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Diffraction of Light

Problem 5.104

A plane light wave with wavelength λ\lambda and intensity I0I_{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.P . In the middle of the aperture there is a round recess equal to half the Fresnel zone. What must the depth hh of that recess be for the intensity of light at the point PP 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}
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