Which mechanism limits attainable spatial resolution in stimulated emission depletion (STED) microscopy?

💡 Explanation

When the depletion beam intensely illuminates a sample, photobleaching occurs because fluorophore molecules undergo irreversible photochemical reactions, limiting the number of photons that can be emitted without damage, degrading image resolution. Therefore photobleaching limits resolution, rather than diffraction, expansion or quenching, which are separate artifacts.

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