Science
In reply to the discussion: Quantum Entanglement, Dark Counts, Coincidence Detection [View all]mindwalker_i
(4,407 posts)Yeah, I'm still working on it. The main problem is that I need to be able to finely position mirrors and laser beams in order to get the interference right. It's on'e thing to get an interference pattern with a Mach-Zehnder interferometer, but it's harder to get it interfering perfectly. So with that in mind, I am building nice little optic mounts with X, Y, and rotation adjustments. That's hard. The circuitry for interfacing a computer to the photon detectors was fairly easy, using some 74F chips for counters, and a PIC microcontroller for getting those counts back to the computer.
Once I can get some of these optic mounts done, I'll start working with the BBO to see how many entangled pairs it produces (pumped initially with a 405nm diode from ebay, but I may need to upgrade that to a lab laser). What I don't know is how coherent the downconverted photons will be, which will effect whether the interferometer works. Another possibility will be to use a double slit. I think that will be more immune to coherence issues, but a lot of photons will be lost between the slits.