Nano-Optics with Plasmons

Gold and silver nanoparticles show an interessting color effect in the visible specral region. They act as tiny nano antenna for light and scatter it very effectively.  We use this effect in a new way to investigate single biomolekules (see research). Below is an example of gold and silver particles in a dark-field microscope. Every point is a single nanoparticle. The picture shows in real colors realistically the impression of the naked eye when one looks into such a microscope. The color indicates the shape and material composition of the particle.