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“Laser” stands for light amplification by the stimulated emission of radiation. It is one of the most productive inventions of the twentieth century. Several kinds exist today, many of which are based on the idea of atomic quantum structure.
Basically, lasers work on the idea of photon absorption and emission. This happens through the excitement of electrons, in which the electrons shift from a low energy state to a high-energy state. Two types of emissions exist, spontaneous and stimulated. Lasers most often used stimulated energy. In stimulated emission, oncoming photons excite the electrons to change energy level. However to produce the emission, the oncoming photon’s energy must equal that of difference between the two energy levels. It’s given by the formula,
Three important features exist in stimulated emission. First, one photon exits, and two enter. Second, all photons travel in the same direction. Third, all the photons represent an electromagnetic wave, which have the same frequency going in or going out.
Holography is a process for creating 3-d images. A hologram is a photographic film that stores information of the holographic image. Laser light hits a half-silvered mirror, which transmits and reflects some of the light. The reflected light is known as object beam and the transmitted light as reference beam. The objective beam strikes the object at two points on the focused object. Both beams hit the hologram, producing the image. As mentioned before, laser has the same frequency at any point, which will create a stable phase relationship on the hologram. With this stable phase relationship and both beams traveling at different distances, the image can be distorted, a trademark of holography photos. Holography is used in credit cards for identification purposes. Other uses include high point displays for the dashboard in powerful fighter planes, computerized information storage and retrieval systems, and highly accurate biomedical measurement.
What are some lasers today called?
A few examples of lasers include the helium/neon, ruby, argon-ion, the carbon-dioxide, gallium arsenide solid-state, and chemical dye laser.
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