Our stimulated emission depletion (STED) microscopy system is developed based on the continuous-wave (CW) STED microscope invented in Stefan Hell's lab. A 491-nm laser is used as the excitation laser and a 1-Watt 592-nm laser is used as the depletion laser. A vortex phase plate is placed in the STED path to transform the beam into a doughnut shape in order to deplete the fluorophores in the boundary of a diffraction-lmited spot. An avalanche photodiode is used for detection.
Two solid state lasers: blue: 491 nm; orange: 592 nm.
Doughnut-shaped STED laser minimizes the fluorescent area at the center.
