I have wanted to do a recreation of the classic quantum mechanics demo that show single photons
going through a dual slit can create a classic interference pattern.
Making the set-up did take some time but was reasonably straightforward. The source was a low power HeNe laser.
It goes through a rotatable variable attenuator and two fixed attentuators and then hits the dual slit. At the output
of the slit is a dielectric bandpass filter at 633nm (improves signal to noise ratio) and then into the detector, an old
Hamamatsu image intensifier. The output of this goes into a low light CMOS video camera.
It was easy to see that the set-up worked buy using a camera to integrate the output of the video camera. But I
wanted to see the photon hits add up in real time. I tried a few astrophotography stacking programs but they did
not show real time stacking. After asking about real time stacking on an astro website I was pointed to SharpCap.
It turned out to do the job. After some help from Robin, the programmer of SharpCap I was able to get a good enough
output which I videoed using a Nikon DSLR. Stacking is not integrating but it does work.
As I kind of expected getting software to do the job was more time consuming and frustrating than the mechanical set-up.
Here is a link to my Flickr site showing the video along with my best attempt to narrate what is happening.
https://www.flickr.com/photos/8763834@N02/53334653284 It's kind of fun to do these experiments even though I am finding nothing new. This one was especially neat because
after all is said and done, I have no idea (nor does anyone else) how this can possibly happen. One photon at a time
and you get an interference pattern. Real magic...
Cheers.
