Quantum limited superresolution - imaging beyond the Rayleigh diffraction limit

Conventional super-resolution of closely spaced point sources using image intensity data acquired by noiseless single-photon detectors suffers from Rayleigh's diffraction curse that can only be overcome at photon numbers that scale quartically with the degree of required super-resolution. By contrast, acquiring and processing suitably chosen mode projections of the wavefront, which contain dual information of its intensity and phase, can reduce the photon budget to one that is quadratic in the degree of super-resolution and achieve quantum-limited performance. Such dramatic improvements enabled by the wavefront projection (WFP) approach have been realized both in computer simulation and laboratory experiments over the last five years. This paper will explore the fundamental, theoretically insuperable limits on super-resolution imaging by presenting computations of quantum Fisher information and practical realizations of the novel WFP approach that can reach these limits for a variety of point and extended source geometries and operating conditions.