Questions on Laser Components

1. What are the three primary components of a laser?
2. What different types of laser medium are used?
3. What is a pump?  Describe the different types of pumps.
4. What is a resonant cavity?
5. Describe how the resonant cavity produces a collimated laser beam.
6. What is the beam divergence of a laser caused by?  What is a typical value for it?
7. What does the term gain mean?  Is it related to pain?
8. Describe why a typical laser has only a few modes, while the resonant cavity produces a huge number of them.