Fluorescence depletion mechanisms in super-resolving STED microscopy

• DOI: 10.1016/j.cplett.2007.06.017
• Publication Date: 2007-06-11T13:04:30Z
• Authors: E. Rittweger; B.R. Rankin; V. Westphal; S.W. Hell
• Keywords: 02 engineering and technology; 0210 nano-technology

We prove that stimulated emission is by far the dominant quenching mechanism for providing super-resolution in fluorescence microscopy with a red-shifted depletion beam. Our evidences are based on simultaneously measuring fluorescence quenching and photon gain in the quenching beam. Measurements were performed for several fluorescent dyes including fluorescent proteins over a wide spectral range of their emission spectra. We found that, for each fluorophore, the wavelength dependence of both signals closely follows that of the stimulated emission cross-section.