Skip to Main Content

Introduction To Fourier Optics Goodman Solutions Work -

HathiTrust is a partnership of academic & research institutions, offering a collection of millions of titles digitized from libraries around the world.

Let’s address the elephant in the room. A Google search for the exact phrase “introduction to fourier optics goodman solutions work” yields a fragmented landscape:

Step 1 – Fresnel integral: ( U(x,y,z) = \frace^ikzi\lambda z e^i\frack2z(x^2+y^2) \iint t(\xi,\eta) e^i\frack2z(\xi^2+\eta^2) e^-i\frac2\pi\lambda z(x\xi+y\eta) d\xi d\eta )

Step 2 – Approximation for large z (Fraunhofer): The quadratic phase factor inside the integral ( e^i\frack2z(\xi^2+\eta^2) \approx 1 ) when ( z \gg \frack(a^2+b^2)2 ).

Step 3 – Separable integrals: ( U = \frace^ikzi\lambda z e^i\frack2z(x^2+y^2) \left[ \int_-a/2^a/2 e^-i2\pi x\xi/\lambda z d\xi \right] \left[ \int_-b/2^b/2 e^-i2\pi y\eta/\lambda z d\eta \right] )

Step 4 – Evaluate: Each integral yields ( a \cdot \textsinc(a x/\lambda z) ) and ( b \cdot \textsinc(b y/\lambda z) ).

Step 5 – Intensity: ( I(x,y,z) = \left( \fracab\lambda z \right)^2 \textsinc^2\left( \fraca x\lambda z \right) \textsinc^2\left( \fracb y\lambda z \right) )

Why this is good: It shows approximations, separability, and units. A novice learns when the Fresnel → Fraunhofer transition occurs.

Problem: Compute the diffracted intensity pattern from a rectangular slit. The Naive Approach: Square the sinc function. The Goodman Solution Approach:

Why this "works": Goodman forces you to keep the phase term. Most students forget the quadratic phase factor in the Fresnel kernel. The solution works because it keeps the phase until the intensity (absolute square) kills it in the far field.

Before discussing solutions work, one must understand the pedagogical hurdles the textbook presents.

Take the provided solution and re-derive it on a blank sheet without looking. If you cannot reproduce it, you haven’t learned it.