Tuesday 18 February 2020

optics - Can single photons make a hologram over time


INTRO. In the parallel slit experiment, single photons ejected from the source at different times still seem to interfere to make a fringe pattern, which in a sufficientliy long exposure time becomes identical to that made by a continuous coherent light source (particle/wawe duality). Holograms are usually made having a continuos laser beam illuminating an object, the image of which is seen by a photographic film. At the same time the film is exposed to a non-diffracted refererence beam of the same frequency but directed at another (fixed) angle so as to form an interference pattern with the object beam. The pattern is recorded on the film as a hologram.


EXPERIMENT. Now suppose we somehow can produce a single photon which "bounces off" the object and "hits" the extremely sensitive film producing a first "object image". Some random time later, we produce another single photon of exactly the same frequency, which we direct at a fixed angle towards the film producing a faint "reference exposure". If we repeat this process umpty-billions of times one should think - in analogy to the double slit experiment - that over time the film will contain the same hologram of the object as if continuos beams were used.


QUESTION. Is this assumption correct, and if so how can it be proved (or disproved)?





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