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

Metal-Dielectric Nanodimers with Hybridized Resonances Probed by Second-Harmonic Polarization

We fabricate hybrid nanodimers made of gold and barium titanate nanoparticles by a pick-and-place technique. By overlapping their resonances, we achieve 100-times enhancement of the second-harmonic signal at the hybridized mode while reshaping its polarization

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 Green\u27s 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. Homogenized model of the hyperbolic metasurface is compared to its metal-dielectric multilayer realizations and is shown to predict the optomechanical behavior 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

Оптические силы, действующие на частицы вблизи фотонного кристалла

We consider optical forces acting on resonant particles located near the surface of a photonic crystal (PC). The band structure of the PC makes it possible to change the direction of propagation of the BSW (Bloch surface wave) to the opposite when varying the wavelength of the incident radiation, which leads to a change in the direction of the reactive optical force component. Therefore, there is an effect of switching between the modes of optical attraction and repulsion of particles in narrow spectral ranges, which is prospective for precise sorting of resonant particles. Here we consider sorting of core-shell dielectric-gold nanoparticles with varying shell thicknessМы рассматриваем оптические силы, действующие на резонансные частицы, расположенные вблизи поверхности фотонного кристалла. Зонная структура ФК позволяет изменять направления распространения ПВБ на противоположное при варьировании длины волны падающего излучения, что приводит к изменению направления реактивной оптической силы. Таким образом, имеет место эффект переключения между режимами оптического притяжения и отталкивания частиц в узких спектральных диапазонах, что может быть использовано для прецизионной сортировки резонансных части

Surface Plasmon Polariton Assisted Optical Pulling Force

We demonstrate both analytically and numerically the existence of optical pulling forces acting on particles located near plasmonic interfaces. Two main factors contribute to the appearance of this negative recoil force. The interference between the incident and reflected waves induces a rotating dipole with an asymmetric scattering pattern, while the directional excitation of surface plasmon polaritons (SPPs) enhances the linear momentum of scattered light. The strongly asymmetric SPP excitation is determined by spin-orbit coupling of the rotating dipole and surface plasmon polariton. As a result of the total momentum conservation, the force acting on the particle points in a direction opposite to the incident wave propagation. We derive analytical expressions for the force acting on dipolar particles placed in the proximity of plasmonic surfaces. Analytical expressions for this pulling force are derived within the dipole approximation and are in excellent agreement with results of electromagnetic numerical calculations. The forces acting on larger particles are analyzed numerically, beyond the dipole approximation. The authors demonstrate the generation of attractive optical force acting on nanoparticle in the vicinity of metal surface due to surface plasmon polariton (SPP) excitation. The excitation of SPP has strongly asymmetrical character which is determined by spin-orbit coupling of the induced rotating dipole and SPP mode. As a result of the total momentum conservation, the force acting on the particle points in a direction opposite to the incident wave propagation. This effect can be utilized for effective optomechanical control of nanoobjects over metallic surface

Resonant transmission of light in chains of high-index dielectric particles

We study numerically, analytically, and experimentally the resonant transmission of light in a waveguide formed by a periodic array of high-index dielectric nanoparticles with a side-coupled resonator. We demonstrate that a resonator with high enough Q-factor provides the conditions for the Fano-type interference allowing one to control the resonant transmission of light. We suggest a practical realization of this resonant effect based on the quadrupole resonance of a dielectric particle and demonstrate it experimentally for ceramic disks at microwave frequencies