Researchers have discovered how the geometry of gold nanoparticles affects their images. Gold nanoparticles can be imaged optically and their movements can be seen using a technique known as differential interference contrast (DIC) microscopy. How gold nanoparticles appear in these images depends upon their environment. This can be used to learn about time-dependent nanoscale processes. However, an outstanding question has been whether or not the geometry of the gold particles affects how they are imaged. Researchers looked at three common nanoparticle geometries: a single rod, two rods stuck together and two rods separated but close to each other, so-called proximate rods. Trapping differently positioned nanoparticles and characterizing them with an electron microscope enabled comparison with the DIC images to see how each geometry is imaged in the optical system. Unlike other techniques, DIC produces images that uniquely distinguish these different geometries to even as they move around. Even at the nanoscale, geometry matters.
Influence of Gold Nanorod Geometry on Optical Response