Abstract

The phase of interference fringes identifies with their position, and since we can measure the position of individual photons we can measure their individual phases. Estimating average fringe parameter information requires at least three detector channels to sort out the three parameters of brightness, contrast, and phase. A convenient Young’s fringe interferometer with a lenticular receiver and simple digital circuitry is demonstrated for displaying efficient ratiometric phasor diagrams in real time from discrete photons. A series of high-speed circuits that require no analog switching are also presented for resolving phase from somewhat brighter signals to four, six, or even 256 sectors per fringe at multimegahertz sampling rates. In all cases the digital format is suitable for real-time recursive phase unwrapping and averaging by using a read-only memory and multiplier-accumulator to implement the polar innovations filter.

© 1988 Optical Society of America