1. Not finding help here? Sign up for a free 30min 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!

Anti-reflective coating optimum index of refraction

  1. Mar 12, 2007 #1
    Hello

    I'm trying to solve a problem where i'm asked to find the optimum index of refraction for an antireflective coating on a piece of glass. In trying to derive an equation for it I keep coming across this in the internet (where 1,0, and s should be subscripts)

    n1=sqrt(n0ns)

    where n1 is the index of refraction of the coating, n0 is that of the air, and ns is the glass (see here - http://en.wikipedia.org/wiki/Antireflection_coating). I can't work out how this was derived for the life of me and can't find it anywhere in books or the internet. Does anyone have any ideas?

    Thanks a lot

    Robert
     
  2. jcsd
  3. May 23, 2007 #2
    I also have found this near impossible, despite spending hours working on it. My books quote that the relation given above should give zero reflection, but the only way I can make that happen is if n0 = ns.

    I understand theoretically how and why this should work, I just can't get it to work mathematically..
     
  4. May 23, 2007 #3
    @reb30:

    I don't know if you own a copy of the textbook "Optics" by Hecht's but there's a derivation on page 375. Unfortuanatly it's very complicated and is done for general angle of incidence, rather than normal incidence. I couldn't make it work for simplified start conditions..
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?