Photon-separation to enhance the spatial resolution of pulsed STED microscopy

Stimulated emission depletion microscopy (STED) is one of the pivotal super-resolution techniques. It overcomes the spatial resolution limit imposed by the diffraction by using an additional laser beam, the STED beam, intensity of which is directly related to the achievable resolution. Despite reaching nanometer resolution, much effort in recent years has been devoted to reducing the STED beam intensity because it may lead to photo-damaging...