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

Representing light waves

  1. Aug 25, 2008 #1

    edguy99

    User Avatar
    Gold Member

    I am a computer programmer attempting to represent light rays travelling through the air, bumping into things, reflecting and refracting in some manner as they go through glass or other material.

    I have had good luck and the pictures look quite nice representing light photons as long skinny lines whose length is 1/2 the wavelength (ie Red 650 nanometer light is represented as a red line 325 nanometers long, but very, very skinny). They look like light rays that are commonly drawn in pictures. I can turn on a light and have them shoot all over the place.

    Regarding the issue of representing the photon as either a wave or a point as it travels though space. My question: Is there a reason that photons are not represented as long skinny rays or arrows with a start and end point that travel at the speed of light?

    Thank You
     
  2. jcsd
  3. Aug 28, 2008 #2
    I'm not sure if i understand your question. When you say 'represent' and 'pictures', are you referring to the way things are drawn in diagrams in textbooks or in some form of computer model.

    I would think that if you are modeling the classical properties of light (reflecting, refracting e.t.c.), you do not need to consider the particulate nature of light in your model. Photons may be represented as a little dot if you choose to but you still have to draw vectors showing which way they are travelling. A more common way of representing the photon is the wave-packet.

    http://www.cartage.org.lb/en/themes/sciences/Physics/QuantumPhysics/ParticlePhysics/pack.gif
     
  4. Aug 28, 2008 #3

    Andy Resnick

    User Avatar
    Science Advisor
    Education Advisor

    Ray optics, which is essentially what you are re-inventing, is another type of approximation for optical systems. Ray optics assumes that rays begin and end (and can be focused to) infinitesimal points. That is, diffraction is neglected. Typically, the trade-off comes by representing the angle that the ray makes with the optical axis as a sum (approximation to the sine function)- thus, there is first-order ray optics, (sin x ~x), third order, fifth, etc.
     
  5. Aug 28, 2008 #4

    edguy99

    User Avatar
    Gold Member

    Diagrams and models. The better the objects reflect the underlying physics, the more useful and understandable they are, especially in a simulation where they move around and you have to keep track of things over time. Gravity simulations are easy to do and they "look and feel" real since they follow the laws of physics.

    Thank you for the sample.


    Also, thanks for the hint on ray optics and diffraction. Do you know of any good reference material on the subject?
     
  6. Aug 29, 2008 #5

    Andy Resnick

    User Avatar
    Science Advisor
    Education Advisor

    The standard handbook (available on line, for free) is the MIL-HDBK-141. It's the US military handbook for optical design and covers all the details. This is the link I have:

    http://www.azmackes.net/astronomy/mil_hdbk_141/

    But the site is acting up, not sure if it's gone for good.

    There's also a lot of ray tracing programs out there- Zemax, Code V, OSLO, etc. Their website may have some FAQ type information available for you.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Representing light waves
  1. Light waves (Replies: 13)

  2. Light as a wave? (Replies: 12)

  3. Light as a wave (Replies: 22)

Loading...