Three-channel spectrometer for wide-field imaging of anisotropic plasmonic nanoparticles

A three-channel spectrometer (3CS) based on a commercial digital camera was developed to distinguish among tens of large (>100 nm), anisotropic plasmonic particles with various shapes, orientations, and compositions on a surface simultaneously. Using band-pass filters and polarizers, we could enhance the contrast of 3CS images to identify specific orientation and composition characteristics of gold and gold–silver nanopyramids as well as the direction of the longest arm of gold nanostars.