announcements 4/6/12 prayer exam 3 ends tomorrow i’ll be on the radio 5 pm tomorrow with the utah...

Announcements 4/6/12 Prayer Exam 3 ends tomorrow I’ll be on the radio 5 pm

tomorrow with the Utah Baroque Ensemble: 89.1 FM or Sirius XM 143 (BYU radio). An hour of classical-style choral music, pieces dating from ~1600 to ~2000.

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Reading Quiz Who developed the “A and B”

coefficients?a. Avogadro and Boltzmannb. Bohrc. Einsteind. Fermi e. Plank

Reading Quiz Which of these processes is not one

considered in Einstein’s A & B coefficient analysis?

a. spontaneous absorptionb. stimulated absorptionc. spontaneous emissiond. stimulated emission

Two Level System: Three Processes

Energy (light, electrical, etc.)

AbsorptionEmission

light

Stimulated Emission

Energy (light)

light: incident + more

A & B for a Two Level System and application to lasers

Lasers

Principal components:1. Gain medium2. Laser pumping energy3. High reflector4. Output coupler5. Laser beam

Image & list from Wikipedia

From Saleh & Teich,

Fundamentals of Photonics

(2007)

From Wikipedia

Lasers!!

From Saleh & Teich, Fundamentals of Photonics (2007)

Semiconductor Alloys

From http://www.tf.uni-kiel.de/matwis/amat/semi_en/kap_5/backbone/r5_1_4.html

Bandgap Engineering

Quotes from web page author