1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Photon Detectors

  1. Jan 19, 2012 #1
    Do photon detectors necessarily need to absorb the photon to detect it (i.e. can photon detectors exist that make the detection but allow us to perform further tests on the photon)?
  2. jcsd
  3. Jan 20, 2012 #2


    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    "photon Detectors" aka Photomultiplier tubes work on the principal of the photon(s) striking an electrode which emits electrons which strike other electrodes emitting more electrons in a cascading effect, producing a measurable current flow, the "photoelectric effect" first discovered by Heinrich Hertz in the late 1800's and was followed up by work done by Elster and Geite.

    I personally am unaware of any photon detectors that work the way you describe, maybe some one else will chime in with that possibility :)

  4. Jan 20, 2012 #3

    Vanadium 50

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor
    2017 Award

    A detector is changed by the photon, and the photon (if it still exists) is changed by the detector. This is a statement that does not depend on the details of the detection mechanism.

    You can only step in the same stream once.
  5. Jan 20, 2012 #4


    Staff: Mentor

    You might be interested in so-called "weak measurement". I don't know much about it, but you clearly have an internet connection :smile:
  6. Jan 20, 2012 #5
    Might be possible via Quantum Non demolition measurement

    Chk this article out
    "Quantum non-demolition measurement allows physicists to count photons without destroying them"
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook