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Why was the laser created? What is a laser? Working principle and application

19.10.2023

As you know, a laser is a device capable of amplifying light by stimulated emission. And the possibility of building this device was first predicted in theory, and only many years later it was possible to build the first sample. Let me remind you that stimulated emission was explained from the point of view of quantum theory by Einstein, and the first embodiment of this principle in iron began in the 50s of the twentieth century independently by various groups of scientists, the most famous of which were C. Townes, A. M. Prokhorov and N. G. Bass. Then they managed to build the first quantum generator - a maser, which generated radiation in the region of centimeter waves. At that time, the optical range remained unconquered, and I will try to tell you how it was conquered in this article.

And Theodore Maiman managed to conquer it in 1960. He carried out many calculations and came to the conclusion that a ruby crystal would be the ideal working medium for generating optical waves. He also proposed the principle of pumping the working fluid - with short flashes of light from a corresponding flash lamp and a method of creating positive feedback so that the amplifier becomes a generator - this function was performed by mirror coatings on the ends of the crystal. Meiman's calculations showed that the chromium atoms that are an impurity in sapphire crystals and make it a ruby have a suitable system of energy levels that makes the generation of laser radiation possible. Ruby implements the simplest three-level scheme. A chromium atom, absorbing light in the blue-green region of the spectrum, moves to the upper excited level, from which a non-radiative transition occurs to a metastable level, where it can linger for a time of the order of 1 ms. From this state, the atom returns to the ground level, emitting a photon with a wavelength of either 694 or 692 nm, since there is actually not one metastable level, there are two very closely located. The possibility of accumulation of atoms at a metastable level makes it possible to create an inverse population, and with it the generation of laser radiation, when one or several spontaneously emitted photons cause all other atoms to “fall apart” in an avalanche-like manner from the metastable state to the ground state, emitting new photons with the same wavelength, phase, polarization and direction of movement. They create a bright red beam, which is characterized by coherence.

The history of the invention of the first optical quantum generator is associated with many quite interesting and sometimes very unfair events. To begin with, it should be noted that Meiman carried out the development of the first laser on his own initiative and independently, only with his assistant, while the ruby laser was created contrary to the opinions of many specialists who were confident that ruby was not suitable as a working medium. There is an urban legend according to which his assistant, being colorblind, saw a red light for the first time in his life, at the moment when the laser was assembled and it started working. According to the same legend, Maiman did not observe the laser beam visually, since he was very busy setting up the recording equipment - he urgently needed to collect experimental data and prepare an article for publication, which would present convincing evidence that coherent radiation in the optical range was obtained for the first time. This is where the difficulties began. Firstly, Meiman’s article on the possible generation of optical coherent radiation in a ruby crystal was rejected from publication in the journal Physical Review Letters, specifying that “there is nothing fundamentally new in his article.” Instead, the paper was published in Nature. What is characteristic is that in 1958, the journal Physical Review Letters had already published an article on the principles of laser operation, sent from a competing organization - Bell Labs, and this despite the fact that they did not have a working copy of the laser, the article simply described a theoretical justification. They quickly concocted a patent for a laser, which they did not yet have. And Meiman received a rejection from this magazine, although he built the first working laser. Moreover, he later explained in detail to scientists from Bell Labs in a telephone conversation what was needed to create a laser and how to build it, after he had created his own. However, Maiman's priority in the invention of the laser was never recognized. And the Nobel Prize for the invention of the laser was awarded to Charles Townes, and not to him, which should have rightfully belonged to him. This is partly explained by the fact that Maiman worked for a private company that carried out orders for the military, and not in a university laboratory.

Now, let's leave the drama alone and see how Maiman's ruby laser was designed in iron. The design was extremely simple - in a compact case there was a miniature spiral flash lamp, inside which an even more miniature ruby crystal was fixed. Its opposite ends were silvered - one end was a “deaf” mirror, the second was silvered with a thinner layer that transmitted a certain amount of light. The world's first laser was 12 centimeters long, weighed 300 grams and looked like a toy.

Close-up details of the laser:

Actually, a ruby crystal.

And the entire laser is assembled, without a power source.

The press got a photo of a laser that was already larger in size, but not the first in history. And journalists immediately began to panic, saying that “death rays” had been invented.

Literally a year or two later, when the news about the invention of the laser had already spread around the world, the first laboratory samples of lasers began to appear in the USSR. Unlike Western countries, spiral pump lamps in lasers did not immediately take root. Firstly, the spiral lamp, despite its “obviousness,” has a far from optimal shape of the glow body - only a small fraction of the light goes to the address, since the adjacent turns of the spiral mainly illuminate each other, and not the ruby crystal inserted inside it. Secondly, Soviet industry did not produce a wide range of spiral flash lamps. And those that were produced had an inappropriate shape - the spiral was too large in diameter but had few turns, such as the well-known IFK-20000 and IFK-80000 lamps. There was a spiral modification of the fairly well-known and widespread IFK-2000 lamp, but it is very rare and could “pump” only the smallest ruby crystal, like Meiman’s. Since spiral lamps were rare in the USSR, they followed the path of using those lamps that were available in sufficient quantities. The first laser in the USSR had the ability to install crystals of various sizes into it, and “classical” U-shaped IFK-2000 lamps were used for pumping. This is how he looked “alive”.

And so he was shown in books by B.F. Fedorov in various publications.

Since this method of pumping still remains ineffective, it was quickly abandoned in favor of pumping with straight tubular lamps of the IFP series. Ruby crystals also began to be produced in just a few standard sizes, exactly the size of the luminous part of the lamp. The ruby crystal and the lamp began to be placed at the focal points of an elliptical reflector so that the crystal collected the maximum of available light. This is how it looks schematically.

And this is what an elliptical reflector looks like in real life.

There was also a design with a so-called “cavity” lamp. A cavity lamp is obtained by gradually increasing the number of turns in a spiral lamp to infinity until they merge into a solid cavity. This lamp consists of two quartz glass tubes nested inside one another and soldered at the ends. The electrodes are soldered into opposite ends of the lamp. The only known Soviet-made cavity lamp, IFPP-7000, was used to pump the UIG-1 laser installation.

This pumping circuit has all the disadvantages of a circuit with a spiral lamp, and therefore has not been used anywhere else. The photograph shows the IFPP-7000 lamp and the ruby crystal used with it. In addition to the now exotic schemes with spiral and cavity pump lamps, it is possible to operate a ruby laser in an even more exotic scheme - with continuous pumping. This is possible if the ruby crystal is very small, cooled with liquid nitrogen and illuminated with a focused beam from an ultra-high pressure mercury lamp or a powerful argon laser beam. But such devices never left the walls of laboratories, remaining exotic, described in scientific articles, despite the fact that over time it was possible to “wean” it off liquid nitrogen. Subsequently, mirrors sprayed onto the ends were also abandoned, since they are short-lived and if they are damaged, the entire crystal will have to be replaced. This design has been preserved only in those devices where maximum compactness is needed, such as, for example, in laser epilator emitters. In all others, the mirrors are mounted separately on adjustment devices.

It would be strange if I didn’t want to build my own ruby laser using scraps from the laser laboratory. I wanted to pay some kind of tribute to history. Well, get your first experience working with pulsed solid-state lasers. What follows is a description of building my own ruby laser.

The information is provided for informational purposes only. The author is not responsible for attempts to repeat what is described.

The basis was the above-mentioned crystal from the UIG-1 installation. This is a pale pink crystal with a working painted part size of 8*120 mm, with additional colorless tips, which gives a total crystal length of 180 mm. The tips are needed to attach the crystal to the emitter body. Another reason why the colored part is made exactly to the size of the pump lamp is that ruby has the extremely bad property of absorbing its own radiation at the lasing wavelength. If any part of the crystal remains unexposed, it begins to absorb radiation, which is amplified in the illuminated part and the laser efficiency is greatly reduced. This is due to the three-level scheme of chromium atoms in ruby. For the same reason, ruby has a very high threshold pump energy.

First of all, a prototype of the power source for the pump lamp was built. Its main part is a bank of capacitors with a capacity of 1000 μF, which was charged to a voltage of 3 kV.

Let me remind you that circuits with high-voltage capacitors of large capacity are deadly!

Lamp charging and ignition circuit. For the first attempt, IFP-5000 was taken.

First, the lamp circuit was tested without any housing. The flash of the lamp is extremely powerful, it makes a fairly loud bang and is easily visible in neighboring rooms - the light spreads through the corridor, reflecting off the walls. The flash of the lamp is capable of charring wood and paper placed directly next to it. Each flash is accompanied by the smell of burnt dust and ozone generated by a powerful pulse of hard ultraviolet light, and is accompanied by a wave of heat if you are close to it. Direct observation of the flash without eye protection is extremely dangerous! For protection, a regular welding helmet or goggles is sufficient.

Having played enough with the most powerful photoflash at that time, I assembled an emitter with this lamp and the crystal shown above. The housing for the lamp and crystal was a glass monoblock reflector from the Kvant-16 technological laser, and the warp was a piece of metal channel. Adjustment devices for the resonator mirrors were made from pieces of the same channel.

I decided to use a total reflection prism as a reflective mirror.

And as an output, a mirror supposedly from a ruby laser was chosen.
Looking ahead, I will say that this construct turned out to be unworkable. It was not possible to obtain laser generation with it. The reasons are quite obvious - the pump lamp is twice as long as the crystal and its light is used extremely inefficiently. And the ability of the output mirror to provide this generation also raised questions. Quantron (that’s what the lamp+crystal+reflector unit is called) had to be redone. In the second version, I made a new holder for the crystal and lamps; instead of one IFP5000 lamp, I decided to use two IFP2000 lamps, placed close to the crystal and connected in series electrically. The length of the IFP2000 ideally matches the length of the colored part of the crystal. This arrangement method is called “dense packing”.

It was decided to test white tiles as a reflector. The current trend in commercial laser manufacturing is the use of ceramic diffuse reflectors made from sintered alumina, which reflects up to 97% of incident light. Branded reflectors, of course, are not available to me, but the tiles look no worse, they are also perfectly white.

The output mirror was also replaced with a new one with a measured transmittance of 45% at a wavelength of 694 nm.

And in this configuration it was possible to obtain lasing from the first pulse! The lasing threshold turned out to be quite high - about 1500 J of pump energy. The laser produced a beam of deep red color, dazzling brightness. Unfortunately, due to its “transience”, it was not possible to photograph it. But we managed to record its destructive effect on metal when focusing. It produces sparks well from iron.

Since the crystal is not water-cooled, as its temperature increases, the energy of the beam drops quite quickly, until generation completely stops. And the tiles heated up well and made it difficult to remove heat. During disassembly, I noticed that the surface of the tiles began to darken. It was decided to test a metal reflector bent from a chrome plate of photo gloss.

This reflector worked the same way as tiles, but it cooled much faster and you could shoot a little more often. Several shootings were carried out on metal and rubber. The type of sparks produced depends on the type of metal. Shooting at transformer iron. It took 4 shots to get through.

Shooting at stainless steel. The sparks are brighter.

Shooting the carbon steel blade of a utility knife produces an abundance of fluffy stars.

Shooting at rubber produces a burst of flame up to 3-4 cm long, followed by rings of smoke.

It was also possible to find out that due to the use of a total reflection prism as a reflective mirror, the laser operates in a single-mode mode and produces less energy than it could at the same pump level. The fact is that the central edge of the prism is a dead zone and, based on the pattern of light rays in the total reflection prism, the light beam is split into two parallel ones, which corresponds to the TEM10 mode. This was identified by a burn mark on the black carbolite - a spot split in half, as in the picture, was clearly visible.

If you create conditions under which all other modes are not suppressed, then due to the appearance of higher modes you can achieve at least a twofold increase in the output energy. To do this, it was necessary to replace the prism, which is easily accessible, with a special reflective mirror designed to operate at a wavelength of 694 nm. And it was worth it! The generation threshold dropped to 900 J, and the energy actually increased! And when shooting at black carbolite, a uniform burn mark was obtained. Now the transformer iron plate was pierced in 2-3 shots, and the diameter of the hole turned out to be somewhat larger. Well, the number of sparks has increased significantly! It turns out especially beautiful when shooting at carbon steel.

Ordinary steel also sparks quite a bit!

3 shots make a through hole in the knife blade.

At this point, the capabilities of the laser were already clear in principle, and all that remained was to remove all that mess of capacitors and exposed high-voltage wiring into a more or less neat case, fortunately left over from the disassembled power supply of the LG-70 laser. It was decided to reduce the capacitor bank, leaving only 6 capacitors of the same type, which fit perfectly into the housing. Cramming in the rest of the junk did not cause any difficulties, there was even room left for a very important safety unit - a vacuum switch with a normally closed position, which discharges the capacitors to a powerful resistor when activities with the laser stop and the power supply is de-energized. The charge is reliably drained in about 40 seconds. The price for this was a slight decrease in radiation energy, but the pump lamps operate in a more gentle mode.

At the top are capacitors, to the right is a discharge resistor, in the lower left corner is a lamp ignition system, a round coil to the right is a ballast choke that is turned on to limit the pulse current through the lamps (without it the lamps solemnly explode after a couple of dozen flashes), even further to the right (in the center) a transformer from a Chinese microwave for charging capacitors, even to the right is its starter, and in the lower right corner is a vacuum switch BB-5, which shorts the capacitors to a resistor when the device is turned off from the network.

Rear view of the power supply unit. The fan is there simply because it was there and there was room for it. There are no actual heating units in this block. High voltage is output through two contacts on homemade bushings, which still need to be provided with additional protection from accidental touches.

After assembling the power supply, it was decided to storm the nickel, made of stainless steel approximately 1.3 mm thick. It took about 7 shots, but a through-break was obtained!

Here you can already see sparks from the back of the coin.

And here is the desired result - a through breakdown of the nickel.

To summarize, it would be strange if, with my passion, I did not build this truly outstanding type of laser, which in my implementation has an output energy estimated at 5 J using a full capacitor bank. It was with him that the history of all laser technology and a completely new science at that time began - nonlinear optics, which discovered completely unusual incidents that occur with light in the field of high powers and energies. Separately, I would like to thank Jarrod Kinsey, an American laser homemaker, with whom I was able to discuss the design of my homemade laser, and received a number of valuable comments from him. The article used materials from the following sources, in addition to the bottomless depths of the Internet:

1. B. F. Fedorov Optical quantum generators, “Energy”, 1966,
2. B. F. Fedorov Lasers and their applications, “Energy”, 1973
3. A. S. Boreysho Lasers: device and action, St. Petersburg, 1992

Thank you for reading, I hope it was interesting.

And for future projects I have a really huge ruby rod in stock - with a diameter of 16 mm and a length of the painted part of 240 mm. Total length – 300 mm. From such a crystal you can get up to 100 J of output energy. Almost what you need for a laser blaster.

Federal State Budgetary Educational Institution of Higher Professional Education

Ufa State Aviation Technical University

Creative work on history on the topic

"The History of the Laser"

Completed by: Gilmiyarov R.A. EAS 105

Checked by: Vasiliev I.M.

History of the laser

For more than half a century, lasers have been helping people in physics, medicine, chemistry, a wide variety of industries, and even in space exploration. They are used in product labeling, complex operations (for example, vision correction, which became possible only thanks to lasers), in the study of molecules, and in measuring distances in space. And even in popular culture and in everyday life! Look around you: a calendar on the wall, a CD, a glass with a beautiful engraving - all this was made using a laser.

A laser pointer, a beam that cuts iron, and an astronomical instrument that measures distances to celestial bodies are all related because they work using laser technology.

What is a laser beam? This is a light source with completely unique properties. It practically does not dissipate, but can be emitted over long distances and return back. The laser has very high heat, which allows it to cut the material it passes through.

The first steps towards this great invention of the 20th century were taken by the legendary scientist Albert Einstein. In 1917, he conducted research on stimulated emission of light, which later formed the basis of the operating principle of lasers.

The second scientist who made an important contribution to the invention was our compatriot Valentin Fabrikant. He discovered that stimulated emission can enhance electromagnetic radiation when passing through a certain medium.

Scientific background

The word “Laser” is an English abbreviation, that is, a word made up of the first letters of the phrase. “Light amplification by stimulated emission of radiation”, which translates as “light amplified by forced (or stimulated) emission of radiation” - and abbreviated as “laser”. But for the first time, the laser principle was applied not to light, but to microwaves. This discovery also belongs to our compatriots - Soviet physicists Nikolai Basov and Alexander Prokhorov. They made a report on their “molecular generator” in 1954. Two years later, the first installations were created and presented, and a directed beam of molecular waves was obtained. Technically, it was not yet a laser, but a maser (“microwave amplification by stimulated emission of radiation,” but the principle of its operation was the same.

The operation of both masers and lasers is based on the same principle, formulated in 1951 by Valentin Fabrikant. Its appearance was greeted as a technical revolution, a new era in science. At first, the laser was classified as quantum radiophysics, and later began to be called quantum electronics. However, despite the fact that the operating principles had already been formulated, the path to creating the laser took another six years. These years were filled with the search for resonators for the optical range and some other research. Scientists Basov and Prokhorov also made a great contribution to the development of the optical laser.

From 1954 to 1960, scientists conducted experiments with light waves in different environments and using different resonators. Finally, in 1960, a detailed scientific work by Nikolai Basov, Oleg Krokhin and Yuri Popov appeared, which examined the principles of operation of quantum generators (the first laser installations) and expressed the hope that they would soon be constructed. In parallel, the same in-depth work on the theory and practice of laser creation was carried out by the Americans.

First lasers

So, by the 60s, all the theoretical foundations for the operation of lasers had been laid, and scientists had only one thing left to do - to construct working models. The American Theodore Maiman succeeded in this in 1960. The first of his working prototypes worked on ruby and looked like a ruby cube with sides measuring 1 cm. Two of its sides were coated with silver (they acted as a resonator). The light was emitted by a flash lamp of enormous power. Through a small hole in one of the “silver” faces of the ruby, a thin red beam emerged. This was the world's first laser beam.

A start had been made, and then the development of lasers took huge steps. In the same year, the first gas laser installation was constructed, and a year later lasers appeared in every optical laboratory. They are studied, improved and find new applications. The next step was the creation of semiconductor lasers (1962-1963). This marked the beginning of a new era in optics and the use of lasers in all fields of science.

What types of lasers are there?

Classification of lasers and their characteristics

Lasers are distinguished by many characteristics. Here are some of the classifications:

) State of the active substance (solid, gas or liquid);

) Operating principle (amplifiers and generators);

) Method of excitation of the active substance;

) Power level

) Laser beam divergence

) Wavelength range

Lasers can use different active substances: solid (ruby, sapphire, glass), liquid, and gaseous (argon, helium). A semiconductor junction can also be used as an active substance. Accordingly, lasers are called solid-state, liquid, gas and semiconductor.

Based on their operating principle, lasers are divided into generators and amplifiers. The laser amplifier operates according to the following scheme: while it itself is in an excited state, a small signal is received at the input. This stimulates the release of energy and forms the beam.

If the laser is a generator, then the active substance is stimulated to start it. When excitement grows, at a certain moment there is a release of energy.

Excitation of the active substance can occur in different ways: due to optical radiation, electron flow, nuclear radiation, chemical or solar energy. The process can occur continuously (such devices are called “continuous wave lasers”) or intermittently (pulsed lasers)

Based on the degree of output power, lasers are distinguished between high, medium and low power.

Based on the wavelength range in which the radiation is emitted, lasers with varying degrees of monochromaticity are distinguished. It is highest for gas lasers. Solid-state lasers are not highly monochromatic because they have a significant frequency range.

The divergence of a laser beam is a parameter on which the scope of the laser depends. It's easy to understand that this is a measure of how much the beam is expanding. Gas lasers have the narrowest beam; due to this property, they are used in determining distances to a target.

The future of lasers

Despite the fact that the laser was invented more than half a century ago, it is still being improved and continues to find new applications. Currently, new laser instruments for medicine are being developed and the possibility of using laser beams in thermonuclear fusion reactions is being studied. Thermonuclear fusion is a method of producing energy similar to how it is produced by the Sun and other stars. If a reliable technology for uninterrupted thermonuclear fusion is developed, humanity will forever forget about energy shortages. Lasers are expected to play a prominent role in this discovery.

Another interesting aspect is the laser weapons. Its development has been going on for many years and there are even working prototypes - for example, hand-held laser pistols LK, created in the Soviet Union for the space industry. The main problem with such pistols is still the battery: it is impossible to choose a power source so powerful that the ray pistol is compact and not too heavy. Now, American scientists have come closest to developing military weapons capable of hitting a target with a powerful laser beam.

The development of powerful laser air defense systems was also carried out to shoot down enemy aircraft and drones with beams. Now the project continues, but has been refocused: laser air defense systems are being tested to prevent observations from space.

There are traumatic laser weapons with beams of low power but high brightness. It can temporarily blind a person. In Russia, for example, such devices are called “Potok” and are officially adopted by the Ministry of Internal Affairs. More powerful lasers, which can cause serious damage to vision, are prohibited by international law.

Low-power lasers are also used in modern weapons for precision targeting. The “red dot”, by which the film’s hero understands that a sniper has taken aim at him, is nothing more than a laser beam.

Despite so many applications in combat conditions, the laser remains primarily a peaceful weapon and is much more widely used in medicine, physics and other sciences.

Literature

laser beam wave range

1. Applications of lasers. Edited by Dr. Tech. Sciences V.P. Tychinsky, publishing house Mir, Moscow 1974.

Application of lasers in mechanical engineering and instrument making. Author: Krylov K.I., Prokopenko V.T., Mitrofanov A.S. L. Mechanical engineering. Leningrad department, 1978.

Lasers and their applications. Tarasov L.V. Textbook for vocational schools. M.: Radio and communication, 1983.

Lasers: reality and hopes. Tarasov L.V. M.: Science. Main editorial office of physical and mathematical literature, 1985.

Lasers. Basics of device and application. Fedorov B.F. M.: DOSAAF, 1988.

6. Lasers. https://ru.wikipedia.org/wiki/%CB%E0%E7%E5%F0#cite_ref-1

Purpose and scope of lasers.bibliofond.ru/view.aspx?id=41876

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Without exaggeration, the laser can be called one of the most important discoveries of the 20th century.

What is a laser

In simple words, laser is a device that creates a powerful, narrowly directed beam of light. Name "laser" ( laser) formed by adding the first letters of the words that make up the English expression l ight a mplification by s stimulated e mission of r adiation, which means "light amplification by stimulated emission". The laser creates light beams of such strength that they are capable of burning holes even in very durable materials, spending only a fraction of a second.

Ordinary light is scattered from a source in different directions. To collect it into a beam, various optical lenses or concave mirrors are used. And although such a light beam can even ignite a fire, it energy cannot be compared with the energy of a laser beam.

Laser operating principle

The physical basis of laser operation is the phenomenon forced, or induced radiation . What is its essence? What kind of radiation is called stimulated?

In a stable state, an atom of a substance has the lowest energy. This condition is considered main , and all other states - excited . If we compare the energy of these states, then in the excited state it is excess compared to the ground state. When an atom transitions from an excited state to a stable state, the atom spontaneously emits a photon. This electromagnetic radiation is called spontaneous emission.

If the transition from an excited state to a stable state occurs forcibly under the influence of an external (inducing) photon, then a new photon is formed, the energy of which is equal to the difference in the energies of the transition levels. This kind of radiation is called forced .

The new photon is an “exact copy” of the photon that caused the radiation. It has the same energy, frequency and phase. However, it is not absorbed by the atom. As a result, there are already two photons. By influencing other atoms, they cause the further appearance of new photons.

A new photon is emitted by an atom under the influence of an inducing photon when the atom is in an excited state. An atom in an unexcited state will simply absorb the inducing photon. Therefore, for light to be amplified, there must be more excited atoms than unexcited ones. This condition is called population inversion.

How does a laser work?

The laser design includes 3 elements:

1. An energy source called the laser “pumping” mechanism.

2. Laser working fluid.

3. A system of mirrors, or an optical resonator.

Energy sources can be different: electrical, thermal, chemical, light, etc. Their task is to “pump” the working body of the laser with energy in order to cause the generation of a laser light flow in it. The energy source is called mechanism"pumping" laser . It can be a chemical reaction, another laser, a flash lamp, an electric discharge, etc.

Working fluid , or laser materials , name substances that perform functions active medium. It is in the working fluid that the laser beam originates. How does this happen?

At the very beginning of the process, the working fluid is in a state of thermodynamic equilibrium, and most of the atoms are in a normal state. In order to cause radiation, it is necessary to act on atoms so that the system goes into a state population inversion. This task is performed by the laser pumping mechanism. As soon as a new photon appears in one atom, it will trigger the process of photon production in other atoms. This process will soon become an avalanche. All the resulting photons will have the same frequency, and the light waves will form a light beam of enormous power.

Solid, liquid, gaseous and plasma substances are used as active media in lasers. For example, in the first laser, created in 1960, the active medium was ruby.

The working fluid is placed in optical resonator . The simplest of them consists of two parallel mirrors, one of which is translucent. It reflects some of the light and transmits some. Reflecting from the mirrors, the beam of light returns and intensifies. This process is repeated many times. A very powerful light wave is formed at the output of the laser. There may be more mirrors in the resonator.

In addition, other devices are used in lasers - mirrors capable of changing the angle of rotation, filters, modulators, etc. With their help, you can change the wavelength, pulse duration and other parameters.

When was the laser invented?

In 1964, Russian physicists Alexander Mikhailovich Prokhorov and Nikolai Gennadievich Basov, as well as the American physicist Charles Hard Townes, became laureates of the Nobel Prize in Physics, which was awarded to them for the discovery of the principle of operation of an ammonia quantum generator (maser), which they did independently of each other. friend.

Alexander Mikhailovich Prokhorov

Nikolai Gennadievich Basov

It must be said that the maser was created 10 years before this event, in 1954. It emitted coherent electromagnetic waves in the centimeter range and became the prototype of a laser.

The author of the first working optical laser is the American physicist Theodore Maiman. On May 16, 1960, he received the first red laser beam from a red ruby rod. The wavelength of this radiation was 694 nanometers.

Theodore Maiman

Modern lasers come in a variety of sizes, from microscopic semiconductor lasers to huge, football field-sized neodymium lasers.

Applications of lasers

It is impossible to imagine modern life without lasers. Laser technologies are used in a variety of industries: science, technology, medicine.

In everyday life we use laser printers. Laser barcode readers are used in stores.

With the help of laser beams in industry, it is possible to process surfaces with the highest precision (cutting, spraying, alloying, etc.).

The laser made it possible to measure the distance to space objects with an accuracy of centimeters.

The advent of lasers in medicine has changed a lot.

It is difficult to imagine modern surgery without laser scalpels, which provide the highest sterility and cut tissue accurately. With their help, virtually bloodless operations are performed. Using a laser beam, the blood vessels of the body are cleared of cholesterol plaques. Laser is widely used in ophthalmology, where it is used to correct vision, treat retinal detachments, cataracts, etc. It is used to crush kidney stones. It is indispensable in neurosurgery, orthopedics, dentistry, cosmetology, etc.

In military affairs, laser location and navigation systems are used.

Today, various types of lasers are used in many branches of science, technology, manufacturing and medicine. Even in everyday life, we increasingly see these electronic devices. However, just some 50-60 years ago, few people knew about the laser, and the device itself, in fact, did not yet exist - there were only isolated developments in this area and the inexhaustible enthusiasm of some scientists. It was these scientists from Russia, the USA and other countries who actually stood at the origins of the history of the laser, which will be discussed in this article.

But before the appearance of the first functioning laser, there was still a fairly long history of various discoveries and inventions, which subsequently formed the basis for the invention of this device. And so, first things first.

In 1900 One of the most talented minds on our planet, the German scientist Max Planck, discovers an elementary portion of energy - a quantum and theoretically describes the connection between the energy of a quantum and the frequency of electromagnetic radiation that caused its appearance. After 8 years in 1918 He receives the Nobel Prize for his discovery. By the way, around the same time, another outstanding scientist Albert Einstein discovered the smallest elementary particle of light - the photon and proved the theory of discreteness of light.

In 1917 Einstein formulates the theory of “Stimulated Emission,” which describes the possibility of creating conditions under which electrons simultaneously emit light of the same wavelength. That is, in fact, he described the theoretical possibility of creating some kind of controlled electromagnetic emitter, later called a laser.

Only 34 years later, Einstein's idea began to turn from theory into reality. In 1951 Columbia University professor Charles Townes decides to use the theory of “stimulated emission” to create a real operating device. In 1954 He and his like-minded people Herbert Zeiger and James Gordon put their idea into practice by presenting to the public the world's first actually working laser. True, back then it was called a “maser.” The device generated a very thin beam of light at a frequency of 100 Hz with a power of 10 nW. Of course, by today's standards this is not much, but then it was a real breakthrough in optoelectronics.

One year later in 1955 Soviet scientists Alexander Prokhorov and Nikolai Basov from the Institute of Physics of the CCCP Academy of Sciences are improving the design of the maser by changing the method of pumping electrons. In 1964 In the same year, together with Townes, they received the Nobel Prize for their discoveries. In 1956 American scientist Nicholas Blumbergen from Harvard University is developing a solid-state maser. Before that, there were only gas ones.

As for the name itself, the term “laser” was first mentioned in his scientific works by a graduate of Columbia University and a colleague in scientific research of Charles Townes, Gordon Good. It happened in 1957. Why this change? The fact is that the first masers did not operate in the optical range and were invisible to the human eye. Townes developed the design of an optical light-generating device, and Good introduced the concept of “laser” and notarized the right of the first person to describe the operating principle of this device.

In 1960, American physicist Theodore Mainman creates the world's first laser, which operates on a gemstone crystal - ruby. Later, this type of lasers began to be called “ruby” and they were the most widespread for quite a long time. A little later in the same year, in November, IBM introduced its solid-state laser using 4-level pump technology.

The first commercial use of the laser occurred in 1961. At that time, there were already several companies on the market developing and producing similar optical devices. In 1962 Ruby laser was used for the first time. It was used to weld seams on the body of a wristwatch.

The first semiconductor laser was created in 1962 at General Electric. Its developer was engineer Nick Holonyak. Nowadays, lasers of this type are widely used in consumer electronics: CD players and DVD players.

This is the story!

In 1900, one of the most talented minds on our planet, the German scientist Max Planck, discovered an elementary portion of energy - a quantum and theoretically described the connection between the energy of a quantum and the frequency of electromagnetic radiation that caused its appearance. Eight years later, in 1918, he received the Nobel Prize for his discovery. By the way, around the same time, another outstanding scientist Albert Einstein discovered the smallest elementary particle of light - the photon and proved the theory of discreteness of light.

In 1917, Einstein formulated the theory of “Stimulated Emission,” which describes the possibility of creating conditions under which electrons simultaneously emit light of the same wavelength. That is, in fact, he described the theoretical possibility of creating some kind of controlled electromagnetic emitter, later called a laser.

Only 34 years later, Einstein's idea began to turn from theory into reality. In 1951, Columbia University professor Charles Townes decided to use the theory of “stimulated emission” to create a real operating device. In 1954, he and his like-minded people Herbert Zeiger and James Gordon put their idea into practice, presenting to the public the world's first actually working laser.

True, back then it was called a “maser”. The device generated a very thin beam of light at a frequency of 100 Hz with a power of 10 nW. Of course, by today's standards this is not much, but at that time it was a real breakthrough in optoelectronics.

Charles Townes (left) - inventor of the laser, who received the Nobel Prize together with Soviet scientists A. Prokhorov and N. Basov

A year later in 1955, Soviet scientists Alexander Prokhorov and Nikolai Basov from the Institute of Physics of the CCCP Academy of Sciences improved the maser design by changing the method of pumping electrons. In 1964, together with Townes, they received the Nobel Prize for their discoveries. In 1956, American scientist Nicholas Blumbergen from Harvard University develops a solid-state maser. Before that, there were only gas ones.

Professor C. Townes visiting Academician N. G. Basov

As for the name itself, the term “laser” was first mentioned in his scientific works by a graduate of Columbia University and a colleague in scientific research of Charles Townes, Gordon Good. This happened in 1957. Why this change? The fact is that the first masers did not operate in the optical range and were invisible to the human eye. Townes developed the design of an optical light-generating device, and Good introduced the concept of “laser” and notarized the right of the first person to describe the operating principle of this device.

The first Soviet ruby laser created at FIAN

The creator of the laser is academician Alexander Mikhailovich Prokhorov

The first commercial use of the laser occurred in 1961. At that time, there were already several companies on the market developing and producing similar optical devices. In 1962, the ruby laser was used for the first time. It was used to weld seams on the body of a wristwatch.

American physicist who substantiated the possibility of creating a laser, Nobel laureate Arthur Leonard Schawlow

The first semiconductor laser was created in 1962 by General Electric. Its developer was engineer Nick Holonyak.

Nick Holonyak became the father of LED technology in its current understanding.

Then laser technology developed rapidly. There appeared: gas, gas-dynamic, chemical lasers, free electron lasers, fiber lasers and others.

Helium-neon laser

Lasers are widely used in scientific measurements and experiments. They allow you to create high precision where it is needed.

Modern laser radiation sources provide experimenters with monochromatic light of virtually any desired wavelength. Depending on the task at hand, this can be either continuous radiation with an extremely narrow spectrum or ultrashort pulses with a duration of up to hundreds of attoseconds (1 as = 10−18 seconds).

The high energy stored in these pulses can be focused onto the sample under study into a spot comparable in size to the wavelength, which makes it possible to study various nonlinear optical effects. With the help of frequency tuning, spectroscopic studies of these effects are carried out, and control of the polarization of laser radiation allows for coherent monitoring of the processes under study.

Lasers are used in the information field. Laser printers and laser CD players have become part of our everyday life.

Semiconductor laser used in the image generation unit of a Hewlett-Packard printer

Lasers are used in communications, including space communications.

Laser accompaniment of musical performances (the so-called “laser show”) has become widespread.

Laser is used in construction. Laser levels, protractors and rulers allow you to take measurements with great accuracy.

Laser metal cutting is a material cutting and cutting technology that uses a high power laser and is typically used on industrial production lines. A focused laser beam, usually controlled by a computer, provides a high concentration of energy and makes it possible to cut almost any material, regardless of its thermophysical properties. During the cutting process, under the influence of a laser beam, the material of the cut area melts, ignites, evaporates or is blown away by a stream of gas.

In this case, it is possible to obtain narrow cuts with a minimal heat-affected zone. Laser cutting is characterized by the absence of mechanical impact on the material being processed; minimal deformations occur, both temporary during the cutting process and residual after complete cooling. As a result, laser cutting, even easily deformable and non-rigid workpieces and parts, can be carried out with a high degree of accuracy.

Lasers are widely used in medicine. With the advent of industrial lasers, a new era in surgery has begun. In this case, the experience of specialists in laser metal processing came in handy. Laser welding of a detached retina is spot contact welding; laser scalpel - autogenous cutting; welding of bones - fusion butt welding; joining muscle tissue is also resistance welding.

Since the mid-50s of the 20th century, large-scale work has been carried out in the USSR to develop and test high-power laser weapons as a means of directly hitting targets in the interests of strategic anti-space and missile defense. Among others, the Terra and Omega programs were implemented. Laser testing was carried out at the Sary-Shagan test site (air defense, missile defense, PKO, SKKP, early warning system) in Kazakhstan. After the collapse of the Soviet Union, work at the Sary-Shagan test site was stopped.

In mid-March 2009, the American corporation Northrop Grumman announced the creation of a solid-state electric laser with a power of about 100 kW. The development of this device was carried out as part of a program to create an effective mobile laser system designed to combat ground and air targets.