Announcements 3/19/12
Prayer

Office hours: next two weeks only 3-3:30 pm MWF

There are substantial typos in problem P10.2.
a. In the equation in part (c), the first two “phi”s
should be “theta”s.
b. In the sentence on the next page, it should say
“Describe how this wave behaves as a function of r
and theta”. (Also: you don’t have to give a detailed
description of how it varies with r and theta, just a
couple of general observations.)
Please make the changes right now in your books.

Daily Comic
In the Bleachers
Reading Quiz

 E (r )  k E (r )  0 is called the __________
equation:
a. Arago
b. Fraunhofer
c. Fresnel
d. Helmholtz
e. Kirchhoff
2
2
Reading Quiz

Huygen’s principle involves:
a. convolutions
b. paraxial light
c. ray methods
d. wavelets
Reading Quiz

Babinet’s principle relies on:
a. calculus of variations
b. linear superposition
c. scalar approximation
d. small angle approximation
Helmholtz equation

vector vs. scalar
Goal: Huygens’ Principle
“Fresnel’s diffraction formula”
ikR
e
E ( x, y, z ) ~  E ( x, y, 0)
da
R
aperture
2
2
2


R  (x  x )  ( y  y )  z
R
r
r
Deriving “Fresnel Approximation” formula
The Four Complicated Integral Formulas

“The Fresnel approximation”

(10.13)

“Fresnel’s diffraction formula”

“The Fresnel-Kirchhoff diffraction formula”

“The Fraunhofer approximation” (next time!)

HW problem P10.6, due Tues 3/27/12
x=0, y=0
Fresnel approx., with
cylindrical symmetry
Fraunhofer approx.,
with cylindrical symm.
“Fresnel-Kirchoff”, but really
just original Fresnel’s
diffraction formula
Babinet’s Principle