Chemical activation Electric excitation Electromagnetic fields Fluorescence Fluorescence microscopy Isomers Laser excitation Light Molecules Nanoparticles Nanostructures Photochromes Photochromic transformations Photochromism Plasmons Refractive index Silver Single-molecule fluorescence microscopy Single-molecule studies Stochastic systems Surface plasmons TIRFM Total internal reflection fluorescence microscopy Visible light excitation nanoparticles photochromes surface plasmon