• Photo Diffraction Phenomenon
• Two-photon Diffraction And Quantum Lithography
• Photon Diffraction Electron

Double slit interference pattern

Interference experiments with only one photon in the experiment at a time have also showed interference patterns. A previous paper that studied photon diffraction and interference (IntellectualArchive, Vol.1, No. 20, ISSN 1929-4700, Toronto, July 2012.) required several photons in the experiment at the same time. Photon diffraction or nanoscopic diffration occurs only with photons.

Photo Diffraction Phenomenon

For the movie shown below, the baffle has been moved to expose both slits. During the movie, the scanning slit is moved across the interference pattern.

The still at left shows the single slit diffraction pattern. The second screen movie shows the PMT output as the scanning slit is moved across the two slit interference pattern at approximately constant speed.

Two-photon Diffraction And Quantum Lithography

In this movie, we can both see and hear maxima and minima in the rate of arrival of photons at the PMT. The result shows the combination of diffraction and interference: a classic pattern for a two-slit Young's experiment. (For those who have noticed that the spacing between the peaks is not exactly equal: the answer is that the micrometer is moved by hand. The oscilloscope trace moves with constant speed and, if the micrometer speed were constant, this would mean that position on the oscilloscope screen is linear related to position on the interference pattern.I tried to keep the scanning speed constant by turning equal amounts in a regular rhythm, but the former is hard to achieve with precision.)

Photon Diffraction Electron

How to interpret this pattern? The oscilloscope trace in this experiment is a histogram of photon arrivals as a function of position across the 'screen'. So the interference term – the (cos ²φ/2) term determines the probability of photon arrival at any point. The square of the amplitude of the sum of the wave amplitudes determines the probability of photon arrival. Further, as we'll see later, a similar conclusion applies to electron behaviour.