The universal scaling laws that determine the achievable resolution in different schemes for super-resolution imaging

The resolution limits of popular sub-diffraction and sub-wavelength imaging schemes are examined using a unified approach that allows rapid comparison of the relative merits and shortcomings of each technique. This is intended to clarify the often confusing and constantly growing array of super-resolution techniques. Specific techniques examined include centroid-based techniques like PALM (photo-activated localization microscopy) and STORM (stochastic optical reconstruction microscopy), structured illumination techniques like SSIM (spatially structured illumination microscopy), STED (stimulated emission depletion), and GSD (ground state depletion), coherent techniques like MRI (magnetic resonance imaging), Rabi gradients, and light shift gradients, as well as quantum-inspired multi-photon techniques. It is found that the ultimate resolution for all these techniques can be described using a simple ratio of an oscillation frequency to an effective decay rate, which can be physically interpreted as the number of oscillations that can be observed before decay (i.e. the quality factor Q of the imaging transition).