(Solved): Poisson Spot. Consider a plane wave with wavelength 500nm incident on an opaque circular spot of ...

Poisson Spot. Consider a plane wave with wavelength $500\mathrm{nm}$ incident on an opaque circular spot of radius $1\mathrm{mm}$. This wave then propagates a distance $d$ and is imaged. (a) Draw the two rays that diffract from the top and bottom of the spot, respectively, to reach the center point of the shadow region. Write an expression for the phase difference between the light from each of these two 'rays'.