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Simple Mod Turns Diodes Into Photon Counters

Posted by timothy on from the measure-once-vote-often dept.

KentuckyFC writes "The standard way to detect single photons is to use an avalanche photodiode in which a single photon can trigger an avalanche of current. These devices have an important drawback, however. They cannot distinguish the arrival of a single photon from the simultaneous arrival of two or more. But a team of physicists in the UK has found a simple mod that turns avalanche photodiodes into photon counters. They say that in the first instants after the avalanche forms, its current is proportional to the number of photons that have struck. All you have to do is measure it at this early stage. That's like turning a Fiat 500 into a Ferrari. Photon counting is one of the enabling technologies behind optical quantum computing. A number of schemes are known in which it is necessary to count the arrival of 0, 1 or 2 photons at specific detectors (abstract). With such a cheap detector now available (as well as decent photon guns), we could see dramatic progress in this field in the coming months."

7 of 118 comments (clear)

  1. Back in my day by UnknowingFool · · Score: 5, Funny

    You kids and your fancy diodes. Back in my day we counted photon by hand. Some people used paper to record the counts. We called them amateurs. Now get off my lawn!

    --
    Well, there's spam egg sausage and spam, that's not got much spam in it.
    1. Re:Back in my day by JustOK · · Score: 5, Funny

      I had to make photons on my first day and I saw it was good.

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      rewriting history since 2109
  2. Is it legal in Florida? by 140Mandak262Jamuna · · Score: 4, Funny

    I mean if multiple photons arrive at the same time at the detector should they be counted as a single vote or multiple votes? Whatever you say someone or the other would object and eventually it will be decided in the Supreme Court. Counting is quite weird in Florida.

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    sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
    1. Re:Is it legal in Florida? by JamesP · · Score: 5, Funny

      You see, it depends on the wavelength of the photon.

      If they are red they may be counted multiple times

      If they are blue, counting is more difficult, and sometimes several pass without being counted

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      how long until /. fixes commenting on Chrome?
  3. Re:Down already? by courteaudotbiz · · Score: 4, Funny
    1. Check your internet connection
    2. Post on slashdot that the site has been slashdotted ONLY if your internet connection was working on step one
  4. Re:Down already? by torkus · · Score: 4, Funny

    While I can get to the site...I have to question your logic.

    Unless /. has some new magics you generally can't post HERE without an active internet connection.

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    You can get rich if you own a politician, but you have to be rich to buy one in the first place.
  5. Re:Down already? by jddj · · Score: 4, Funny

    Actually, your attempt to read the site caused its superposition to decay into a site that's Slashdotted.

    About 50% of visitors from Slashdot will see the non-Slashdotted site.