We have developed and experimentally realized a new method for achieving super resolution in imaging.
In this new work, published in Physical Review Letters, we have devised an extremely simple scheme to beat the standard phase Rayleigh limit without the use of complex NOON states.
Phase resolution plays an important role in many sciences including metrology, lithography and microscopy. The classical resolution limit is due to Lord Rayleigh and is known as Rayleigh diffraction limit in resolution. Going beyond the Rayleigh resolution limit is known as super resolution. Super resolution has been achieved in several experiments employing highly non-classical states (so-called NOON states) or highly complex detectors.
Against common wisdom, we have shown that one does not need any non-classicality in the setup – neither in preparation nor in detection to obtain deterministic super phase resolution! We have proposed and experimentally realized a new method that strongly beats Rayleigh’s resolution limit by using a simple scheme. It is based on coherent states of light (from a standard laser), intensity detectors and a novel binning protocol. The improvement with respect to the Rayleigh criterion goes with √N where N is the number of photons in the coherent state. The photon number of a coherent state can easily be made very large, and thus an extremely strong improvement can be observed.
In the figure below, the dashed line represents the standard Rayleigh limit while the red dots are the experimental results from the experiment. As the blue line is much narrower than the dashed line, super resolution is achieved.
