Lasers:
Light Amplification by the Stimulate Emission of Radiation, in short LASER, was first introduced by Max Plan in 1900. He proposed the idea that light is made up of energy packets so it can form electromagnetic radiation. This was the core idea behind the invention of Lasers. In 1917, German physicist Albert Einstein explained that light can be quantized into stimulated glitter. Until 1940s, physicist and engineers were not able to use this principle of quantization of light. However in 1950s, engineers worked together to use energy as the prime resource for stimulated glitter.
Charles Townes at the Columbia’s University, Joseph Weber at the Maryland’s University and Alexander Prokhorov and Nikolai G Basov at the Lebedev Laboratories in Moscow worked on this case study presented by Einstein. At that time these engineers attempt to achieve a breakthrough invention that was later names as Microwave Amplification by the Stimulated Emission of Radiation, called MASER. Maser was a system that was operating on the principle that it was combining strong microwave radiations and converts them into contrast of light. This led to the study of microwave communications. Townes and his fellow engineers thought that it was possible to engineer a device that produces powerful beams of light of higher frequency and shorter wavelengths to create what is called lasing medium. These engineers’ work was left to Theodore Maiman in 1960 when first laser was created with a lasing medium of ruby. It promoted high-energy flashes of intense light. Prokhorov and Townes were awarded as Nobel Prize of Science in 1964 based on their research and contribution towards this new technology of Laser.
Laser was a breakthrough technological idea but in initial years it was not planned and managed well enough that many sectors can be beneficial from this technology. It wasn’t used in military service of beam weapons in initial years but its main beneficial sector was information and transmission through the atmosphere. Later this technology was improved by Maiman and other engineers. This new upgraded technology of laser helped other sectors to be beneficial from this technology, for example, engineers improved laser weapons and lasers were started to be used in medical treatments as well as these laser has become known as a powerful and tiny resource of heat and energy. Even in current era, we used lasers in corrective eye surgery, supplying and exact source of light and heat energy for slicing and burning tissues in medical surgeries.
The laser is an abbreviation word for light amplification by stimulated emission of radiation, while people used LASER as a noun.
In everyday life, we can see atoms emitting energies, in form of light, heat or power. A laser is a device that focuses the intense beam of light and increases the frequency, in order to be used in industrial or medicine areas of work. Atom of radiating elements radiates their light in unplanned scattered point at accidental times.
The phenomenon is about production of coherent light frequency from a single accurate resource.
Exciting atoms or molecules
In laser system, the atoms increase their kinetic energies this falling in the state of excitation. Atoms and molecules of crystal, garnet, radium, ruby and other gases and materials are excited in laser cavity, so most due to this process the electrons fall into higher energy orbits. Reflective surfaces at both ends of cavity enable energy to reflect on both sides, as shown in figure below.
In above shape, the flash lamp light excites the molecules in the ruby rod, that it’s called “optical pumping”, and they pick up back and forth in the middle of two mirrors till coherent light flees from the cavity.
If a photon whose frequency match to the power variety among the excited and ground states hits an excited atom, the atom is motivated as it falls back to a lower energy state to give off a second photon of the same. Frequency, phase and with the same point as the photon bombarded.
This process is called as stimulated emission. These excited atoms and molecules may strike by emission of photons of the same frequency, same phase angle and same amplitude. This stimulating process of emission of photon produces coherent radiations. As well as the atoms are discharged in this process in a quick chain reaction.
Varieties of sizes and uses
Size of Laser varies according to their usage and source element. Semiconductor lasers can be as tiny as grain of salt and solid state and gas lasers can be as big as the size of warehouse. Most of the lasers produce a thin beam of light as small as pencil lead.
Lasers are widely used in industries for cutting purposes and drilling through metals and other substances. In medical areas lasers are used in surgery of sensitive areas. Lasers are also widely used in communications, scientific studies and 3d laser engraving. Lasers are also used as integral parts in devices like, bar code scanners, scanners, laser printers and optical device or CD players.
Lasers Importance in world today
The knowledge about laser is proved very helpful scientific tool in general applied form. It was published by author L. Schawlow and Charles H. Town in 1958 and practically it has been made for different usage. Their experiences lead to many researches by scientists at Bell Labs, many universities and technical laboratories around the world.
The laser was formed by engineers to change electrical transmittal over copper cable especially in communication. In 1960, pulses of light transmitted by Schawlow, D.F. Nelson, R.J. Collins and others between Bell Labs convenience in Murray Hill, N.J., and Crawford Hill, N.J., 25 miles far away to find how to send the pulses presented huge problems. Then it called an optical maser, Townes’ preferred name for the device generates an intense and very tight laser beam that is very brighter more than million times than the sun.
Lasers are comprehensive today
Lasers are used in some broader fields of request such as medicine, industry, civil engineering, army systems, surveying, scientific instrumentation and consumer electronics. Actually billions of lasers are using nowadays and they used in different size from a tiny semiconductor systems to large size as a fair average.
Introduce the leaderships of laser
There are so many scientists who worked on laser from 1900 till now such as Max Plank1900, Albert Einstein1916, Rudolph W Landenburg1928, Valentin A Fabrikant 1940, Willis E Lamb RC Rutherford 1947, Charles H Townes 1951, Charles H Townes Joseph Weber James P. Gordan 1951, Robert H Dicke 1954, Nicolas Bloembergan 1956, Charles H Townes Sketches & Gordon Gould 1957, Arthur L Schawlow Charles H Townes1958, John D. Myers1959, Arthur L Schawlow & Charles H Townes, Theodore Maiman, Hughes, Peter P Sorokin & Mirek Stevenson, Ali Javan1960 and ….., Wolfgang Keterle1996, Wolfgang Ketterle1997, Ozdal Boyraz & Bahrom Jalali2004, John Bowers2007,Brian Koch, Lawrence &Livermore National Labs2010.
The industrial needs of 3D laser engraving:
Laser monument system 3D can be use in different forms and shapes in industry. A 3D CAD first model is able to slice accurately as to get information of the slice that is given. So the laser beam is arranged to scan and etch the substances under profile information, generating 2D shapes of this layer. So, the Z-axis worktable lifts up with a designed to change the surface under focal plane and it starts with a new circle of cutting and laser scanning. This process will be repeated to until layers inch by inch accumulated and all model is sliced perfectly.
Now, a PC with windows 2000 can manage and control the 3D laser engraving system. The data include pictures, figures and etc that you can see on computer screen can carving by laser.
METHODS
Modeling study helps us to understand a complicated process in scientific way to study the organisms. The modeling is divided to three categories:
- Experimental or empirical models
- Analytical models
- Artificial intelligence (AI)
Experimental methods
This modeling system is based on experiments, in which the performance of a system by varying the input parameters in a given area is measured.
Mathematical model is developed using all the parameters of entry and exit from different experiments. Curve fitting techniques such as regression analysis method can be applied to develop a polynomial equation [yi ¼ f (x)] between the input factors and quality characteristics. No assumptions are made to develop these models and the model gives real solution valid for limited conditions of entry.In developing these methods, precision measuring instruments and testing is of paramount importance. The accuracy of the experiment can be increased by using scientific techniques of experimental design. Designed experiments approach is superior to the unplanned approach because it is a systematic and scientific planning experiments, collection and analysis of limited use data with resources.
Analytical methods
Laws and principles of analytical methods are based on mathematical models which can be divided into three categories, e.g. model exact solution based on model-based numerical solution, and stochastic model based solution.
Artificial intelligence (AI) methods
With the help of development expert systems AI is used in engineering problems, FL and ANN systems for predicting the behavior of the process. An expert system is an interactive program with a smart performance expert to solve a particular type of problem using the knowledge base, inference engine and user interface. Rather than operating on the net asset value, model developed under agreements with FL linguistic variables. With little human interaction ANN models are able to learn, adapt to changes and mimic the human thought process.
Usage of laser engraving in real world
Woods/Natural materials
Laser was first used for engraving images on wood by burning it. It only needs less than 10 watts to operate the laser. It produces best results on hard woods that includes oak wood, walnut woods, maple woods and mahogany woods. It is also useful to engrave images on softwoods with low power and fast speed to cut linty papers and newsprints. It works accurately on hard papers and fiberboard.
Plastics
Prior to discovery of lasers and laser technolgy plastics were engraved in different ways. After this laser technology has been introduced the method of engraving on platic is changed. Before lasers, plastic manufactures designed for rotary engraving that these drives used a mechanical rotarty spinning to cut and brush the material. Recently, the plastic manufacturers has started using the wide range of plastics with range of thickness between 0.002 to 0.003 inches. These are called laser micro plastic leminate and they offer much better engraving and cutting characteristics. These are also called as micro surface of simply burn.
Metals
For engraving metals 10,640nm wavelength CO2 laser. Using Nd: YVO4 technology at 1,064nm wavelength or its harmonics at 532 and 355nm used for new methods. Now metals can be engraved easily by using profitable systems.
Stone
There are special types of laser stones, which is better method for engraving stone materials. These laser stones are polished, very dark type, like granite, marble or basalt. White marble is also one of the excellent material for engraving which provides high quality and lightly engraved results. The more similar and fine cereal the stone have the good results with the laser engraver that achieved.
Glass
Some of the glasses products are individually amplified by laser e.g. Glasses, bottles, cups, champagne glasses, paperweights, plates, vases, ornaments. A laser can engrave messages, graphics and even photos with a powerful beam of light. The formation of a white, matte image that looks nice and professional. Although glass is sensitive material to process and the idea can be intimidating with a laser crystal, laser etching sound is one of the easiest and fastest ways to etch glass.
Cutting
It should be mentioned that same basic techniques and considerations for the production of different cut shape lasers used to establish whether in wood or in stacked fabric for clothing or even metals (plasma cutting).
Printing
Laser beam can be used by a printer which helps to create an image on a drum and lights change to the electrical charge on the drum, where it hits usually. Through a toner reservoir, this is sensed by the charged parts of the drum. The toner is transferred onto the paper using a combination of heat and pressure therefore copy machines also work like this.
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