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Abstract Optical binding of metal nanoparticles (NPs) provides a promising way to create tunable photonic materials and devices, where the ultrastrong interparticle interaction is generally attributed to the localized surface plasmon resonances of NPs. Here, it is revealed that the optical binding of metal NPs can be self‐reinforced by the plasmonic surface lattice resonances (PSLRs) associated with the discrete NP arrays. Through simulations and experiments, it is demonstrated that PSLRs can spontaneously arise in optically bound gold NP chains with just a few NPs when they are relatively large, e.g., 150 nm in diameter. Additionally, the PSLRs are enhanced by increasing the chain length, leading to stronger optical binding stiffness. These results reveal a previously unidentified factor that contributes to the ultrastrong optical binding of metal NPs. More importantly, this study presents a prospect for building freestanding and reconfigurable NP arrays that naturally support PLSRs for sensing and other applications. 

Optical tweezers can control the position and orientation of individual colloidal particles in solution. Such control is often desirable but challenging for single-particle spectroscopy and microscopy, especially at the nanoscale. Functional nanoparticles that are optically trapped and manipulated in a three-dimensional (3D) space can serve as freestanding nanoprobes, which provide unique prospects for sensing and mapping the surrounding environment of the nanoparticles and studying their interactions with biological systems. In this perspective, we will first describe the optical forces underlying the optical trapping and manipulation of microscopic particles, then review the combinations and applications of different spectroscopy and microscopy techniques with optical tweezers. Finally, we will discuss the challenges of performing spectroscopy and microscopy on single nanoparticles with optical tweezers, the possible routes to address these challenges, and the new opportunities that will arise.