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!

Beam divergence after a slit

  1. Sep 9, 2009 #1
    what is the effect of placing a slit of say one tenth of an inch infront of a laser beam (3 inch dia )with a divergence of say one degree upon the divergence of the emanating beam?(slit placed symmetrically along the beam axis) ? would the emanating beam also be of the same divergence ?
  2. jcsd
  3. Sep 10, 2009 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    The divergence angle would increase somewhat, but not appreciably in this case.

    For visible light, a 0.1" slit creates a diffraction angle of approximately (550 nm)/(0.1") = 2 x 10-4 radians or 0.01 degrees (ballpark figure)

    Since that's a lot smaller than the initial 1 degree divergence angle, the effect is pretty small for visible wavelengths.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook