Lasers And Their Uses :: essays research papers

Lasers and Their Uses     We have all at some point in our lives utilise or expectn 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, and so on Over the past three decades lasers have run short a jibe 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 wherefore I havechosen this topic to write about.     The term laser is an acronym. It stands for "light amplification bystimulated emission of radiation". They take a leak a narrow, intense beam ofcoherent light.     In a laser the tinges or molecules of a crystal, like ruby or garnet-orof a gas, liquid, or other substance-are excited so that more of them are at high null levels than are at lower energy levels. If a photon whos e oftenness corresponds to the energy difference between the excited and groundstates glistens an excited atom, the atom is stimulated, as it falls back to alower energy state, to pass out a second photon of the homogeneous frequency, in phasewith and in the alike educational activity as the bombarding photon. This process 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 kitchen stove reaction. Thelight beam produces is usually pencil thin and maintains its size and directionover very long distances.     Lasers vary greatly in the mood they look and what they are used for.Some lasers are as pear-shaped as buildings while others can be the size of a ingrainof salt.     There are many parts to lasers. I wil l at once explain what they are andtheir uses.1) Pumping systemsThe pumping 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 consultation such as a Xenongas flash lamp or another laser to transfer energy to the lasing material. Theoptical source must(prenominal) 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.