Summary
- Optical activity
- Dichroism
- Birefringence
- Wave plates
- The two-level atom
- absorption B12
- spontaneous emission A21
- stimulated emission B21
- steady-state population ratio
- thermodynamic equilibrium
- in-class 13.17, 13.18
- Lasers and interactive applet
- population inversion
- resonant cavity
- nonthermal excitation
- types of lasers
- He-Ne: cheap, bright
- Ar+: many λ, good power
- CO: IR high power industrial
- Nd:YAG: high power pulsed
- Ti:Sapphire: tunable in IR
- liquid dye: tunable IR to UV, needs pump laser
- diode: solid state, tunable, cheap
Light
Amplification by
Stimulated
Emission of
Radiation