Nanoscale Tunable Optical Binding Mediated by Hyperbolic Metamaterials

Abstract

Carefully designed nanostructures can inspire new type of optomechanical interactions and allow surpassing limitations set by classical diffractive optical elements. Apart from strong near-field localization, nanostructured environment allows controlling scattering channels and might tailor many-body interactions. Here we investigate an effect of optical binding, where several particles demonstrate a collective mechanical behaviour of bunching together in a light field. In contrary to classical binding, where separation distances between particles are diffraction limited, an auxiliary hyperbolic metasurface is shown here to break this barrier by introducing several controllable near-field interaction channels. Strong material dispersion of the hyperbolic metamaterial along with high spatial confinement of optical modes, which it supports, allow achieving superior tuning capabilities and efficient control over binding distances on the nanoscale. In addition, a careful choice of the metamaterial slab's thickness enables decreasing optical binding distances by orders of magnitude compared to free space scenarios due to the multiple reflections of volumetric modes from the substrate. Auxiliary tunable metamaterials, which allow controlling collective optomechanical interactions on the nanoscale, open a venue for new investigations including collective nanofluidic interactions, triggered bio-chemical reactions and many others.

Terahertz binding of nanoparticles based on graphene surface plasmons excitations

“…In this range, the normalized total force reaches a value ≈ 1.4x10 −3 pN, i.e., a value of 0.07pN for intensities of 50mW/µm 2 . Taking into account that the period of the force is λ p = 0.83µm, the trapping potential of the optical binding approaches 4k B T at room temperature and moderate intensities involved in optical trapping [9,10]. This fact can be seen in Figure 2c, where we have calculated the potential energy of the optical binding for parallel polarization by integration of the force for an intensity of 50mW/µm 2 (we take the potential energy as null for the equilibrium position 2).…”

“…Recently, a planar metallic or metamaterial structure was proposed as an optical binding tool, in which the propagating eigenmodes excited on the surface play an essential role on the increment of the interaction force between dielectric nano particles. The binding distance between nanoparticles is defined by the eigenmode wavelength which, in case of bound modes such as surface plasmons, is smaller than the photon wavelength [9,10].…”

Dispersion properties of plasmonic sub-wavelength elliptical wires wrapped with graphene

“…Polarizabilities ( 23) and ( 32) constitutes the central object for optical interactions where the quasistatic regime is applicable [38], such as enhanced and confined optical near-fields [39], metasurface and metagrating applications [40] and nanoparticles bonding [41,42,43]. In the present work, we use these expressions to calculate the power scattered by the particle in the quasistatic limit as follows.…”

Multipole Engineering of Attractive−Repulsive and Bending Optical Forces

“…[ 25–28 ] For example, hyperbolic metamaterials and metasurfaces introduced a bunch of new effects, including tractor beams, antitrapping, and several others. [ 29–35 ] Other types of auxiliary optomechanical structures include metalenses, [ 36 ] laser‐printed manipulators, [ 37 ] plasmonic Archimedes spiral lenses, [ 38 ] photonic hooks, [ 39,40 ] photonic nanojets [ 41–43 ] and many others.…”

“…Being started with the goal of nanoscale localization of particles beyond the classical diffraction limit, plasmonic tweezers concept [4], [24] and related auxiliary tools were found to be an efficient approach for tailoring nanoscale mechanical motion with light [25]- [28]. For example, hyperbolic metamaterials and metasurfaces introduced a bunch of new effects, including tractor beams, anti-trapping and several others [29] [30], [31]- [34] [35]. Other types of auxiliary optomechanical structures include metalenses [36], laser-printed manipulators [37], plasmonic Archimedes spiral lens [38], photonic hooks [39], [40], photonic nanojets [41], [42], [43] and many others.…”