induced anisotropic, i.e. with different periods along the field polarization as well as perpendicular to it, organization of particles on a plasmonic substrate.

physics.optics↗

arXiv2013

About the survey of propagandistic messages in contemporary social media

This paper presents the research results that have identified a set of characteristic parameters of propagandistic messages. Later these parameters can be used in the algorithm creating special user-oriented propagandistic messages to improve distribution and assimilation of information by users.

cs.SI↗

arXiv2012

Analytical model of misinformation of a social network node

This paper presents the research of the influence of cognitive, behavioral, representational factors on the susceptibility of the participants in social networks to misinformation, as well as on the activity of the nodes in this regard. The importance of this research consists of method of blocking the propaganda. This is very important because when people involuntarily acquire information some of them experience an undesired change in their social attitude. Such phenomena typically lead towards the information warfare. A model was developed during this research for calculating the level of misinformation of the social network participant (network node) based on the model of iterative learning process.

cs.SI↗