(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

I'm choosing an angle for a diffraction grating such that a laser of particular wavelength λ is retroreflected (reflected back along incident path).

2. Relevant equations

If you have a better way than using the equation below, feel free to explain. The book that I'm looking through treats the blazed diffraction grating as a set of N slits. This results in the equation

I(θ)=[itex]\frac{I(0)}{N2}(sinc(β)^{2})(\frac{sin(Nα)}{sin(α)})^{2}[/itex]

where β=(kb/2)sin(θ) and α=(ka/2)sin(θ) with b=length of slit and a=distance between center of two adjacent slits

k is the wavenumber(I think).

3. The attempt at a solution

What I'm looking for is a kick in the right direction. I'm not sure how this equation helps me. I don't know how to use k and and I don't really know a or b (although I could calculate them). I'm not sure how N^2 comes into play since I don't know the total number of slits on the grating. Also I don't know why the total number of slits should play much of a role when the laser is incident on only a tiny portion of the grating. I think there is something fundamental that I'm not understanding. Obviously I want the intensity to be maximized along retroreflected path. Any help would be great. Thank you.

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# Homework Help: Diffraction Grating Angles

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