Improved microsphere-assisted super-resolution imaging by plasmon coupling

We propose a simple and effective method to improve the super-resolution imaging properties of a microsphere by combining plasmon coupling with the microsphere lens. Plasmon coupling can be excited when random silver nanoparticles are deposited on a self-assembled hexagonally closed-packed (hcp) SiO2 microsphere array. The electric field enhancement is found to be strongly influenced by plasmon coupling, and the enhanced near-field information of the samples can significantly affect the resolution quality. Using BaTiO3 glass (BTG) microsphere-assisted optical microscopy, we can clearly resolve a 200-nm-diameter hcp microsphere array when nanoparticle-nanoparticle plasmonic interactions and nanoparticle-thin film plasmonic interactions are excited. On the contrary, when there are no plasmon interactions excited, the 200-nm-diameter silver-coated hcp microsphere array is completely unresolved.