Plasmonic nanocore in a water microdroplet with optical vortex

Plasmonic nanostructures enable us to enhance light fields at nanoscale beyond diffraction limit, thereby offering us metamaterials and plasmonic crystals to realize exotic light-matter interactions, including negative refractive index, invisible cloaking, and perfect absorption. We here demonstrate, for the first time to be the best of our knowledge, the creation of a single water microdroplet with a single plasmonic Au nanoparticle (~150 nm) core (plasmonic nanocore) by employing the optical vortex induced forward transfer. The microdroplet can be easily trapped to form a single plasmonic nanocore on a receiver substrate with a spatial resolution beyond the diffraction limit. Going beyond conventional fabrication processes for plasmonic structures, such as lithography technologies based on electron and ion beams, such plasmonic nanocore formation in a water microdroplet should offer us new fabrication technology for plasmonic structures.