Lasers+(KC+and+Taylor)

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=What is Quantum Mechanics? =

Quantum Mechanics is a mathematical theory predicting the behaviors of microscopic particles and descriptions of atoms. (The word quantum actually means a small, definite amount.) Physists understand the concepts of this theory, the parts put together, and how it is performed. However, there is a disagreements between phsysists about what kind of world this theory illustrates and what our world is like. This is because the interpretation of the calculations from the theories defy everything that humans have ever known. The question that causes the controversy is what microscopic world affects us and how. This theory is interpreted in its capacity as a mathematical machine and the effect that the microscopic world has on the macroscopic world. The main purpose of quantum mechanics is to understand how atoms work because they are so useful to the world today, such as affected our machines, instruments, and other materials.

=The History of Lasers = The laser (__L__ight __A__mplification by __S__timulated __E__mission of __R__adiation) was first operated on May 16th, 1960 in the Hughes Research Laboratory, created by a man named Theodore Maiman. A high power flash lamp was shone onto a ruby rod with silver coated surfaces. The laser was only a short flash, just enough to excited the ruby rod, but it did provide a lot of power. The predecessor of the laser, the maser (__M__icrowave __A__mplification by __S__timulated __E__mission of __R__adiation), were only used for infrared light, visible light, and microwave frequencies. The maser was constructed by Townes, Basov, and Prokhorov in the 1950s. The newly invented laser could empty the ground state of the ruby rod so that stimulated emission could happen from an excited to a ground state. Maiman published an article about his laser in __Nature__. Some scientists were skeptical about this laser because there weren't the expected bright beams. Maiman used this laser only to analyze the spectrum of the light emitted from it. However, there were soon more experiments with lasers so that bright red beams could be seen from the Hughes  Research  Laboratory, and from Schawlows in New Jersey.  <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">A lso in 1960, a neon-helium laser was made by Ali Javan, William Bennett, <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">and Donald Herriott, that had the narrowest beam with pure frequency. In 1969, a ruby laser sent a beam to the moon and was reflected back. This helped scientists and physists measure the distance to the moon from the round trip time of the laser. <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">In 1971, the idea of a holographic method, which was the first use of laser technology, was introduced by Gabor. Holograms were responsible for creating 3-D pictures, and also provided information on musical tones for instruments. In 2000, Alferov and Kroemer were rewarded for creating miniature lasers with cheap, small light. There are now used all over the world in appliances.

=<span style="font-family: Georgia,serif; font-size: 120%;">Uses =

<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Lasers are now used for things such as supermarket bar code readers and laser pointers. The modern laser produces much higher power than previous ones. Since they have more precise measurement than previously, they're gentler, and they have a lower temperature. Carpenters use laser instead of spint levels to ensure the materials they are working with are situated properly.Hunters also use a laser instead of ordinary telescopes to get a direct hit on the animals they are after. Even when you are watching a DVD- a laser is being used. This cannot be done with any other light source other than a laser because the beam of light has to be focused on as small of an area as possible to "read" all of the stored information. Laser pointers are another use of a laser are used in classrooms and other learning and teaching environments. Lasers are also be used by cops within their speed guns. The beam is sent towards a reflecting piece of the car and bounces back while being mixed with the light that has not yet hit the car resulting in oscillation, the higher the frequency the faster the car is moving. Another main use for laser is to cut precise patterns in glass, metal, and wood. Lasers can be found within many industries to cut and weld metal- or even to cut through hundreds of layers of fabric at once. Lasers can even be found in space! Lasers are commonly used in a spectrometer. A spectrometer uses light to identify the chemical composition of matter. A spectrometer can be sent to Mars to help discover if there is life on the planet. In fact NASA launched a special laser spectrometer called the //Tunable Laser Spectrometer// this past year. [|**Laser Cutter**] It also reshape the corneas in peoples' eyes to help restore vision. Another surgery done by lasers is brain surgery. Lasers are now being used to perform other surgeries on various parts of muscles and tissues within the body. The laser is much more precise than any surgeon could be, and therefore is used. Also, the heat from the lasers cause the tissue around the cut to heal, and lessen the amount of bleeding. Not only this- but the use of lasers is also less painful to the patient. Lasers can also be used to provide heat and trasmit telephone signals. Lasers are also being experimented with to spark miniature suns to provide a cleaner, healthier energy through fusion. media type="youtube" key="dU6jJHFxNbI" height="344" width="425"

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=<span style="font-family: Georgia,serif; font-size: 110%;"> = =<span style="font-family: Georgia,serif; font-size: 120%;">How Lasers Work = <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">A typical laser has three main parts, the active medium, an energy source, and an optical cavity. The active medium is an electrically charged gas-like substance that can be made to create laser light. The energy source is a device that supplies the active medium with energy through a process known as pumping. Some energy pumps include another laser or a flash lamp. The optical cavity is what encloses the active medium. Normally it has a mirror at each end. Most often, one mirror has a fully reflecting sirface and the other has a partly reflecting surface. The laser beam exits the laser through the mirror with the partly reflecting surface. Laser light is the result of stored enery in the active medium. The atoms normally exist in the ground state, the state of lowest energy. However, atoms can exist in higher energy states called excited states.The excited atom can only hold the extra energy for only a portion of second before the atom releases the enrgy in the state of a photon, and returns to the ground state. This process is known as spontaneous emission. When the laser is turned on, the energy source fives off photons. Atoms absorb the photons and reach their excited state. The excited then realease the photons displaying light. Some of the light reflects off the mirrors and some remains in the cavity. The stimulated emission increases rapidly and the light reaches the point where it is so strong that a small amount of it exits through the partly reflcting mirror as a beam.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Lasers are known as "quantum light." Laser light, unlike sunlight or any other type of light, is orderly. Lasers provide light by utilizing the forces of the light and directing them in a certain direction. The amplification that is involved with lasers is done by magnifying the light, which helps intensify or de-intensify the laser. The light in the laser comes from stimulation. <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">The release of these photons in the electrons in called emission, and the entire situation stimulation and emission is also known as radiation. When these processes are controlled and mirrors are set up to reflect the light back and forth, a laser is thus created.

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=<span style="font-family: Georgia,serif; font-size: 120%;">Laser Properties = <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Lasers have unique properties about them. One of these properties, coherence, arises from stimulated emission to provide amplification. Oridinary light is not coherent like lasers because it comes from independent atoms that emit at 10x-8 seconds.Laser light is also highly collimated. This means that the beam that comes from the laser is very thin and doesn't have a lot of divergence. This amount of collimation is because the cavity of the laser has almost parallel front and back mirrors that constrict the beam to a perpendicular path. The beam that is passed back and forth between mirrors gains intensity for the stimulated emission. A high collimision can be very dangerous to a human being. Humans are taught not to look directly into a laser because they can cause immediate damage to one's retina. However, lasers also help humans a lot because this high collimision contributes to medical and industrial applications of a laser. Lasers help medicine by being used as a sharp scalpel; they help industries by being fast, powerful, and controlling.The other property is that lasers are monochromatic. Lasers have a single spectral color and it is of the purest light. Lasers are not totally monochromatic, because the spectral emission does not have finite width. The emission lines have many resonant modes of the laser cavity.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 180%;"> =<span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">How Lasers Relate to Quantum Mechanics = <span style="font-family: 'Times New Roman',Times,serif; font-size: 90%;"> <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Lasers and quantum mechanics are related.​ The Aufbau Principle is a mutual concept with lasers and quantum mechanics. The Aufbau Principle determined that electrons in atoms are always going to jump to lower energy levels. Earlier, it was discussed that for lasers to work, they have to jump between an excited and ground state. This follows Aufbau's rule because the excited electrons always want to jump back to their normal state, and sometimes will want to jump to its excited state as well. This is one of the quantum concepts of a laser.

<span style="font-family: 'Times New Roman',Times,serif; font-size: 130%;"> =<span style="font-family: 'Times New Roman',Times,serif; font-size: 130%;">Laser Shows = <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;"> Lasers can be used for entertainment, such as with laser shows. Laser shows are extremely high-tech, fragile, and exciting to watch. There are two types of effects with lasers: beam effects and screen effects. Beam effects happen when the laser beam is travelling through the air. Beam effects have different types of beams, including static and dynamic (scanned) beams. Static beams are originated from a beam table and are switched on and off. They can be extremely dangerous, so as a precaution, these beams must be separated from audience contact. Dynamic, or scanned, beams move. These beams originate from fans, sequences, sheets of light, cones, or tunnels of beams. They are shone through moving difraction grating effects. Screen effects require a screen or surface for them to be visible. Some other surfaces these beams are shone on are domes, walls, billboards, or buildings. Animation and graphics are types of screen effects, as well as cycloids, abstracts, and lumia. media type="youtube" key="gBwS-IyVWwI" height="344" width="425"



<span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">There are 6 subsystems that are required for a laser show to work: Laser and exciter, laser projector, scanners, control console, laser graphics system, and outboard equipment. <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">Three types of lasers are usually used in laser shows: Ion lasers that use Argon and Kyrpton, Diode Pumped Solid State Lasers, or Diode Lasers. The most commonly used one is the Argon laser. This laser gives off a blueish hue and can be split into blue and green by using a yellow dichro or prism. A Krypton laser can be produced into red light or many different colored light. Together, Argon and Kyrpton lasers make a white beam. Solid State lasers pump series of crystals instead of gas. These produce light by spontaneous emission and they excite atoms in a crystal rather than gas. These lasers are smaller, lighter, much more reliable, and use less electrical energy. Diode lasers are usually used in a low-power laser show. They cannot be accessed with high power outputs. These lasers are similar to an LED because they emit light when power is applied. The most common use of these type or lasers is a laser pointer.

= <span style="font-family: 'Times New Roman',Times,serif; font-size: 120%;">Fun with Lasers =

[|Adjust the prisms to direct the laser beam to hit their mark!]

[|Watch how precise the beam of the laser is to light the small heads of matches!]