Nonfluorescent Optical Probing of Single Molecules and Nanoparticles

Abstract

Notwithstanding its unique power for imaging and investigation of transparent condensed and biological matter, fluorescence presents severe limitations: it requires special fluorescent labels, which are prone to photobleaching, and the photon streams it provides are relatively weak. In the past 10 to 20 years nonfluorescent optical methods have appeared, which can also provide information on matter at the nanoscale, while presenting different limitations. In the present paper, we review some of these methods, with special emphasis on work from our group. We consider mostly the optical detection and study of single immobilized or transiently bound molecules and nanoparticles through their scattering, the heat they dissipate in the environment upon light absorption, or their coupling to auxiliary optical resonators such as whispering-gallery modes.