Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Shape of EM waves

  1. Aug 15, 2003 #1


    User Avatar

    There are many properties of EM Waves that can be seen as some kind of ordered distribution of energy in space and time. I can think of a few:

    - Polarization: Direction of the electric field in space.
    - Coherence: Some kind of phase relationship

    My questions are:
    - How does a single photon travel? Is a single photon always polarized?, ie, is the electric field of a photon always in a single direction, does it rotate with time and travel in like a helix or does the orientation of the electric field just a probability?

    - Is the electric field in phase with the magnetic field? I found contradicting info on this. See http://www.play-hookey.com/optics/transverse_electromagnetic_wave.html [Broken]

    Thanks you.

    Last edited by a moderator: May 1, 2017
  2. jcsd
  3. Aug 15, 2003 #2
    Isn't there a difference between a photon and an electromagnetic wave? I thought a photon was simply a massless(invariant mass)particle that carries energy which is equal to Plank's Constant times the frequency of the CORRESPONDING ELECTROMAGNETIC WAVE, and that this particle also carries momentum which is equal to it's energy divided by c, and that an electromagnetic wave's energy was spread through out the whole wave which is made oscillating electric and magnetic fields. The photon isn't made of an oscillating electromagnetic field, is it?
  4. Aug 15, 2003 #3


    User Avatar

    Nope, EM wave and photons are the different sides of the same entity of Electromagnetic radiation, AKA light.

    Also, my knowledge of QM is rusty on this, but as far as quantum theory exists, we don't know the way in which photons travel between observation as a matter of quantum uncertainty. We know that it is represented by a probabilistic wave function that gives how likely it is to appear in a certain place, which then collapses down to whatever we detect upon measurement.
  5. Aug 15, 2003 #4
    Would what we think as an electromagnetic wave be similar to the probabilistic wave function that each photon has when unobserved?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook