Close
  Indian J Med Microbiol
 

Figure 7: (a) The process of stimulated emission. A ground state (S0) fluorophore can absorb a photon from excitation light and jump to the excited state (S1). Spontaneous fluorescence emission brings the fluorophore back to the ground state. Stimulated emission happens when the excited-state fluorophore encounters another photon with a wavelength comparable to the energy difference between the ground and excited state. (b) Schematic drawing of a STED microscope. The excitation laser and STED laser are combined and focused into the sample through the objective. A phase mask is placed in the light path of the STED laser to create a specific pattern at the objective focal point. (c) In the xy mode, a donut-shaped STED laser is applied with the zero point overlapped with the maximum of the excitation laser focus. With saturated depletion, fluorescence from regions near the zero point is suppressed, leading to a decreased size of the effective PSF. (Reproduced with permission from reference 4.)

Figure 7: (a) The process of stimulated emission. A ground state (S0) fluorophore can absorb a photon from excitation light and jump to the excited state (S1). Spontaneous fluorescence emission brings the fluorophore back to the ground state. Stimulated emission happens when the excited-state fluorophore encounters another photon with a wavelength comparable to the energy difference between the ground and excited state. (b) Schematic drawing of a STED microscope. The excitation laser and STED laser are combined and focused into the sample through the objective. A phase mask is placed in the light path of the STED laser to create a specific pattern at the objective focal point. (c) In the xy mode, a donut-shaped STED laser is applied with the zero point overlapped with the maximum of the excitation laser focus. With saturated depletion, fluorescence from regions near the zero point is suppressed, leading to a decreased size of the effective PSF. (Reproduced with permission from reference 4.)