Fundamental precision limits of optical fluorescence microscopy

Seminar author:Matteo Rosati

Event date and time:11/14/2023 04:00:pm

Event location:

Event contact:

In the past years, optical fluorescence microscopy (OFM) has made steady progress towards increasing the localisation precision of fluorescent emitters in biological samples. The high precision achieved by these techniques has prompted new claims, whose rigorous validation is an outstanding problem.
For this purpose, local estimation theory has emerged as the most used mathematical tool. Our work provides a rigorous analysis of OFM techniques from the perspective of classical and quantum estimation theory.

Firstly, we establish a multi-parameter estimation framework that captures the full complexity of single-emitter localisation in an OFM experiment. Our framework relies on the fact that there are other unknown parameters alongside the emitter’s coordinates, such as the average number of photons emitted (brightness) and background noise, that are correlated to the emitter position, and affect the localisation precision.
We showcase our method with MINFLUX [1] microscopy, the OFM approach that nowadays generates images with the best resolution. At variance with previous works, we show that the localization precision cannot be increased arbitrarily by reducing the beam separation, thus in a sense re-establishing the diffraction limit [2].

Secondly, we analyse the problem of resolving two fluorescent emitters from a fully quantum perspective. We establish the fundamental quantum resolution limits of OFM, studying how the celebrated super-resolution result of Tsang et al.[2] is affected in a setting where the relative brilliance of the two sources depends on their relative distance. This result highlights the potential of engineering the input radiation, rather than the output measurement. [1] Francisco Balzarotti et al., “Nanometer resolution imaging and tracking of fluorescent molecules with minimal photon fluxes”. In: Science (80-. ). 355.6325 (Feb. 2017), pp. 606–612[2] Matteo Rosati et al., “

Fundamental precision limits of fluorescence microscopy: a new perspective on MINFLUX”, arXiv:2306.16158.[3] Mankei Tsang et al., “Quantum theory of superresolution for two incoherent optical point sources”. In: Phys. Rev. X 6.3 (Aug. 2016), p. 031033.