An interference experiment with light beams modulated in anti-phase by an electro-optic shutter

An interference experiment is described in which measurements are made of fringe-visibility when the interfering light beams are amplitude-modulated in anti-phase. The conditions were such that (i) the mean density of quanta in the interferometer contributing to the interference was much less than unity; (ii) the electro-optic shutters were switched several times between the detection of successive quanta.