All Problems

Diffraction of Light

Problem 5.104

A plane light wave with wavelength \(\lambda\) and intensity \(I_{0}\) falls normally on a large glass plate whose opposite side serves as an opaque screen with a round aperture equal to the first Fresnel zone for the observation point \(P .\) In the middle of the aperture there is a round recess equal to half the Fresnel zone. What must the depth \(h\) of that recess be for the intensity of light at the point \(P\) to be the highest? What is this intensity equal to?

Reveal Answer
 5.104. h=λ(k+3/4)/(n−1), where k=0,1,2,…, (b) Imax⁡≈8I0\begin{aligned} &\text { 5.104. } h=\lambda(k+3 / 4) /(n-1), \text { where } k=0,1,2, \ldots,\\ &\text { (b) } I_{\max } \approx 8 I_{0} \end{aligned}
Prev
Next