Lasers And Their Uses :: essays research papers

Lasers and Their Uses     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-codescanners, etc. Over the away three decades lasers have become a tool useddaily by many people and they have become very useful in scientific research.As you can see lasers are a very useful and important tool which is why I havechosen this content to write about.     The term laser is an acronym. It stands for "light amplification bystimulated emission of radiation". They produce a narrow, intense beam ofcoherent light.     In a laser the fragments or molecules of a crystal, like ruby or garnet-orof a gas, liquid, or other substance-are excited so that more of them are athigher energy levels than are at lower energy levels. If a photon whosefrequency corresponds to the energy difference between the excited and groundstates strikes an excited atom, the atom is stimulated, as it falls back to alower energy state, to emit a second photon of the same frequency, in phasewith and in the same watchfulness as the bombarding photon. This butt iscalled stimulated emission. The bombarding photon of the emitted photon maythen strike other excited atoms, stimulating further emission of photons, allof the same frequency and phase. This process produces a sudden burst ofcoherent radiation as all the atoms discharge in a rapid chain reaction. Thelight beam produces is commonly pencil thin and maintains its size and directionover very long distances.     Lasers vary greatly in the way they look and what they are used for. close to lasers are as large as buildings while others can be the size of a grainof salt.     There are many parts to lasers. I will now explain what they are andtheir uses.1) Pumping systemsThe p umping system is used to transmit energy to the atoms or moleculesof the medium used in the laser.a. optical pumping systems uses photons provided by a source such as a Xenongas flash lamp or another laser to transfer energy to the lasing material. Theoptical source must provide photons which correspond to the allowed transitionlevels of the lasing material.b. collision pumping relies on the transfer of energy to the lasing material bycollision with the atoms or molecules of the lasing material. Again, energieswhich correspond to the allowed transition must be provided. Thisoften done by electrical discharge in a pure gas - or gas mixture - in a tube.