Super-resolution imaging of plasmonic nanostructures by microsphere-assisted microscopy.

We fabricate both triangularly and circularly shaped Au, Ag, and Cr nanoparticle arrays and observe the imaging properties of these plasmonic nanostructures by glass (BTG) microsphere-assisted microscopy. We experimentally find that the resolution of triangularly shaped Ag nanoparticle arrays is higher than that of Au and Cr ones, and a gap resolution of ∼/7.7 is demonstrated for the circularly shaped Au, Ag, and Cr nanostructures.

Direct observation Brownian motion of individual nanoparticles in water using microsphere-assisted microscopy.

Observing Brownian motion of nanoscale objects through a traditional optical microscope is still a challenge. Here, we present a method to overcome this challenge by using a traditional optical microscope assisted with a removable microsphere-embedded thin film. The diffusion coefficient of individual unconstrained polystyrene (PS) nanoparticles with a diameter of 300 nm in water is calculated from their respective mean-square displacement versus time curves, and the measured diffusion coefficient shows good agreement with the theoretical Stokes-Einstein one, proving the feasibility of our method.