1. Announcements 11/21/11 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

2. Reading quiz Which of the following is NOT true of the 3D “wave vector”? a. a.Its magnitude is equal to 2  /. b. b.In a plane wave, it points in the same direction everywhere in space. c. c.In a spherical wave, it points in the same direction everywhere in space. d. d.It tells us which way the wave is going. e. e.In 1D it reduces to the wave number k.

3. Waves in 3-dimensions Plane waves a. a.polarization Wave vector a. a.direction of wave Spherical waves General Form Specific Example

4. Student-designed problem: Transverse Wave 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?

5. Lasers What makes a laser special? (answers from class) Some of my answers: a. a.Single wavelength b. b.Intense c. c.Collimated d. d.Coherence (spatial, temporal) Actual laser spectrum is over 100  narrower than the width of the red line Blackbody spectrum Laser spectrum

6. Lasers Principal components: 1. Gain medium 2. Laser pumping energy 3. High reflector 4. Output coupler 5. Laser beam Energy (light, electrical, etc.) AbsorptionEmission light Stimulated Emission Image & list from Wikipedia Energy (light)

7. More Wikipedia Green laser pointer 1. gain medium (Nd:YVO 4 crystal) 2. laser pumping energy (808 nm LED beam) 3. high reflector 4. output coupler 5. laser beam

8. More Wikipedia

9. Circular Polarization Pictures from Wikipedia Remember these pictures? Blue & green both represent electric fields. E x out of phase with E y.

10. Optical Retarders, aka “Wave plates” Quartz, SiO 2 : n o = 1.544, n e = 1.553 Calcite, CaCO 3 : n o = 1.658, n e = 1.486 Pictures from Wikipedia Calcite crystal: