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What are the two requirements for an anti-reflection coating?

  1. Jun 25, 2013 #1
    1. The problem statement, all variables and given/known data
    What are the two requirements for an anti-reflection coating?

    2. Relevant equations
    Not sure there are any.

    3. The attempt at a solution
    I googled the term anti-reflection coating and I found a wikipedia article on it here. http://en.wikipedia.org/wiki/Anti-reflective_coating

    From what I read, I'm not sure what the "requirements" would be. The only thing I found that might hint at what the answer should be is "Many coatings consist of transparent thin film structures with alternating layers of contrasting refractive index." Can anyone help out with this, or clarify what the requirements could be? This is for an electromagnetic fields course if that gives any more of a direction as to what I should be looking for.
  2. jcsd
  3. Jun 26, 2013 #2

    Simon Bridge

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    Welcome to PF;
    What is an anti-reflective coating supposed to acheive and how do they normally do this?
    Translate that into properties and you have your answer... probably you should have a look at your recent course notes for ideas.
  4. Jun 26, 2013 #3
    Well the ultimate goal of them is to reduce reflection which will maximize the amount of light transmitted into a surface (ex. glass). From what I read online this is done by destructive interference. Could you explain what you mean by properties?

    Sorry, I would love to review my course notes, but the professor had already removed the course notes for the course and I am redoing a homework set to receive more points so I have nothing to reference from. Any more help in pointing me in the right direction would be appreciated. Thank you.
  5. Jun 27, 2013 #4
    Haven't you already listed one property already - the property of increasing the transmission of light through the lens.
  6. Jun 27, 2013 #5

    Simon Bridge

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    That's two properties - well done.

    Material properties like refractive index, shape, color, size, smell, texture.... what would be the important properties for an anti-reflective coating?

    I see ... by "course notes" I meant the ones you wrote down yourself, not the ones your prof posted online. The reason he removed them because you are expected to have your own by now.

    Google for "thin films".
    The coating will have two surfaces.
    Light is reflected off both surfaces.
    If the light reflected from the bottom surface destructively interferes with the light from the top surface, then there will be no reflection.
    What is the condition for destructive interference?
    What material properties of the film need to be taken into account?
    i.e. is the wavelength of the light the same inside the film as on either side of it?
    Last edited: Jun 28, 2013
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