Sub-Poissonian Photoelectron Statistics Produced Using Parametric Down-Conversion with Feedback

Sub-Poissonian photoelectron statistics have been produced by using the detection of down-converted photons in a trigger channel, having an electronic dead time, fed back to gate conjugate photoelectrons in a signal channel. With suitable choice of gate width and dead time a second factorial moment of the photo-electron count distribution as low as 0.4 has been achieved with considerable improvements in signal variance over equivalent Poisson sources. Suitable modification of the apparatus to produce sub-Poissonian photons rather than photoelectrons is described.