- 标题
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Stable Fano-like plasmonic resonance: its impact on the reversal of far- and near-field optical binding force
摘要： Even for a 100 nm interparticle distance or a small change in particle shape, optical Fano-like plasmonic resonance mode usually vanishes completely. It would be remarkable if stable Fano-like resonance could somehow be achieved in distinctly shaped nanoparticles for more than 1 μm interparticle distance, which corresponds to the far electromagnetic field region. If such far-field Fano-like plasmonic resonance can be achieved, controlling the reversal of the far-field binding force can be attained, like the currently reported reversals for near-field cases. In this work, we have proposed an optical set-up to achieve such a robust and stable Fano-like plasmonic resonance, and comparatively studied its remarkable impact on controlling the reversal of near- and far-field optical binding forces. In our proposed set-up, the distinctly shaped plasmonic tetramers are half immersed (i.e. air–benzene) in an inhomogeneous dielectric interface and illuminated by circular polarized light. We have demonstrated significant differences between near- and far-field optical binding forces along with the Lorentz force field, which partially depends on the object’s shape. A clear connection is shown between the far-field binding force and the resonant modes, along with a generic mechanism to achieve controllable Fano-like plasmonic resonance and the reversal of the optical binding force in both far- and near-field configurations.
关键词： Fano resonance,plasmonic,optical binding force,tetramer,Lorentz force
更新于2025-09-23 15:21:01
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Self-trapped nanoparticle binding via waveguide mode
摘要： In this paper, we study a stable optomechanical system based on a nanoparticle chain coupled to a waveguide mode. Under the plane wave excitation the nanoparticles form a stable self-organized periodic array along waveguide axis through the transverse binding effect. We show that owing to the long-range interaction between the nanoparticles the trapping potential for each nanoparticle in the chain increases linearly with the system size, making the formation of long chains more favourable. We show that for an optical nanofiber platform the binding energy for two nanoparticles is in the range of 9 ÷ 13 kT reaching the value of 110 kT when the chain size is increased to 20 nanoparticles. We also suggest the geometry of the two counter-propagating plane waves excitation, which will allow trapping the nanoparticles close to the optical nanofiber providing efficient interaction between the nanoparticles and the nanofiber.
关键词： one-dimensional interaction,nanofiber,Optical binding,self-assembly,optical force
更新于2025-09-12 10:27:22
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Optical Trapping, Optical Binding, and Rotational Dynamics of Silicon Nanowires in Counter-Propagating Beams
摘要： Silicon nanowires are held and manipulated in controlled optical traps based on counter-propagating beams focused by low numerical aperture lenses. The double-beam configuration compensates light scattering forces enabling an in-depth investigation of the rich dynamics of trapped nanowires that are prone to both optical and hydrodynamic interactions. Several polarization configurations are used, allowing the observation of optical binding with different stable structure as well as the transfer of spin and/or orbital momentum of light to the trapped silicon nanowires. Accurate modeling based on Brownian dynamics simulations with appropriate optical and hydrodynamic coupling confirms that this rich scenario is crucially dependent on the non-spherical shape of the nanowires. Such increased level of optical control of multi-particle structure and dynamics open perspectives for nanofluidics and multicomponent light-driven nanomachines.
关键词： optical binding,silicon nanowires,light-driven rotations,Optical trapping,light angular momentum
更新于2025-09-09 09:28:46
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Tailored long range forces on polarizable particles by collective scattering of broadband radiation
摘要： Collective coherent light scattering by polarizable particles creates surprisingly strong, long range inter-particle forces originating from interference of the light scattered by different particles. While for monochromatic laser beams this interaction decays with the inverse distance, we show here that in general the effective interaction range and geometry can be controlled by the illumination bandwidth and geometry. As generic example we study the modi?cations inter-particle forces within a 1D chain of atoms trapped in the ?eld of a con?ned optical nano?ber mode. For two particles we ?nd short range attraction as well as optical binding at multiple distances. The range of stable distances shrinks with increasing light bandwidth and for a very large bandwidth ?eld as e.g. blackbody radiation. We ?nd a strongly attractive potential up to a critical distance beyond which the force gets repulsive. Including multiple scattering can even lead to the appearance of a stable con?guration at a large distance. Such broadband scattering forces should be observable contributions in ultra-cold atom interferometers or atomic clocks setups. They could be studied in detail in 1D geometries with ultra-cold atoms trapped along or within an optical nano?ber. Broadband radiation force interactions might also contribute in astrophysical scenarios as illuminated cold dust clouds.
关键词： self-ordering,optical binding,fiber optics
更新于2025-09-09 09:28:46
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Reactive optical matter: light-induced motility in electrodynamically asymmetric nanoscale scatterers
摘要： From Newton’s third law, which is known as the principle of actio et reactio, we expect the forces between interacting particles to be equal and opposite for closed systems. Otherwise, “nonreciprocal” forces can arise. This has been shown theoretically in the interaction between dissimilar optically trapped particles that are mediated by an external field. As a result, despite the incident external field not having a transverse component of momentum, the particle pair experiences a force in a direction that is transverse to the light propagation direction. In this letter, we directly measure the net nonreciprocal forces in electrodynamically interacting asymmetric nanoparticle dimers and nanoparticle structures that are illuminated by plane waves and confined to pseudo one-dimensional geometries. We show via electrodynamic theory and simulations that interparticle interactions cause asymmetric scattering from heterodimers. Therefore, forces are actually a consequence of momentum conservation. Our study demonstrates that asymmetric scatterers exhibit directed motion due to the breakdown of mirror symmetry in their electrodynamic interactions with external fields.
关键词： momentum conservation,nonreciprocal forces,optical binding,electrodynamic interactions,nanoparticle dimers
更新于2025-09-09 09:28:46
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Silver-Nanowire-Based Interferometric Optical Tweezers for Enhanced Optical Trapping and Binding of Nanoparticles
摘要： Light-induced self-assembly offers a new route to build mesoscale optical matter arrays from nanoparticles (NPs), yet the low stability of optical matter systems limits the assembly of large-scale NP arrays. Here it is shown that the interferometric optical fields created by illuminating a single Ag nanowire deposited on a coverslip can enhance the electrodynamic interactions among NPs. The Ag nanowire serves as a plasmonic antenna to shape the incident laser beam and guide the optical assembly of colloidal metal (Ag and Au) and dielectric (polystyrene) NPs in solution. By controlling the laser polarization direction, both the mesoscale interactions among multiple NPs and the near-field coupling between the NPs and nanowire can be tuned, leading to large-scale and stable optical matter arrays consisting of up to 60 NPs. These results demonstrate that single Ag nanowires can serve as multifunctional antennas to guide the optical trapping and binding of multiple NPs and provide a new strategy to control electrodynamic interactions using hybrid nanostructures.
关键词： self-assembly,colloidal nanoparticles,optical binding,interferometric optical tweezers
更新于2025-09-04 15:30:14