Axial superlocalization with vortex beams

Improving axial resolution is paramount importance for three-dimensional optical imaging systems. Here, we investigate the ultimate precision in axial localization using vortex beams. For Laguerre-Gauss (LG) beams, this limit can be achieved with just an intensity scan. The same is not true for superpositions of LG beams, in particular for those with intensity profiles that rotate on defocusing. Microscopy methods based on rotating vortex beams may thus benefit from replacing traditional intensity sensors with advanced mode-sorting techniques.

Automated summary

Improving axial resolution is crucial for three-dimensional optical imaging systems, and using vortex beams can achieve ultimate precision in axial localization. While this limit can be reached with just an intensity scan for Laguerre-Gauss beams, it is not the case for superpositions of such beams. Microscopy methods based on rotating vortex beams may benefit from advanced mode-sorting techniques replacing traditional intensity sensors.