Size tunable passive cloaking platform using self-assembled plasmonic nanostructures. Imran Khan,¹ Arnold Kim,² and Sayantani Ghosh¹ ¹Department of Physics, University of California, Merced, CA 95343 USA ²Department of Applied Mathematics, Univ

Plasmonic cloaking works by suppressing dominant scattering harmonics radiated from the cloaked object. A shell made of plasmonic nanoparticles (NPs), in combination with the cloaked object as a core, creates the complete plasmonic cloaking structure. In this study, we present the design and fabrication of spherical nano- to micron-scale shell structures via molecular self-assembly of gold NPs, with the goal of reduced scattering and therefore, cloaking, in the VIS-NIR spectral range. Scattering suppression range is varied by tuning the critical parameters of the effective medium, such as core to shell radius ratio and the filling fraction of the NPs in the shell wall. In addition to experimental work, we have also developed a multiscale simulation platform that explicitly models multiple scattering by the gold NPs and their multiple interactions with the core. Simulation results shows that the nano-assembled spheres yield suppressed visibility in the desired spectral range.