The video demonstrates how the coupling of quantum emitters, such as single nanoparticles, to an external electromagnetic field can be investigated. An experimental configuration is presented, which employs a tunable supercontinuum white-light laser as an excitation source. A grating monochromator facilitates the selection of one wavelength at a time as well as its guidance to a confocal fluorescence microscope. After an isolated emitter is localized by raster scanning, a highly diluted sample prepared on a glass cover slip can be individually addressed and its excitation spectrum can be recorded. This allows for the detection of previously concealed quantum properties. Furthermore, the technique can be applied to sensitively study complex energy-migration processes in biological systems.