Assembly of 3D plasmonic metamolecules by 2D AFM nanomanipulation of highly uniform and smooth gold nanospheres

TL;DR

This paper demonstrates a method to assemble 3D plasmonic metamolecules using AFM nanomanipulation of gold nanospheres on a nanohole template, enabling precise control over their structure and electromagnetic properties.

Contribution

The study introduces a versatile approach for constructing 3D plasmonic clusters via AFM nanomanipulation on nanohole templates, expanding the design space for artificial electromagnetism.

Findings

Successfully assembled various 3D plasmonic clusters with nanometer precision.

Fully rationalized 3D plasmonic modes through numerical calculation and spectroscopy.

Demonstrated the potential for designing advanced metamaterials and metafluids.

Abstract

Atomic force microscopy (AFM) nanomanipulation has been viewed as a deterministic method for the assembly of plasmonic metamolecules because it enables unprecedented engineering of clusters with exquisite control over particle number and geometry. Nevertheless, the dimensionality of plasmonic metamolecules via AFM nanomanipulation is limited to 2D, so as to restrict the design space of available artificial electromagnetisms. Here, we show that 2D nanomanipulation of the AFM tip can be used to assemble 3D plasmonic metamolecules in a versatile and deterministic way by dribbling highly spherical and smooth gold nanospheres (NSs) on a nanohole template rather than on a flat surface. Various 3D plasmonic clusters with controlled symmetry were successfully assembled with nanometer precision, the relevant 3D plasmonic modes (i.e., artificial magnetism and magnetic-based Fano resonance) were fully rationalized by both numerical calculation and dark-field spectroscopy. This templating strategy for advancing AFM nanomanipulation can be generalized to exploit the fundamental understanding of various electromagnetic 3D couplings and can serve as the basis for the design of metamolecules, metafluids, and metamaterials.