PHOTON NOISE-REDUCTION BY CONTROLLED DELETION TECHNIQUES

We analyze different mechanisms for the generation of sub-Poissonian light beams within the framework of a simple photon model. In this model light is treated as a stream of discrete photon events that are localized in time. The course taken by each of these photons from its generation to its detection is evaluated according to the outcomes of several branching processes. We consider mechanisms in which the reduction of intensity noise below the shot-noise level is effected through control of photon deletion probabilities, both in a feedback configuration involving a single light beam and in a feedforward configuration involving twin light beams for which we explicitly include decorrelations. The resultant intensity noise spectra are evaluated analytically as well as numerically by Monte Carlo simulation. These results are compared with some corresponding results obtained from a semiclassical input-output analysis.