This lecture covers the principles and applications of Super Resolution Microscopy, focusing on the Stimulated Emission Depletion (STED) method. It explains the key parameters and optimization techniques for achieving high-resolution imaging, including the role of STED laser intensity and saturation intensity of the fluorophore. The instructor discusses the non-linear dependence of the depleted population of excited electrons on the STED laser beam intensity, leading to super-resolution imaging. Examples of suitable dyes and lasers for STED imaging are provided, along with the resolution factors and limitations of STED microscopy.