Announcements 2/21/12 Prayer Exam results: curved 4 pts, see a. a.If you had Testing Center calculator issues that you feel affected your grade, please talk to me ASAP. b. b.If you did poorly and are concerned about your overall class grade, you can make an appointment to talk to me. Send me an . c. c.Students did the worst on the TIR problem (that we did in the in-class review!), probably due to complex Fresnel coefficients. There is a very high chance that complex Fresnel coefficients will show up again in some form on Exam 2. I’ll be out of town next week, Mon – Thurs. a. a.Dr. Peatross will substitute in lecture b. b.No office hours from me, obviously c. c.TAs will have their usual office hours

About the Fabry-Perot problem…

Reading Quiz These two graphs were given in the handout, plotted as a function of . Which applies to which section of the handout? a. a.Left = Fourier series, Right = Fourier transform b. b.Left = Fourier transform, Right = Fourier series c. c.Both = Fourier series d. d.Both = Fourier transform

Colton’s Fourier Series Summary with exponentials:

Fourier Series Example f(t) c n or c(  ) Why did I list the positive exponents first?

Colton’s Fourier Transform Summary Fourier Series Fourier Transforms with c n  c(  ) and n  0   A word about units: suppose f(t) is electric field. What are units of c(  )?

Fourier Transform Example f(t) c n or c(  ) Remember this?

Reading Quiz “Group velocity” is given by: a. a. c. b. b. d.

Reading Quiz Group velocity tracks the speed of the “ripples” resulting from the superposition of multiple waves a. a.true b. b.false

Two interfering plane waves