Sharper low-power STED nanoscopy by time gating

Applying pulsed excitation together with time-gated detection improves the fluorescence on-off contrast in continuous-wave stimulated emission depletion (CW-STED) microscopy, thus revealing finer details in fixed and living cells using moderate light intensities. This method also enables super-resolution fluorescence correlation spectroscopy with CW-STED beams, as demonstrated by quantifying the dynamics of labeled lipid molecules in the plasma membrane of living cells.