Part one of term paper
We have all at some point in our lives used or seen someone use a laser. They are used in compact disc players for stereos or computers, laser surgery, laser printers, holography, cutting and borring metals, communication, bar-code scanners, etc. Over the past three decades' lasers have become a tool used daily by many people and they have b ...

Part two of term paper
... atoms or molecules of a crystal, like ruby or garnet-or of a gas, liquid, or other substance-are excited so that more of them are at higher energy levels than are at lower energy levels. If a photon whose frequency corresponds to the energy difference between the excited and ground states strikes an excited atom, the atom is stimulated, as it falls back to a lower energy state, to emit a second photon of the same frequency, in phase with and in the same direction as the bombarding photon. This p ...