Laser Technology Essays - Optics, Laser Science, Physics, Light

Laser Technology Laser Technology The laser is a device that a beam of light that is both scientifically and practically of great use because it is coherent light. The beam is produced by a process known as stimulated emission, and the word "laser" is an acronym for the phrase "light amplification by stimulated emission of radiation." Light is just like radio waves in the way that it can also carry information. The information is encoded in the beam as variations in the frequency or shape of the light wave. The good part is that since light waves have much higher frequencies they can also hold much more information. Not only is the particle the smallest light unit but it is a particle as well as a wave. In beams of light whether they are ordinary natural or artificial the photon waves will not be traveling together because they are not being emitted at exactly the same moment but instead at random short bursts. Even if the light is of a single frequency that statement would also be true. A laser is useful because it produces light that is not only of essentially a single frequency but also coherent, with the light waves all moving along in unison. Lasers consist of several components. A few of the many things that the so-called active medium might consist of are, atoms of a gas, molecules in a liquid, and ions in a crystal. Another component consists of some method of introducing energy into the active medium, such as a flash lamp for example. Another component is the pair of mirrors on either side of the active medium which consists of one that transmits some of the radiation that hits it. If the active component in the laser is a gas laser than each atom is characterized by a set of energy states, or energy levels, of which it may consist. An example of the energy states could be pictured as a unevenly spaced ladder which the higher rungs mean higher states of energy and the lower rungs mean lower states of energy. If left disturbed for a long time the atom will reach its ground state or lowest state of energy. According to quantum mechanics there is only one light frequency that the atom will work with. There are three ways that the atom can deal with the presence of light either it can absorb the light, or spontaneous emission occurs, or stimulated emission occurs. This means that if the atom is at its lowest state that it may absorb the light and jump to its high state and emit extra light while doing so. The second thing it may do is if it is at its highest state it can fall spontaneously to its lower state thus emitting light. The third way is that the atom will jump from its upper state to its lower state thus emitting extra light. Spontaneous emission is not effected by light yet it is rather on a time scale characteristic of the states involved. That is called the spontaneous lifetime. In stimulated emission the frequency of the light is the same as the frequency of the light that stimulated it. Carbon-monoxide, color center, excimer, free-electron, gas-dynamic, helium-cadmium, hydrogen-fluoride, deuterium-fluoride, iodine, Raman spin-flip, and rare-gas halide lasers are just a few of the many types of lasers there are out there in the world. The helium-neon laser is the most common and by far the cheapest costing about $170. The diode laser is the smallest being packed in a transistor like package. The dye laser are very good for their broad, continuously variable wavelength capabilities. The theory of stimulated emission was first proved by Albert Einstein in 1916, then population inverse was discussed by V. A. Fabrikant in 1940. This led to the building of the first ammonia maser in 1954 by J. P. Gordon, H. J. Zeiger, and Charles H. Townes. In July of 1960 Theodore H. Maiman announced the generation of a pulse of coherent red light by means of a red crystal- the first laser. In 1987 Gordon Gould won a patent he had been trying to get for three years to build the first gas-discharged laser which he had conceived in 1957. In that same patent the helium-neon was included. Bibliography: Bertolotti, M., Masers and lasers: An Historical Approach (1983); Kasuya, T., and Tsukakoshi, M., Handbook of Laser Science and Technology (1988); Meyers,Robert, ed., Encyclopedia of Lasers, 3d ed. (1989); Steen, W. M., ed., Lasers in Manufacturing (1989); Whimmery, J. R., ed., Lasers: Invention to Application (1987); Young, M., Optics and Lasers, 3d rev. ed.

Arab Resentment for the US essays

Arab Resentment for the US essays On September 11, 2001, a horrific terrorist attack was waged against the United States. Thousands of working men and women were killed in the attacks, leaving the country grieving and angry. On that day, I asked myself, What could make those people hate America so much that they would do such a terrible thing? Since that day, finding the answer to that question has been a priority of mine. I have concluded that the varying interpretations of Islamic values, Americas indulgent culture, and United States foreign policy are all sources of resentment for America in the Middle East. During this time of terrorism, many Americans have been looking for a religious reasoning to account for the resentment for the United States among many Middle Eastern peoples. In contrast to the Middle East, American culture tends to be ostentatious and thrives on indulgence. It has been assumed that the people of the Middle East, being predominantly Muslim, fear the corruption of their culture by the omnipresent American culture. Many speculators have looked to the Koran for explanations. However, the Koran can be translated in many ways, making it difficult for non-Arabic speaking people to interpret its meaning. Despite this difficulty, in the recent months since the attacks, many Americans have been interpreting passages of the Koran to be promoting the killing of non-believers as well as violent actions against suppressors of Islam. In an article from the New York Times titled This Is a Religious War, the author interprets a passage of the Koran as saying: Believers! Wage war against such of the infidels as are your neighbors, and let them find you rigorous. The instruction to wage war in this passage might be interpreted figuratively by some, but considering the recent events, it seems as though the members of Al Qaeda took this instruction literally. On the other hand, the Koran is ren...