Laser beam

The laser or laser beam is a word derived from its acronym l ight to by mplification s timulated and mission of r adiation; that is, light amplification by stimulated emission of radiation.

Summary

[ hide ]

• 1 Importance
• 2 Introduction
• 3 Emergence
• 4 General characteristics
• 5 Physics of the laser
• 6 Types of laser
• 7 Laser applications
  • 1 In medicine
  • 2 In computing
  • 3 In holography
  • 4 In Mechanical Engineering
  • 5 laser welding
  • 6 Laser surface treatments
  • 7 Laser cutting
  • 8 Microreparation of laser molds and dies
    • 8.1 Advantages
  • 8 Other laser applications
  • 9 Interesting news
  • 10 Conclusions
  • 11 See also
  • 12 Sources

Importance

It is a very useful tool in many of the branches of science mainly related to Mechanical Engineering and for materials processing, since it allows to perform welds , cuts, surface treatments, drilling and punching in a truly efficient and faster way than those Conventional methods since it is easy to control them automatically Transmission medium commonly used in data networks; a very fine thread of transparent material, glass or plastic materials, through which pulses of light are sent that represent the data to be transmitted.

Introduction

When the laser was invented in 1960 , it was called “a solution looking for a problem to solve”, since then they have become ubiquitous, the word laser designates all those devices that generate a coherent light beam as a consequence of an induced emission or stimulated, discovered such behavior in 1916 by Albert Einstein ; although from the history of Modern Physics it is known that the first laser was developed by Maiman in 1960(using as active medium a cylindrical ruby ​​crystal). Its name is due to an acronym for the English LASER (Light Amplification by Stimulated Emission of Radiation – “Light Amplification by Stimulated Emission of Radiation”). There are numerous types of lasers that can be classified in very different ways, the most common being that which refers to its active medium or group of atoms or molecules that can be excited, so that a situation of population inversion is created, obtaining electromagnetic radiationby stimulated emission. This medium can be found in any [state] of [matter]: solid, liquid, gas or plasma. Another of the classifications refers to the fact that lasers can be of solid state, of dyes, of [gases] such as, for example, CO2; the semiconductor diode and the electron laser.

Emergence

Albert Einstein laid the foundations for developing the laser and its predecessors, the masters , in 1916 using Max Planck’s radiation [law] that is based on the concepts of induced and spontaneous radiation emission , this [theory] was forgotten until after the Second World [War]. Then in 1953 , Charles H. Townes and a group of graduate students made the first maser . This device operated using the same physical [principles] as lasers but produced a coherent microwave beam rather than a beam of light that could be seen. This Townes laser, could not operate continuously. There are several historical events that relate to the history of the laser; In 1917 , physicist Albert Einstein founded the concept of stimulated emission, the same, then gave way to the development of laser light. In 1947 , Physicists RC Rutherford and Willis E. Lamb demonstrated laser emission for the first time; Townes appeared in 1951 with his graduate assistants, who invented the maser, they were awarded the Nobel Prize in Physics in 1964 . In 1958Physicists Charles H. Townes and Arthur L. Schawlow were the first to publish a detailed article on the applications of optical masters ; in 1960 , they both introduced their laser [technology] and based on their discoveries physicists Mirek Stevenson and Peter P. Sorokin developed the first uranium laser . . In 1962 semiconductor lasers were invented . Researchers at GE, IBM and MIT’s [Lincoln Laboratory] discover that diode devices based on the gallium arsenide (GaAs) semiconductor convert electrical energy into light. In 1969, the first industrial application of the laser was discovered when it was used to weld the sheet metal elements in the assembly of vehicles. In 1980 , a group of physicists belonging to the [University] of Hull recorded the first laser emission in the field of [X-rays]. In [1985] the first compact discs began to be sold everywhere where a low [power] laser beam was responsible for reading the data that was encoded and placed inside this disc. Then that analog signal will allow you to listen to the music [files]. Billions of semiconductor lasers were manufactured each year for use in [telecommunications]. Finally in 2003, the advent of laser scanning allows the British museum to make virtual exhibitions in addition to [being able to] record gigabytes of [information] in the microscopic cavities of a [DVD] or [CD].

General characteristics

The fundamental characteristics of laser radiation are characterized by a series of properties, different from any other source of electromagnetic radiation, such as:

1. Monochromaticity Emits electromagnetic radiation of a single Wavelength, as opposed to conventional [sources] such as incandescent lamps (common bulbs) that emit in a wider range, between the visible and the Infrared , hence they give off [heat] . The wavelength, in the range of the electromagnetic spectrum of visible light, is identified by the different [colors] (red, orange, yellow, green, blue, violet), with white light being made up of all of them. This is easily seen by passing a beam of white light through a 
2. Spatial coherence or addressability Laser radiation has a very small divergence, that is, it can be projected over long distances without the beam opening or scattering the same amount of energy over a larger area. Note: This [property] was used to calculate the length between [Earth] and the Moon, by sending a laser beam towards the Moon, where it bounced off a small mirror located on its surface, and it was measured on [Earth] by a Telescope .
3. Temporal coherence The laser light is transmitted in a parallel way in a single direction due to its [nature] of stimulated radiation, since the laser beam is constituted with rays of the same Phase, Frequency and Amplitude .

Laser physics

In general, lasers consist of an active medium capable of generating the laser. There are four basic [processes] that occur in laser generation, called pumping, spontaneous radiation emission, stimulated radiation emission, and absorption. Pumping It is caused by a radiation source such as a lamp, the passage of an electric current or the use of any other type of energy source that causes an emission. Spontaneous Emission of Radiation : Electrons returning to the ground [state] emit photons . It is a random [process] and the resulting radiation is made up of photons moving in different directions and with different phases generating inconsistent monochromatic radiation. Stimulated radiation emission: Stimulated emission, the basis for the generation of radiation from a laser, occurs when an atom in an excited state receives an external stimulus that leads it to emit photons and thus return to a less excited state. The stimulus in question comes from the arrival of a photon with energy similar to the energy difference between the two states. The photons thus emitted by the stimulated atom have phase, energy and direction similar to those of the external photon that gave rise to them. The described stimulated emission is the root of many of the characteristics of laser light. It not only produces coherent and monochrome light, but also “amplifies” the light emission, since for each photon that hits an excited atom another photon is generated. Absorption: Process by which a photon is absorbed . The atomic [system] is excited to a higher energy state, passing an electron to the metastable state. This phenomenon competes with that of stimulated radiation emission.

Types of laser

1. The Ruby Laser: The first laser built by Theodore Maiman in 1960 , used as an active medium a synthetic ruby Ruby is a gemstone made of crystals of [aluminum] Al2O3 oxide, which contains a small concentration of about 0.05% of chromium oxide Cr2O3 impurities (the pure aluminum oxide, Al2O3, is called Sapphire). The presence of chromium oxide causes the clear, pure crystal of aluminum oxide to turn pink and turn reddish if the concentration of chromium oxide increases. The typical geometric shape adopted by the ruby ​​used in a laser is that of cylindrical bars 1 to 15 mm [radius] and a few centimeters long.
2. Helium-neon laser: The laser helium – neon was the first laser [gas] to be built. Today it is still very useful and is used very frequently. The [active] centers of this laser are the neon atoms, but the excitation of these is done through the helium atoms. A typical He-Ne mix for these lasers contains seven parts helium to one part neon.
3. The Ionized Argon Laser: Radioactive transitions between highly excited levels of noble [gases] have been known for a long [time], and laser oscillation in this active medium dates back to the 1960s. Among these lasers, Ionized Argon lasers are the most widely used, due to their intense emission lines in the blue-green region of the electromagnetic spectrum and the relatively high continuous [power] that can be obtained from it.
4. CO lasers: The CO2 [carbon] dioxide laser is the most important example of molecular lasers. The active medium in this laser is a mixture of carbon dioxide (CO2), nitrogen (N2) and helium (He), although the laser transitions take place at the energy levels of CO2. As we will see next, N2 and He are important for the excitation and de-excitation processes of the CO2 molecule.
5. Dynamic CO2 Gas Laser: The fundamental difference between a dynamic gas laser and a conventional CO2 laser lies in the pumping method used. In the dynamic gas laser, laser radiation is produced by rapidly cooling a preheated gas mixture that flows along a nozzle into the resonator cavity. Due to the high powers it is capable of providing, it has become an important alternative for certain industrial applications.
6. Organic liquid solutions laser: The active medium in this type of lasers is made up of liquids in which organic compounds have been dissolved, the latter being understood as [hydrocarbons] and their derivatives. These lasers are optically pumped, one of their most important characteristics is that they can emit laser radiation in wide wavelength bands, that is, they are “tunable
7. Semiconductor Lasers: [Semiconductor] lasers are the most efficient, cheapest, and smallest lasers available today. Since their invention in 1962 they have remained leaders in many scientific-technological applications and their continuous mass production indicates that this situation will continue for a long time.
8. Free electron laser: All previously seen laser [systems] base their operation on the population inversion achieved in an active atomic or molecular medium. Therefore, the wavelength at which the laser emits is inevitably determined by the active centers contained in the laser cavity, that is, by the energy transitions allowed to the atoms or molecules of said medium. A laser based on the emission of radiation stimulated by free electrons does not have the limitations of the lasers previously seen, since free electrons are not subject to the existence of particular energy transitions and therefore can generate electromagnetic radiation at any wavelength of the spectrum. This type of laser uses as an active medium an electron beam that moves with speeds close to that of light. Because of this it is called a relativistic electron beam. We can describe a free electron laser as an instrument that converts the kinetic energy of a relativistic electron beam into laser radiation.

Laser applications

Due to the particular properties of the light radiation beam with its great concentrated power (the laser), they make it an ideal tool in many applications where a controlled and localized source of energy is required. If we add to this initial differentiating factor the ease of its automatic [control] and regulation, it is observed how the field of use is extended to other uses in which precision, minimization of collateral damage and less modification of the characteristics the surrounding material and its dimensions are important. Hence the wide range of applications.

In medicine

Laser Application in Ophthalmology

The laser in medicine is increasingly used by acting very selectively on the lesion, minimally damaging the adjacent [tissues]. For this reason, it produces very few side effects in terms of destruction of other healthy tissue in its environment and inflammation, as well as presenting complete sterilization as surgical instruments are not necessary. In dermatology, they can remove almost all defects of the [skin] under local anesthesia.

• In ophthalmology, excimer lasers are used, which remove submicron layers of the cornea, modifying its curvature. The eye is transparent to light between approximately 0.38 and 1.4. At lower wavelengths the lens and corneathey absorb radiation and at higher wavelengths it is the water molecules present in the eye that absorb light. By means of laser radiation (in this case with ionized argon laser) it is now possible to treat cases of retinal detachment, where the laser beam is focused on the retina by the patient’s own lens. He-Ne lasers have been used successfully in dermatology to treat skin blemishes, or as auxiliaries to stimulate regeneration of scar tissue.
• CO2 laser in voice surgery: With the use of this method, the blood and lymphatic vessels are immediately sealed, which provides a clean operative field; saves surgical and anesthetic time. In addition, to avoid post-intervention edema and pain due to the almost zero production of thermal necrosis (death from extreme burns) of the surrounding tissues, which offers a quick recovery.
• Low-intensity laser therapy: Also called soft-laser, therapeutic laser, or low-level lasertherapy (LLLT) is a relatively recent area of ​​science. It has a wide use in current medical practice, and there are a large number of acute or chronic conditions that can be treated with this therapy, with encouraging results, far superior to those obtained with the use of conventional therapy.
• Vascular lesion laser: It is a type of laser specially designed to correct, with great effectiveness and without risk, vascular lesions such as congenital spots, telangiectasias (visible spider veins), recent stretch marks, and some scars caused by surgery, the acne or burns. The laser is an instrument that releases a large amount of energy in a very short space of time.

In computing

Application of Laser in Computation

More common applications of laser systems are, for example, the barcode reader, optical [storage] and [reading] of digital information on compact discs [(CD)] or on digital versatile discs [(DVD)] , which differs in that the latter use a shorter wavelength (they use blue instead of red laser). Other applications are laser photocopiers and [printers], or fiber optic [communications]. Applications for the near future are quantum or optical computers that will be able to process information at the [speed] of light as electrical impulses go by pulses of light provided by laser systems; many of the electronic components that [computers] have in their [structure], such as [resistors],

In holography

In holography, the [waves] overlap in space or combine to cancel (destructive interference) or to add (constructive interference) depending on the relationship between their phases. Due to the special relationship between the photons in the laser beam, lasers are considered the best known example of interference effects represented by interferometers and holograms. Holography is used to provide three-dimensional images. It is also used as a [security] system for credit [cards].

In Mechanical Engineering

Cutting of a metal

In the industrial world, there have been substantial advances in the [development] and implantation of laser technologies in all types of materials, as can be seen in Table 1. In turn, Table 2 shows the eight families of industrial applications, in which important divisions can be made in some cases, such as marking, which also includes low-power uses for marking packaging material with the [data] of the date of [preferred] consumption and manufacturing batches , a field in which facilities have multiplied in recent years. Within the materials processing, the laser is used as mentioned in all branches (cutting, [welding], microscopic marking, etc.) as it [can] be used in almost all materials and has a very good response in mechanized.

• Perform welds.
• Superficial treatments such as:
• Hardening or tempering.
• Surface alloy.
• Surface coating.
• Superficial fusion.
• Laser cut. .
• Drilling and punching.
• Marked by laser.

Materials liable to be treated by laser Metallic Carbon steels Stainless steels Tool steels Foundries Light alloys Copper alloys Titanium alloys

Non- metallic Ceramic Polymers Wood Glass Rubber Leather Cork

Laser welding

A focused laser can be used in a wide variety of welding processes, among which the most traditional is that of metallic materials. Laser welding can be done in two different ways:

• By conduction: the depth of the molten zone, initially superficial, increases as a function of thermal conductivity and the distribution of radiation intensity. This type of welding is used in the union of thin sheets.
• By deep penetration: in this type of welding it is possible to move the area of ​​greater [temperature] below the surface of the material, achieving greater performance. The molten material is displaced to the surface by the action of the superheated steam and is held there by the combined effects of gravity, viscosity and surface tension, which favors the formation of a weld bead that provides excellent mechanical characteristics to the part.

The reduced thermal impact, the lack of need to use filler material in some uses, the flexibility and ease of process control make the laser a powerful tool for welding applications on materials difficult to treat by other techniques. The welds obtained are of high [quality] metallographic and without appreciable dimensional deformations, are free of pores, cracks and bites, and have characteristics similar to conventional welding, in many cases without material input and with a process speed six times higher . The laser source used depends on the type of materials to be welded. Applications can be made on pieces with a thickness of 1 mm (it is called a “certain thickness” above 3 mm), with maximum penetrations of up to 10 mm. There is a [saving] of phases in the welding operation, since it does not affect the existing materials; therefore, it does not require subsequent treatments to eliminate tension. Welding applications with and without filler, as well as bimetal welding are widely established within the [industry]. Innovations in this field are represented by dissimilar material welding, light [alloy] welding, [gold] welding and plastic material welding applications, which are in an advanced state of development. as well as bimetal welding are widely established within the [industry]. Innovations in this field are represented by dissimilar material welding, light [alloy] welding, [gold] welding and plastic material welding applications, which are in an advanced state of development. as well as bimetal welding are widely established within the [industry]. Innovations in this field are represented by dissimilar material welding, light [alloy] welding, [gold] welding and plastic material welding applications, which are in an advanced state of development.

Surface laser treatments

One-piece wall surface treatment

Surface treatments are aimed at modifying the surface characteristics of a material, both from the point of view of its mechanical properties and corrosion [resistance]. They are applicable to metallic materials with high thermal absorption and sufficient conductive heat dissipation capacity. The surface treatments are carried out with high power laser sources in two and three dimensions. The most widespread applications in this treatment technique are the following:

• Hardening or Tempering

In this type of surface treatment, the power laser becomes a tool that, given its characteristics, allows it to act on specific areas, minimizing the interaction with the base material, and creating areas with improved characteristics on the pieces, such as an increase in the tenacity of the treated area, and the resistance to shocks and vibrations, which results in a useful life. The treated piece must not undergo subsequent transformations or manipulations, being ready for use; the process is fast and the hardness achieved is higher than that of a conventional treatment. It can be limited to specific areas of the same piece, thus achieving localized hardening.

• Alloying: The surface alloy allows the generation of alloys on the surface of the parts to improve their thermal and mechanical properties against wear or corrosion. The alloys made are specific and punctual, so it has the advantage that you really need to see their characteristics improved.
• Cladding: The surface coating involves the incorporation of material on a surface to improve its properties. By interacting a high power laser with a metallic or non-metallic powder, layers of controlled thickness can be created on metallic surfaces. The surface coatings can be made with anti-wear, anti-corrosion, special characteristics materials, etc. Confirming the required surface characteristics to the treated surface.
• Surface fusion (Melting): Another possibility lies in the reconstruction of damaged or worn parts by adding the same material in which the part is built. Likewise, the deposition layers made by applying plasma can be sealed, giving them greater adherence to the substrate and a higher degree of compactness than that obtained by the original technique. Other applications are the ablation or removal of materials adhered to substrates and the realization of structural glazes, where maximum depths of 50 mm are achieved. Another type of actions to be highlighted for its innovative component are the coatings and surface treatments of different metal components. An example is the superficial fusion of titanium in atmosphere of N2 to obtain layers of titanium nitride.

Laser cutting

Cut of a piece by LASER

In laser cutting, radiation from the laser source is used to heat the part to melting temperature, while a stream of pressurized gas drags the molten material. The use of lasers in this field offers many positive aspects. The laser beam focused on the part has minimal dimensions, so it acts as a point tool. Therefore, the thermally affected area is very limited, which avoids the appearance of distortions in parts that can have very complex contours. Laser cutting can be performed on thin sheets of metal, [wood], plastic, cloth or ceramicin short, on various materials, from [steel] to cork, through plastic materials, etc., for two and three-dimensional shapes. The laser sources used are medium and low power (from 0.4 to 1.2 kW), making it possible to make cuts in pieces with thickness ranging from 0.5 to 8mm, with tolerances between +/- 0.05 and +/- 0.1 mm.

The advantages offered by the laser over conventional techniques in this type of use are as follows: – Better use of the material, since the width of the groove generated is minimal. – The cutting walls are perpendicular to the piece and parallel to each other. – The cut piece does not require any subsequent treatment or cleaning. – You can make cuts in any direction. – The process is highly flexible and automated. – No tool changes are required, increasing equipment flexibility and [efficiency]. – It is a fast and silent process. Within this field, we can highlight the following innovative applications: – Cutting of innovative materials (Titanium and plastics). – Cut of [glass]. Although laser cutting is an investment that – well applied – provides excellent results, it can lead to serious errors if you are not properly advised. This process quickly cuts thin sheets of metal, wood, plastic, cloth, or ceramic, with minimal material loss and no distortion. At the same time, it cuts with a very high level of precision, allowing you to perform highly advanced and delicate tasks. In most glass laser applications, its use is synchronized with automatic or computerized elements such as robots. In this way the cutting of complicated designs in various materials can be done quickly and accurately. Today there are already: countless [industries] that use laser robots in their production lines, such as the electronics and automotive industries. This process quickly cuts thin sheets of metal, wood, plastic, fabric, or ceramic, with minimal material loss and no distortion. At the same time, it cuts with a very high level of precision, allowing you to perform highly advanced and delicate tasks. In most glass laser applications, its use is synchronized with automatic or computerized elements such as robots. In this way the cutting of complicated designs in various materials can be done quickly and accurately. Today there are already: countless [industries] that use laser robots in their production lines, such as the electronics and automotive industries. This process quickly cuts thin sheets of metal, wood, plastic, fabric, or ceramic, with minimal material loss and no distortion. At the same time, it cuts with a very high level of precision, allowing you to perform highly advanced and delicate tasks. In most glass laser applications, its use is synchronized with automatic or computerized elements such as robots. In this way the cutting of complicated designs in various materials can be done quickly and accurately. Today there are already: countless [industries] that use laser robots in their production lines, such as the electronics and automotive industries. allowing you to perform highly advanced and delicate tasks. In most glass laser applications, its use is synchronized with automatic or computerized elements such as robots. In this way the cutting of complicated designs in various materials can be done quickly and accurately. Today there are already: countless [industries] that use laser robots in their production lines, such as the electronics and automotive industries. allowing you to perform highly advanced and delicate tasks. In most glass laser applications, its use is synchronized with automatic or computerized elements such as robots. In this way the cutting of complicated designs in various materials can be done quickly and accurately. Today there are already: countless [industries] that use laser robots in their production lines, such as the electronics and automotive industries. Drilling and punching: The techniques used for drilling and punching are the same as those used in laser cutting (to make a cut you must make an initial drill). With these techniques maximum penetrations are achieved in pieces of considerable thickness (up to 13 mm), and diameters from 0.075 mm. To ensure correct drilling in parts of a certain thickness (above 3 mm), it is important to control the average power levels used and the interaction times, since if certain levels are exceeded, the “blowout” of the hole may be caused. The [investigations] in this field are focused on drilling with the maximum possible energy, reducing interaction times, without exploding the drilled hole, since, in practice, Marked by laser: The technique normally used for laser marking is beam displacement. With this technique a medium power laser beam is focused on the surface to be marked. The beam is oriented by a combination of galvanometric mirrors so that it follows the path of the design to be marked. Depending on the type of material to be recorded, different types of laser sources are used: CO2, Nd: YAG or excimers. Currently, a wide variety of materials can be marked: metallic materials, plastics, glass, etc. The depth of the marked area ranges from a few microns (surface marking) to tenths of millimeters (deep marking). The maximum marking surface is a 100×100 mm square.

Microreparation of molds and dies by laser

Advantage

• Minimum thermally affected area. No deformation occurs.
• Possibility of extremely fine welds with rods from 0.25 mm in diameter.
• It does not require preheating of the piece.
• Does not generate chinks.
• Minimal post-processing.
• Resulting hardnesses of 45 to 60 HRC without cracks or pores.
• Possibility of welding Aluminum and [Copper].

Other laser applications

The fusion by inertial confinement is the desired application as it would allow the development of nuclear fusion of the hydrogen in a controlled manner, allowing to obtain a very high amount of energy. This process occurs in [the Sun] and was obtained, although not in a controlled way, in 1952 , with the atomic hydrogen bomb. A laser beam can travel long distances with a small reduction in signal intensity and due to its high frequency can carry 1,000 times more information than [microwaves], making them ideal for use as a means of communication in space. . Furthermore, the laser could spell the ultimate revolution in air propulsion systems. In 2003 theNASA managed to fly indefinitely a small 300-gram plane whose energy was provided from the ground by laser. Japanese scientists did the same with a paper plane, although they used the laser to evaporate water that served as a propellant. These light aircraft could be used as alternatives to artificial satellites to establish telecommunications in areas of difficult access. But if this technology is further developed, it could mean a tremendous reduction in the ballast of conventional flights, by eliminating fuel, as already planned in space travel.. Lately, how could it be otherwise, efforts have been made to include it in military use as a substitute for conventional projectiles and missiles. There is already a prototype of an airborne laser, mounted on a Boeing 747, and the United States Air Force plans fighters armed with high-power lasers for the coming years. The first prototype, weighing just a kilowatt, weighed 750 kilograms, something perfectly adaptable to modern combat aircraft. While the large laser on board aircraft such as Boeing would serve as a precision weapon during a bombardment, the less powerful but lighter mounted fighters could be a very effective counter-weapon against missiles. Likewise, Russia has the1K17 Szhatie is a self-propelled laser tank of Russian origin. This platform uses a T-80 tank chassiswith a laser projector mounted on a turret. It was developed by the Soviet Union to combat enemy ground vehicles. The main objective of the “cannon” is to generate a laser beam that causes an alteration or damage such that it disables the optoelectronic means that the enemy uses to spot our own weapons and to guide missiles or other remotely guided weapons. In short, its use is extremely widespread and new applications are always discovered, which are always surprising, such as its participation in complex cooling processes at very low temperatures. Distance measurement with high speed and precision is another application of the laser to the military branch immediately after the laser was invented,Moon and [Earth]] (384.403 km.), With an accuracy of only 1 millimeter. It is also used to track a moving target by traveling the beam at the speed of light. Ionized argon lasers have been widely used in the study of the kinetics of chemical reactions and in the selective excitation of these. There are some chemical reactions that only occur in the presence of laser radiation or whose speed can be greatly increased when reactants are irradiated with laser light of the appropriate wavelength. In the first case we can obtain substances that would otherwise be difficult to obtain and in the second case we have the possibility of increasing the [productivity] of some chemical industries.

Interesting news

Most powerful laser beam ever created, rated at 300 terawatts

At the [University] of Michigan they have created the most powerful laser beam ever created, with a power of 300 terawatts . These kinds of “cosmic sparks” will help scientists in many fields of [science]. It was called Hercules. In other words, this powerful beam has a capacity of approximately 300 times the United States’ [electricity] [network] .

The world’s first system of cars automatically guided by laser technology, developed by Rocla Oyj, is used, for example, in paper mills. The system comprises a central control unit and automated forklift trucks that travel scheduled routes between the cargo processing points and perform lifting and [transport] tasks without an operator. Scientists, led by [professor] Gero Miesenback of the University of Oxford , remotely activated the females of a fly using a laser beam, the [neuron] that is responsible for sexual courtship in males. The result was that the female fruit fly (‘Drosophila melanogaster’) they behaved the same as the males after receiving this stimulus.

Conclusions

The scientific applications of lasers are very varied. Hardly a single [book] dedicated to this topic alone would be enough to mention them, they can be found as we have already seen, in any sector of current [society]. These include fields as disparate as consumer electronics, information technology (computing), analysis in [science], diagnostic methods in medicine, as well as machining, welding or cutting systems in industrial and military sectors. Therefore, the tasks performed by lasers go from mundane to esoteric, although they share a common element: they are difficult or totally impossible with any other instrument. Although lasers are generally relatively expensive devices, there is a large increase in their use worldwide, due to their property of supplying the shape and amount of energy required at the desired location.