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The concept of lateral optical force (LOF) is of general interest in optical manipulation as it releases the constraint of intensity gradient in tightly focused light, yet such a force is normally limited to exotic materials and/or complex light fields. Here, we report a general and controllable LOF in a nonchiral elongated nanoparticle illuminated by an obliquely incident plane wave. Through computational analysis, we reveal that the sign and magnitude of LOF can be tuned by multiple parameters of the particle (aspect ratio, material) and light (incident angle, direction of linear polarization, wavelength). The underlying physics is attributed to the multipolar interplay in the particle, leading to a reduction in symmetry. Direct experimental evidence of switchable LOF is captured by polarization-angle-controlled manipulation of single Ag nanowires using holographic optical tweezers. This work provides a minimalist paradigm to achieve interface-free LOF for optomechanical applications, such as optical sorting and light-driven micro/nanomotors. It is a significant challenge to create an interface-free lateral optical force under the illumination of a single polarized plane wave. Here, the authors provide a minimalist paradigm to address this challenge by exploiting multipolar interplay in a single elongated particle. [ABSTRACT FROM AUTHOR]

We report the first experimental realization of all-optical trapping and manipulation of plasmonic nanowires in three dimensions. The optical beam used for trapping is the Fourier transform of a linearly polarized Bessel beam (termed FT-Bessel). The extended depth of focus of this beam enables the use of a retroreflection geometry to cancel radiation pressure in the beam propagation direction, making it possible to trap highly scattering and absorbing silver nanowires. Individual silver nanowires with lengths of several micrometers can be positioned by the trapping beam with a precision better than 100 nm and are oriented by the polarization of the trapping light with a precision of approximately 1°. Multiple nanowires can be trapped simultaneously in spatially separated maxima of the trapping field. Since trapping in the interferometric FT-Bessel potential is robust in bulk solution and near surfaces, it will enable the controlled assembly of metal nanowires into plasmonic nanostructures. [ABSTRACT FROM AUTHOR]

In article number 1808258, Zijie Yan and Fan Nan report a new type of optical tweezers for enhanced optical trapping and binding of nanoparticles. A single silver nanowire allows for the creation of an interferometric optical field to guide the self‐organization of colloidal metal and dielectric nanoparticles in a spatially extended and linearly polarized laser beam, leading to ordered hexagonal nanoparticle arrays under an optimized polarization direction. [ABSTRACT FROM AUTHOR]

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. A single silver nanowire allows for the creation of an interferometric optical field to guide the self‐organization of colloidal nanoparticles in a spatially extended and linearly polarized laser beam. As a result, large‐scale ordered hexagonal arrays can be assembled from nanoparticles in solution by controlling the polarization direction of incident light. [ABSTRACT FROM AUTHOR]