Quantum Multilateration: Subdiffraction Emitter Pair Localization Via Three Spatially Separate Hanbury Brown And Twiss Measurements

Typically, optical microscopy uses the wavelike properties of light to image a scene. However, photon arrival times provide more information about emitter properties than the classical intensity alone. Here we show that the Hanbury Brown and Twiss experiment (second-order correlation function) measures the relative brightness of two single-photon emitters. By combining the total number of detected photons with the zero-lag value of the correlation function, the positions and relative brightness of two emitters in two dimensions can be resolved from only three measurement positions: trilateration. This result is impossible to achieve on the basis of classical intensity measurements alone and represents a minimal demonstration of the advantage gained using quantum measurements over conventional classical microscopy. The effective point-spread function for imaging scales approximately as the inverse square root of the acquisition time.