  The ultimate sensitivity of optical measurements is a key element of many
recent works. Classically, it is mainly limited by the shot noise limit.
However, a measurement setup that incorporates quantum mechanical principles
can surpass the shot noise limit and reach the Heisenberg limit. Nevertheless,
many of those experiments fail to break even the classical shot-noise limit.
Following a recent proposal, we present here the results of optical phase
measurements with a photon-number resolving detector using coherent states of
up to 4200 photons on average. An additional scheme that can be implemented
using standard single-photon detectors is also presented, and the results of
the two schemes are compared. These measurements present deterministic
single-shot sub-wavelength super-resolution up to 288 better than the optical
wavelength. The results follow the classically limited sensitivity, up to 86
times better than the wavelength.
