A sample substrate adapted for use with electromagnetic excitation light includes a base and a layer system. The layer system includes a multilayer interference coating with at least two layers wherein the thicknesses of the layers ensure that light emitted by a fluorescent sample material disposed on top of said multilayer interference coating is reflected. Light directed to a fluorescent sample material disposed on the substrate causes light to be emitted from the sample. The layer system includes a multilayer interference coating with at least two layers wherein thicknesses of the layers cause separation of the excitation light from the emitted light.