  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
intensity asymmetry of two single photon emitters, and that 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, a result that is impossible to achieve on the basis of intensity
measurements alone.
