Ruby Lasers
A ruby laser consists of a flash tube (like you would have on a camera), a ruby rod and two mirrors (one half-silvered). The ruby rod is the lasing medium and the flash tube pumps it.
1. The laser in its non-lasing state |
2. The flash tube fires and injects light into the ruby rod. The light excites atoms in the ruby. |
3. Some of these atoms emit photons. |
4. Some of these photons run in a direction parallel to the ruby's axis, so they bounce back and forth off the mirrors. As they pass through the crystal, they stimulate emission in other atoms. |
 5. Monochromatic, single-phase, columnated light leaves the ruby through the half-silvered mirror -- laser light! |
