Advances in STED Nanoscopy

Fluorescence microscopy is one of the most powerful tools in science and allows noninvasive characterization of a sample with high sensitivity and specificity. For a long time, however, details smaller than half the wavelength of light (∼200 nm) could not be resolved by using a conventional light microscope. Recently, to break diffraction barrier, researchers have demonstrated various super-resolution approaches, such as stimulated emission depletion (STED) microscopy, to a resolution of better than 20 nm. This review describes the principles and the features of STED microscopy, and its current advanced applications to physics, chemistry, material science and biology.