Accurate Transfer of Individual Nanoparticles onto Single Photonic Nanostrusctures*

Controlled integration of metallic nanoparticles (NPs) onto photonic nanostructures enables realization of complex devices for extreme light confinement and enhanced light-matter interaction. However, metallic NPs are usually deposited via drop-casting, which prevents their accurate positioning. In our work, we present a reproducible, single-step, and cost-effective method for the controlled nanopositioning of single metallic NPs. This methodology can be used for both the parallel printing as well as the single positioning of individual NPs onto lithographically fabricated nanostructures with sub-micron accuracy in one single step. It is based on soft lithography printing that employs elastomeric stamp-assisted transfer. Taking advantage of the capillary forces in the elastomeric stamps and a custom-built µ-positioning system, we achieve a single-step single NP transfer yield of up to 28% in a matrix of more than 2300 photonic resonators. This large-scale approach opens the path towards deterministic Nanoparticle-on-a-mirror (NPoM) fabricated cavities on nanophotonic structures – such as nanoantennas or waveguides - for advanced spectroscopic architectures on-a-chip, showing the potential of building complex photonic nanodevices for applications ranging from enhanced sensing and spectroscopy to signal processing.