Anti-Reflectivity


When light of intensity I reflects from a surface separating two media with refractive index n1 and n2, the intensity of the reflected light is
(n2-n1)2/(n2+n1)2 .

To make reflection zero a thin layer of a material of refractive index n of thickness t is inserted between the two media. Give me the value of n and t such that light of wavelength λ is not reflected at all.

7 comments:

  1. Pulkit MendirattaDecember 21, 2011 at 6:02 PM

    t=λ/4n ?

    ReplyDelete
  2. AnujDecember 21, 2011 at 6:43 PM

    i don't know how to solve this but you have to express n and t in terms of n1 and n2.

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  3. ShivankerDecember 21, 2011 at 9:13 PM

    @Pulkit: well.. okay.. :|

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  4. ShivankerDecember 22, 2011 at 7:58 PM

    anyone for n ??

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  5. ShivankerDecember 22, 2011 at 8:06 PM

    by the way, for t its t = λ/4n * (2m+1) where m is a non-negative integer.. (though the most preferable is λ/4n :P )

    a hint for n... take reflection coeff. to be (n1-n2)/(n1+n2) and transmission coeff. to be 2*n1/(n1+n2)

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  6. AbhishekDecember 23, 2011 at 7:02 PM

    how to proceed ?

    ReplyDelete
  7. ShivankerDecember 24, 2011 at 6:55 AM

    here's the solution
    http://shivankergoel.blogspot.com/2011/12/anti-reflection-coatings.html

    ReplyDelete

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