Fraunhofer Diffraction Pattern Ratio of Power Densities

[Charles Link]

Yes. The final answer will be $N^2 \sin^2(\frac{3 \pi}{2N})$.

 

[Charles Link]

@says Please let us know if you got the right answer.

 

[says]

Will do! I've attached my notes to this comment. Pages 12-16 discuss Fraunhofer diffraction and power densities in more detail, but it doesn't have the exact equation we were using.

 

[Charles Link]

Will do! I've attached my notes to this comment. Pages 12-16 discuss Fraunhofer diffraction and power densities in more detail, but it doesn't have the exact equation we were using.

The bottom of p.12 has the formula we used. (The $sinc^2(\pi a u)$ is the single slit diffraction factor and is equal to 1 for narrow slits). They define $u=\frac{\sin{\theta}}{\lambda}$ on p.3. I have seen presentations on the subject that are easier to follow. I would suggest the Optics book by Hecht and Zajac or Halliday-Resnick volume 2.

 

[Charles Link]

Additional note: Even though they have the formula we used on p.12, the notes do not explain any of the details of how to use that formula=i.e. by taking the limit as the denominator goes to zero, etc., for the primary maxima. $\\$ Diffraction theory is a topic that unless they present it with some care and some detail, you can easily get lost in mathematical detail. It really is not tremendously difficult, but it needs a thorough, and at the same time straightforward presentation.