Beginning of Essay
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 th ....

Middle of Essay
.... 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 process is called stimulated emission. The bombarding photon of the emitted photon may then strike other excited atoms, stimulating further emission of photons, all of the same frequency and phase. This process produces a sudden burst of coherent radiation as all the atoms discharge in a rapid chain reaction. The light beam produces is usually pencil thin and maintains its size and direction over very long distances. Lasers vary greatly in the way they look and what they are used for. Some lasers are as large ....