Abstract
Abstract Optical binding is a laser-induced inter-particle force that exists between two or more particles subjected to off-resonant light. It is one of the key tools in optical manipulation of particles. Distinct from the single-particle forces which operate in optical trapping and tweezing, it enables the light-induced self-assembly of non-contact multi-particle arrays and structures. Whilst optical binding at the microscale between microparticles is well-established, it is only within the last few years that the experimental difficulties of observing nanoscale optical binding between nanoparticles have been overcome. This hurdle surmounted, there has been a sudden proliferation in observations of nanoscale optical binding, where the corresponding theoretical understanding and predictions of the underlying nanophotonics have become ever more important. This article covers these new developments, giving an overview of the emergent field of nanoscale optical binding.
Highlights
Optical binding is a laser-induced inter-particle force that exists between two or more particles subjected to off-resonant light
Whilst optical binding at the microscale between microparticles is wellestablished, it is only within the last few years that the experimental difficulties of observing nanoscale optical binding between nanoparticles have been overcome. This hurdle surmounted, there has been a sudden proliferation in observations of nanoscale optical binding, where the corresponding theoretical understanding and predictions of the underlying nanophotonics have become ever more important
The vast majority of studies in the field are concerned with microscale optical binding, an extensive amount of research in the last 10–15 years has been centred on optical binding between nanoparticles. This nanoscale optical binding is the focus of the following Review, where we provide an overview of both experimental and theoretical studies extending to the latest, novel effects that arise on input of structured light, irradiation of chiral nanoparticles, and the role of plasmonics to name just some of the key developments
Summary
The laser-induced optical force that exists between two or more micron- or submicron-sized particles, when subjected to a moderately intense off-resonant laser light at optical frequencies, is commonly known as optical binding. In the case of laser tweezers the particles are localised in a microscale volume, commonly supported in a passive liquid support medium to offset the effect of gravity [33] It is with such particles, already held almost stationary in an optical field, that optical binding exerts its effect as a stabilising influence on inter-particle separations. Either the first (R−3) or the final (R−1) term will dominate as the asymptotic form under important limiting conditions – the near- and far-fields, respectively In the latter, where the inter-particle coupling is mediated by a fully retarded radiation field, the R−1 distance-dependent decay may be considered a novelty when compared to the Figure 1: Optical binding between nanoparticles A and B separated by a displacement vector R. The most significant aspect is that the wave vector k is multiplied by the refractive index of the support medium for the laser wavelength, serving in effect
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
