The noise-limited-resolution for stimulated emission depletion microscopy

TL;DR

This paper analyzes the fundamental noise limits of STED microscopy in diffusive regimes, revealing that resolution is constrained by thermal motion and photon statistics rather than saturation intensity.

Contribution

It provides a theoretical analysis showing that, under diffusion, STED resolution depends on thermal motion and photon count, not on fluorescent saturation intensity.

Findings

Resolution limited by thermal motion and photon count

Noise-limited resolution independent of saturation intensity

Thermal motion constrains signal integration time

Abstract

With recent developments in microscopy, such as stimulated emission depletion (STED) microscopy, far-field imaging at resolutions better than the diffraction limit is now a commercially available technique. Here, we show that, in the special case of a diffusive regime, the noise-limited resolution of STED imaging is independent of the saturation intensity of the fluorescent label. Thermal motion limits the signal integration time, which, for a given excited-state lifetime, limits the total number of photons available for detection.