Optical Signatures of Small Nanoparticles in a Conventional Microscope

Optical signatures (see left of image) are generated in a carefully adjusted optical microscope for single gold particles (center of image, at cross-hairs) of diameter as small as 3 nm. The three-dimensional nature of the signatures is shown by z stacks (right of image, at one-quarter scale) and provides the potential for locating, sizing and tracking particles in a conventional optical microscope with applications in nanoengineering and nanobiotechnology.