Download lecture 36 - waves in 3 dimensions, optical devices

Announcements 11/21/11
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Prayer
Exam 3 review session today, 5-6 pm, room C258
Lab 10 due tomorrow
Exam 3 starts Monday after break, goes through
Saturday
Final exam: in Testing Center, M-Th week of finals
Frank &
Ernest
Reading quiz
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Which of the following is NOT true of the 3D
“wave vector”?
a. Its magnitude is equal to 2p/l.
b. In a plane wave, it points in the same
direction everywhere in space.
c. In a spherical wave, it points in the same
direction everywhere in space.
d. It tells us which way the wave is going.
e. In 1D it reduces to the wave number k.
Waves in 3-dimensions
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Plane waves
a. polarization
Wave vector
a. direction of wave
General Form
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E  E0pˆ cos k x x  k y y  k z z  t
Specific Example
E  E0
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Spherical waves
1
 xˆ + yˆ  cos  kz  t 
2
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Student-designed problem: Transverse Wave
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What direction do you want the wave to be
traveling in?
What direction do you want the wave to be
oscillating in?
What wavelength do you want the wave to have?
What do you want the wave’s amplitude to be?
What frequency (or velocity) do you want the wave
to have?
What do you want the overall phase of the wave to
be?
Lasers
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What makes a laser
special? (answers from
class)
Actual laser spectrum
is over 100 narrower
than the width of the
red line
Laser spectrum
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Some of my answers:
a. Single wavelength
b. Intense
c. Collimated
d. Coherence (spatial,
temporal)
Blackbody spectrum
Image & list from Wikipedia
Lasers
Stimulated
Emission Emission
Absorption
Energy
(light)
(light,
electrical,
etc.)
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Principal components:
1.
2.
3.
4.
5.
Gain medium
Laser pumping energy
High reflector
Output coupler
Laser beam
light
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Green laser pointer
More Wikipedia
5. laser beam
3. high
reflector
1. gain medium
(Nd:YVO4 crystal)
2. laser pumping energy
(808 nm LED beam)
4. output
coupler
More Wikipedia
Circular Polarization
Remember these pictures?
Blue & green both represent
electric fields.
Ex out of phase with Ey.
Pictures from Wikipedia
Optical Retarders, aka “Wave plates”
Calcite crystal:
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Quartz, SiO2: no = 1.544, ne = 1.553
Calcite, CaCO3: no = 1.658, ne = 1.486
Pictures from Wikipedia