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Published byErlin Atmadja Modified over 6 years ago
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Announcements 2/17/12 Reading assignment for Tuesday
Prayer Monday is holiday Tues is virtual Monday—we have class! Reading assignment for Tuesday Remove section 7.1 (we’re covering it today) Keep section 7.2 Add Colton Fourier series/transforms handout (I will hand it out now)
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Reading Quiz The technique of finding the complex index of refraction, n and k, from polarization changes in reflectance is called: circularometry ellipsometry hyperbolometry linearometry parabolometry
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linear polarizer, angle q
Ellipsometry 3 starts linear, angle a linear polarizer, angle q 1 2 does something Wikipedia
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Ellipsometry, cont. Two measurements, two unknowns deduce rs and rp
deduce n and k if multilayers: lots of measurements!
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On to Chapter 7!
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Poynting vector review
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Poynting vector for a sum of plane waves
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Two Different Velocities
What happens if a wave pulse is sent through a dispersive medium? Nondispersive? Dispersive wave example: f(x,t) = cos(x-4t) + cos(2 (x-5t)) What is “v”? What is v for w=4? What is v for w=10? What does that wave look like as time progresses? (next slide)
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Mathematica What if the two velocities had been the same? 0.1 seconds
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Time Evolution of Dispersive Pulse
Credit: Dr. Durfee Note: frequencies are infinitely close together Peak moves at about 13 m/s (on my office computer) |Amplitude|2 for each frequency component Wave moving in time
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Phase and Group Velocity
Credit: Dr. Durfee Window is moving along with the peak of the pulse 12.5 m/s (peak) 13 m/s
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From Wikipedia http://en.wikipedia.org/wiki/Group_velocity
Example where vphase > vgroup
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One of my contributions to Wikipedia
Example where vphase is negative!
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More movies
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Start on Fourier handout, if time
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