announcements 3/28/12
DESCRIPTION
Announcements 3/28/12. Prayer Exam review problems for sign-up. Calvin & Hobbes. Reading Quiz. A lens placed after a diffraction aperture causes the Fraunhofer pattern to be produced: before the focal length at the focal length after the focal length (but at a finite distance) at infinity. - PowerPoint PPT PresentationTRANSCRIPT
Announcements 3/28/12 Prayer Exam review problems for sign-up
Calvin & Hobbes
Reading Quiz A lens placed after a diffraction aperture
causes the Fraunhofer pattern to be produced:
a. before the focal lengthb. at the focal lengthc. after the focal length (but at a finite
distance)d. at infinity
Lenses
Lenses What it object is not at infinity?
a. What appears at q?b. What appears at f?
“Fourier transform plane”
f f f f
Object at f:
Lens Fourier Transforms
From Hecht
at focus of lens
“Fourier Transform smoothing”
From Hecht
Before After
Reading Quiz
What does the “Rayleigh criterion” tell us?a. The angle at which both light
polarizations have equal reflection coefficients
b. The angle at which p-polarized light has minimum reflection
c. The angular separation resolvable by an imaging system
d. The number of orders produced by a diffraction grating
Reading Quiz The Rayleigh criterion for resolving two
point light sources comes from:a. Fourier transforms of delta functions.b. Jinc functions’ maxima and minima. c. Lagrange multipliers.d. Parallax of stars.
Simple Telescope
Circular Aperture, again
What do you get in this situation?
What if there’s a lens in the hole?
What if there isn’t a board?
What if you have two light sources?
patt
ern
at in
finity
patt
ern
at f
ocus
supe
rimpo
sed
patt
erns
at
focu
s
f
board with hole
Rayleigh: 2nd peak at position of first minimum
Rayleigh Criterion
plotted vs (krb/f), = D/
Mathematica “FindRoot” command: / = 1.21967…
min.resolve 1.22D
(using sin )
Curve is (J1(x)/x)2
Rayleigh Criterion
(= first zero of J1(x))