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Laser is applicable in different engineering fields, for its several advantages such as:
* It is a monochromatic light.
* It has good directivity.
* It has high brightness.
* It is used in wireless connections.
By the evolution of technology, laser is widely used in many different fields.
Laser has many applications in different fields especially in engineering. It is one of the most important inventions in the last century. Laser is used widely in the engineering field providing facilities while applying many engineering processes. Its applications also helped in the development of engineering.
. Laser is an important instrument in engineering; that has been used widely by engineers in many aspects for its wide purpose and usefulness “laser is a solution looking for a problem”. This report aims to analyze the applications of laser and discuss the effect of laser on the product produced by this applications. This report gives detailed information about different engineering applications of laser.
History of Laser
"Light Amplification by the Stimulated Emission of Radiation", that's the abbreviation of the word Laser. Laser is a device that emits electromagnetic waves in the form of a special type of light. It spreads as narrow coherent beams that can be turned into one using lenses. Laser has many uses in different fields so that people needed that effective invention.
The first idea of using rays of light to help in exiting and changing the appearance of atoms was first said by Albert Einstein in 1917. He said that it would be possible to make an atom release light or make any unusual actions using rays by definite frequency. But he was not the one who invented laser itself; he just opened the way to other scientists to work on it. Schawlow and Townes are the two persons who first applied the idea of laser but they failed in their first experiment. In 1960 they succeeded to generate the first laser beam using a type of ruby.
Laser simply consists of a narrow light beam that is produced by a process called "Stimulation of atoms". This process is held by using an amplified light beam of specific frequency and intensity. That light beam is used to stimulate the atom. Stimulation of the atom means that we give it an extra amount of energy that makes in excited. That excitation makes the outer most electrons move to a higher level. Then they need to get rid of this extra energy to be back to its original and normal state, so it emits that extra energy in the form of a light beam. That light beam is laser. That's how laser is produced.
Laser solved many problems that faced engineers before inventing it. It facilitates many processes and operations for engineers. It also helps them find some information they need. As an example; before inventing laser; cutting and welding operations were very difficult. It was a problem to cut a metal, as you had to heat it up to a very high temperature then you modify its shape. Laser solved this problem and made that operation become very easy and fast. As another example; before inventing laser there were no wireless connections or laser radars. Laser also made the communication processes very fast and widely used. It made solutions for many problems that irritated engineers and people.
Laser opened a lot of knowledge and technology ways that would be impossible without it. After inventing laser it became impossible to imagine our life without it. It became the key of many engineering operations that could not be carried out without laser. Accuracy is one of its most important advantages that remove any doubts around it.
It is expected that laser will be developed more and more in the future to provide engineers by other facilities. It can also be a reason for inventing other technologies. Again, Laser can be our gate to other inventions that could make our life easier and more comfortable.
Laser Beam Welding
Laser Beam Welding “LBW” is a contemporary welding process that continues to expand into new industries and new applications because of its advantages like deep welding and reduced heat inputs. Profound Manufacturers sought to automate the welding process caused the expansion of the laser beam welding process to include computers sophisticated technology to increase the product quality and more accurate control of the welding process.
From More than 20 years ago, when laser welding was in its early stagesit was used primarily for bizarre applications where no other welding process would be suitable. Nowadays, laser welding is an imperative part of the metal toil industry.
How it works:
The Focal point is aimed on the work piece surface that weld is needed. At the surface of the work piece,the enormous concentration of light energy is transformed into thermal energy. The surface of the work piece starts melting and steps forward through it by surface conductance. For welding process, the beam energy is maintained below the vaporization temperature of the material. In Fig. 1 the laser beam is directed on the work piece.
“To the point that the laser beam contacts the work piece, all the components that direct it are transparent, refractive or reflective, absorbing only small amounts of energy from the ultraviolet light” (www.northeastlaser.com).When the pulse of laser energy is focused into a small spot at the surface of the work piece, the energy density becomes enormous. The light is engrossed by the work piece, causing a keyhole effect as the focused beam drills into, vaporizes and melts some of the metal. As described in fig. 2.C:\Documents and Settings\beso\My Documents\My Pictures\Hylas.jpg
In fig. 3 as the pulse ends, the liquefied metal around the keyhole flows back in, solidifying and creating a small spot weld, moving the work piece or the laser emitter along the surface of the work piece creates a series or spot weld that is called a seam.
Advantages of Laser Welding
One of the largest advantages that laser welding offers is the least amount of heat that is added during processing. The repeated pulsing of the beam allows for the cooling of the spot weld, resulting in a very small heat affected zone, which makes the welding process use less energy, and makes laser welding ideal for thin sections or products that require welding near electronics faultless.
In conclusion, I would say that laser beam welding process when united with robotics and computer-controlled beam movements or work piece movements make laser welding systems offer a supreme flexibility to perform a variety of operations.
3D laser scanning
3D Laser Scanning is a type of reverse engineering. Reverse engineering helps in knowing more information about any object, software, device or a system. It mainly works by analyzing any part of that object and taking it apart to know everything about it using laser. It returns that object to its origins and know how to make a copy of it without destroying the main object or modifying it. That type of engineering can be used in many fields and it can be applied on anything as it is a high quality technology. That technology depends mainly on laser and its various types. Reverse engineering analyzes objects to examine how it works or how it has been done. It also can be used to know the dimensions of a place or an object. It is mostly used on objects that it documentations are lost.
3D Laser Scanning is used to measure the dimensions of a place or a part of a place by converting physical objects or parts into data to be read on a CAD program. That measurement is done by a coordinate measuring machine that estimates accurately what are the dimensions of that part. After measuring; the CAD program draws 3D images of that part. That method helps in knowing the dimensions of the object accurately without errors or assumptions. The 3D images produced by that method are called virtual reality. Those accurate 3D images need a very large amount of data as it measures fine details of the object.
The amazing thing about 3D laser scanning is that it is supposed to take a long time to measure the fine details of an object accurately then reverse it into data that can be read by CAD programs. But actually that process takes seconds. It saves a lot of time which the person can spend to draw that object or try to measure its dimensions by any traditional method. That shows how laser helped in saving much time for engineers. Laser captures every single detail in the object in a tremendously fast and accurate way. It is impossible for human to reach that level of accuracy even if he spends hours or days trying to reach it.
3D laser scanning is applied in 3D scanners, coordinate measuring machines and 3D digitizers. As we said; it is the fastest and most accurate measuring method that can analyze objects to know how it works or to know its dimensions. Also it saves effort and money. This application is such an amazing application of laser in engineering fields. People call it “hard work that looks like magic".
A communication system is designed to transmit and receive information using light beams like fibers. Laser works as a light beams which has enormous potential for data transmission with very high data rates. Laser communications systems are wireless connections throughout the atmosphere.
Before using laser in communication, the Greeks used fire and smoke to transmit information, by the evolution of the technology, optical fibers and radio waves are used for the communication of information over distance. Nowadays, lasers are used in optic fibers communications, fibers optics is a medium for carrying information from one place to another in the form of light. Unlike the copper transmission lines, fiber optics is not electrical in nature. Communication systems are based on optical fiber because of its advantage over metallic transmission lines. Fiber optics is used increasingly in data and telecommunications. Optical data transmission is increasingly used in various areas, such as telephone, internet traffic, cable TV. In Japan, many internet connections are already delivered to home with optical fibers.
How does laser work in communication system?
Advantage of laser in communication system:
Lasers have some special characteristic such as good directivity, polarization, monochromatic, coherent.
The approach of optical fiber communications has advantages compared with systems based on electrical cables, the most important are:
* The losses for light propagation in fibers are very small because there is no fraction.
* The capacity of fibers for data transmission is huge and it's also fast in the storage of data.
* Compared with electrical cables, fiber optic cables are very light weight, so the cost is very low.
* Due to the huge transmission rate of data, the cost compared by the rate of transmission is low.
* In fibers optic cables, the problems that arise with electrical cables such as ground loops or electromagnetic interference are eliminated.
There are several significant advantages for communication system that operate with fiber optics than systems which use radio frequency:
* Laser communication provides much higher data transmission rate compared to radio frequency.
* Small dimension &light weight of components.
* Lower power.
Application of laser inspace communication:
Lasers used in free space laser communication systems, it's one of the most important application of laser in communication either semi-conductor laser diodes, solid state lasers and fibers amplifiers lasers.
Free space optical communication is the transmission of data over long distance, e.g. between:
* Earth and satellites.
* Spacecraft and Earthbased station.
There are some advantages of the use of laser in space optical communication such as: high power, large rate of data transmission, small size and light weight, but one of the main disadvantage of using laser as a link in space communication is the interconnection only between points that have direct line of sight.The application of laser communication is discussed for a global communication system and an inter-satellites link, because laser can be directed in fibers over very long distances with very low losses and avoid atmospheric influences.
CD & DVD
Laser plays an important role in our life; it has a lot of applications in a lot of fields. It is used in many fields like medical, scientific, and industrial. In this part I'll talk about some industrial uses of the laser like “CD & DVD – Holography”.
CD & DVD
We all know the importance of CDs and DVDs in our life. We use it in saving data, music albums, and videos.
CD means Compact Disk optical media that can store data, and DVD means Digital Video Disk, and it's also optical media to store data but with larger storage size, and much greater capacities.
So I can say that we have two types of disks and three types of drivers; for the disks we have CD and DVD, the difference between them would be in the storage size.
For the drivers we have CD-ROM, CD-RW, and DVD-RW. The difference between the CD-ROM and CD-RW that the CD-RW has the ability to read and write data on the CD, but CD-ROM can only read from the CD, so it's like read only memory; DVD drive can read and write on both CD and DVD disks, and has a larger storage memory than CD, so DVDs is more useful and better than CDs.
CDROM_RD.gifHow CD and DVD drivers work?
Computer takes the data from the user through keyboard, microphone, or any input device and converts it to zeros and ones. The idea is to store the data from the computer to the disks “write on the disk” using a powerful laser beam that makes holes or bumps on the disk which represents zeros and grooves that represents ones, so we can write what we want on the disk. CD and DVD the both use the same method to record data on.
To read from disk, the drive uses beam of laser that reflects back to a sensor in the drive if it hits a groove or one, but it hits a bump or zero the beam reflects with an angel and doesn't hit the sensor; through this operation the drive can read data from the disk.
Differences between CDs and DVDs:
We all already know that CDs have a storage size 700 Mega Byte, and DVDs have storage size start from 4 Giga Byte. Also DVDs could have multiple layers so its storage size could reach 17 Giga Byte, but CDs only have one layer. So we can say that CDs are much cheaper than DVDs, but DVDs are more useful, and have much greater storage size. So CDs are still preferred in publishing music albums, and DVDs are preferred in publishing movies.
Also we can say that there is a big difference between the CD and DVD drivers. We would find that the DVD drivers use a thinner beam of laser than the laser beam of CD drive so it could make smaller grooves and bumps than CD drives, so it could write on both CDs and DVDs, but CD driver could only write on CDs and can't write or read DVDs.laser.jpg
Applications of laser in communications:
Laser radar (LADAR) or (LIDAR):
Laser radar (LADAR) or (LIDAR) (Light Detection and Ranging) is similar to millimetre radar but it uses laser beams to find its target.
The (LADAR) processor looks for familiar patterns in the scenes. The processor continuously compares the scenes taken with the 3D files stored in the radar memory. It can scan large areas with very high precision and its ability to build a detailed picture of the area. The (LADAR) sensor can look at the target from different angles.
Laser radar seeker can detect objects features' with very high definition up to 15 cm resolution from about 1000 meters. After the radar identifies the object it takes a 3D picture.
Laser diode is a diode where the active medium is a semiconductor similar to light emitting diode; this diode is used to produce n-p-n or p-n-p transistors that are used widely in electronic systems, these diodes are sometimes called injection laser diodes to distinguish between optically diodes.
A laser diode is formed by doping a very thin crystal wafer on its upper surface using laser beam to produce a n type region and a p type region results in a p-n junction which is called a diode
A laser fibre is a glass or a plastic fibre that carries light through it.
These fibres are used widely in fibre-optic communications which permits transmission over long distances and at higher bandwidth than other forms of communications. Fibres are used instead of metal wires because signals travel across them with less loss and they are also immune to electromagnetic interference. Fibresare also used for illumination and sensors.
The laser microphone is a device that uses a laser beam to detect sound vibrations in distant objects.
The device takes vibrations as a pressure waves created by objects in the room (like person or an object), the laser beam is directed into the room from a window that hits the object then it returns back to the receiver that converts it to an audio signal.
The minute differences in the distance travelled by the light as it reflects from the vibrating objects (are detected interferometrically is a technique used for diagnosing two or more waves by studying the pattern of interference created by their superposition's).
A new type of laser microphones that uses laser and a smoke or vapour to detect the vibration waves in the air.
Applications of laser in computer:
Laser barcode scanner:
The laser beam bounces off a rotating mirror and scans the code, sending a modulated beam to a light detector and then to a computer which has the product information stored. Semiconductor lasers can also be used for this purpose, laser barcode scanners are the most common used barcode scanners, laser barcode scanner doesn't need to be in contact with the barcode to read it, it can read barcode 6-24 inches away from it.
A laser printer is a type of computer printers that rapidly produces high quality text and graphics on a plain paper.
It is a computer printer that uses laser beam to produce an image an on a rotating drum before transferring it to the paper.
As with digital photocopiers and multifunction printers, laser printers employ a xerographic printing process but differ from analogue photocopiers in that the image is produced by the direct scanning of laser beam across the printer photoreceptor.
A laser beam projects an image of the page to be printed onto an electrically charged rotating drum coated with selenium. Photoconductivity removes charge from area exposed to light, the drum then prints the image on a paper by direct contact and heat.
Laser printers have many advantages than other printers like the speed of laser printer can vary widely, it can print 12000 pages in one hour.
This report has discussed the applications of laser in our daily life. We have shown the different applications of laser in communication compared with different systems that operate with electrical cables & radio frequency. The application of laser in computer represented in each aspect in our daily life as laser printers, DVD and scanners. The use of laser in mechanical engineering such as welding and cutting. It is also used in measuring dimensions and analyzing object by using 3D scanning. After listing all this application and advantages of lasers. We can not neglect the present of laser in our life. By the end of the report, the benefits of laser and its applications is clear.
Laser beam welding
3D scanning: www.gks.com