Missing light signals the presence of a nanoparticle

Seemingly identical nanoobjects such as molecules, proteins, or nanoparticles differ in size, shape, and local environment. Averaging over many nanoobjects blurs the result one gets. Only measurements on single nanoobjects give the full picture. Optical spectroscopy of a single absorbing nanoparticle has to detect a small variation on a large, noisy background. Coupling the particle under investigation to a larger antenna particle simplifies the task and will allow experiments on tiny nanoparticles.