The laser beam is light amplification with exciting radiation emissions. It is essentially a very useful tool in most disciplines related to mechanical engineering and material processing, as it allows resources, cuts, surface treatments to perform drilling operations more effectively and quickly than traditional methods.
What is Laser (Light Amplification by Stimulated Emission of Radiation), and Where is it used?
Contrary to these areas, it is also widely used in data networks. It is used in fiber optic cables, a very thin cable where light pulses representing data to be sent are transmitted in the transmission medium.
When the laser was invented in 1960, it was called a solution seeking a problem to be solved, then the word laser identifies all the devices that produce a consistent beam of light as a result of an excited or stimulated emission.
This was discovered by Albert Einstein in 1916, but the first laser in the history of Modern Physics was developed by Maiman in 1960.
There are many types of lasers used in many different ways, the most common being an atom or molecule group.
In this way, the reversal of the population is created, which results in stimulated emission and electromagnetic radiation. This can exist in any solid, liquid, gas, or plasma state of the substance.
As another classification, lasers can be solid-state, dyes, gases such as semiconductor diode CO2, and electron laser.
Albert Einstein laid the foundations for developing the laser in 1916 using Max Planck’s radiation law based on the concepts of induced and self-diffusing radiation emission.
Later in 1953, Charles H. Townes and a group of graduate students came together to make the first maser. This device worked on the same physical principles as lasers but produced a microwave beam instead of a visible light beam.
There are several historical events related to the history of the laser.
In 1917, physicist Albert Einstein established the concept of evoked emission, likewise led to the development of the laser beam.
In 1947, Physicists R.C. Rutherford and Willis E. Lamb showed laser emission for the first time.
Townes appeared in 1951 with graduate assistants who invented the maser and was awarded the Nobel Prize in Physics in 1964.
In 1958, physicists Charles H. Townes and Arthur L. Schawlow were the first to publish a detailed article on optical maser applications.
In 1960, both introduced laser technology, and based on their discovery, physicists Mirek Stevenson and Peter P. Sorokin developed the first uranium laser.
In 1962, semiconductor lasers were invented. GE, IBM, and MIT Lincoln Laboratory researchers have discovered that diode devices based on gallium arsenide (GaAs) semiconductors convert electrical energy into light.
In 1969, the first industrial application of the laser was used to weld sheet metal elements in vehicle assembly.
In 1980, a group of physicists from Hull University discovered the first laser emission in the x-ray field.
In 1985, the first compact discs began to be sold everywhere, where a low power laser beam was responsible for reading the encoded and embedded data of this disc.
Then this analog signal made it possible to listen to music files and then helped produce billions of semiconductor lasers every year for use in telecommunications.
Finally, the emergence of laser scanning in 2003 allowed the British Museum to hold virtual exhibitions and record gigabytes of information into the microscopic spaces of a DVD or CD.
Monochromaticity emits electromagnetic radiation at a single wavelength, unlike sources such as incandescent lamps that emit a wider range between visible and infrared, therefore they give off heat.
The wavelength in the electromagnetic spectrum range of visible light is defined by different colors. A ray of white light is formed from all the different colors and is easily visible.
The laser beam has a consistency and addressable feature and can be projected over long distances without spreading the same amount of energy to a larger area.
Thanks to this feature, it was also used to calculate the distance between Earth and Moon by sending a laser beam to the Moon.
Since the laser beam consists of the same Phase, Frequency, and Amplitude rays, the laser beam is transmitted in parallel in one direction due to its nature.
How Is It Formed?
Generally, lasers consist of an active medium that can produce the laser.
It consists of four basic processes: laser beam, pumping, spontaneous radiation emission, excited radiation emission, and absorption.
Pumping consists of a source of radiation, such as a lamp, the passage of an electric current, or the use of any energy source that causes an emission.
Spontaneous radiation emission electrons that return to the ground state emit photons.
The resulting radiation consists of photons moving in different directions and with different phases producing inconsistent monochromatic rays.
Excited radiation emission occurs when the basis of radiation formation from a laser receives an external stimulus that causes an atom in an excited state to emit photons and thus return to a less excited state.
It is caused by the energy of a stimulating photon.
The photons emitted in this way by the excited atom have a phase, energy, and direction similar to that of the outer photon causing them, and the exciting emission is the root of the property of the laser beam.
This not only produces consistent and monochrome light but also increases light emission because another photon is produced for each photon that hits an exciting atom.
The atomic system is adapted to a higher energy state and converts an electron into a semiconductor state and competes with exciting radiation emission.
The first laser produced by Theodore Maiman in 1960 used a synthetic ruby crystal as the active medium.
Ruby is a stone formed by Al2O3 aluminum oxide crystals and containing a small concentration of about 0.05% chromium oxide Cr2O3 impurities.
The presence of chromium oxide causes the clear, pure aluminum oxide crystal to turn pink and become reddish when the chromium oxide concentration increases.
The typical geometric shape radius adopted by ruby used in a laser is cylindrical rods from 1 to 15 mm and several centimeters long.
Helium-Neon was the first gas laser to be built, and it is still very useful and very often used today.
The active centers of this laser are neon atoms, but their excitation is done through helium atoms.
A typical “He-Ne” mixture for these lasers contains one part neon and seven parts helium.
Radioactive transitions between excited gas levels date back to the 1960s.
Ionized argon lasers are widely used due to the intense emission lines and high powers available from the electromagnetic spectrum in the blue-green region.
CO2 Carbon Dioxide
We can say that 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), but transitions are carried out at the energy levels of CO2.
CO2 Dynamic Gas
The main difference between a dynamic gas laser and a conventional CO2 is the pumping method used.
Dynamic gas lasers are produced by the rapid cooling of a preheated gas mixture flowing into the resonator cavity.
Thanks to its high powers, it has become an important alternative for some industrial applications.
Organic Liquid Solution
The active medium in such lasers consists of liquids in which organic compounds are dissolved, the latter being understood as hydrocarbons and their derivatives.
These are optically pumped and one of their most important features is that they are adjustable in wide wavelength bands.
Semiconductor lasers used in many scientific-technological applications since their inventions in 1962 are the most efficient, cheapest and smallest lasers available today.
All previously seen systems base their operations on reversing the population obtained in an active atomic or molecular environment.
Therefore, the wavelength emitted by the laser is inevitably determined by the active centers located in the radiant space, that is, by the permissible energy transitions of the atoms or molecules of said medium.
Since it is not subject to the presence of certain energy transitions based on the emission of the beam induced by free electrons, and therefore the spectrum can produce electromagnetic beams at any wavelength, it does not have the limitations of the lasers seen before.
This type is called a relative electron beam as it uses an electron beam that moves at a speed close to the speed of light as the active medium.
A free-electron laser is a tool that converts the kinetic energy of a relative electron beam into a laser beam.
Where is Laser Used?
It is used in many applications where a controlled and local energy source is required due to the specific properties of the light beam with its large beam power.
Thanks to the ease of automatic control and regulation to this first differentiation factor, changes, and size of the surrounding material are also important.
In medicine, it is used effectively in the prevention of some types of diseases, with little damage to adjacent tissues.
Therefore, it produces very few side effects in terms of irritation and inflammation of healthy tissues in its environment, and also provides full sterilization and is used to remove almost all skin defects under local anesthesia, since surgical instruments are not required.
Among the common applications of these systems, it is used in writing and reading digital information on barcode reader, optical storage, CD, or DVD discs.
Holography is used to provide three-dimensional images and also as a security system for credit cards.
In holography, the waves overlap in space and merge to cancel destructive interference or to gather based on the relationship between the phases.
Due to the relationship between photons, lasers are used by interferometers and holograms.
The use of these technologies in all kinds of materials has made significant progress in the industrial world.
It is used in almost all branches as it reacts very well to the processing of materials.
In the machine field, the following works can be carried out briefly: welding, surface repair, surface design, surface coating, laser cutting, drilling, and marking.
It can be used in a wide variety of welding processes on metallic materials.
It is initially used in the automotive industry in the combination of thin sheets as a function of superficial, thermal conductivity, and beam distribution.
The lack of the use of filling material in some uses, the flexibility and ease of process control makes the laser a powerful tool for welding applications on materials that are difficult to process with other techniques.
The welding used depends on the type of materials to be welded and can be made on parts from 1 mm to 10 mm.
In addition, light-alloy welding, gold welding, and plastic material welding applications can be added to this category.
Surface Repair Field
Surface repair operations involve changing the surface properties of a material, both in terms of mechanical properties and corrosion resistance.
This also applies to metallic materials with high heat absorption and sufficient conductive heat dissipation capacity. These operations are performed with two and three-dimensional high power sources.
It is used to minimize interaction with the base material and add improved properties on the parts to create longer-lasting use.
Surface alloys form alloys on the surface of the parts to improve their thermal and mechanical properties against wear or corrosion.
Controlled thickness layers can be formed on metallic surfaces by interacting with a high-power laser with a metallic or non-metallic material.
It is used to repair damaged or worn parts by adding additional material to the material from which a part is made.
Laser Cutting Field
In laser cutting, the pressurized gas flow allows the material to be cut using the beam from the source to heat the part to the melting temperature.
Since the beam that focuses on the part has minimum dimensions, it functions as a pointed tool. For this reason, cutting operation without distortion is ensured since the thermally affected area is limited.
This process quickly cuts thin metal, wood, plastic, fabric, or ceramic layers without distortion with minimal material loss.
It also allows you to perform highly advanced and precise tasks as it cuts with very advanced precision.
It is important to check the power levels and interaction times used to accurately cut parts of a certain thickness because exceeding certain levels will cause the cut to be incorrect.
The beam, which is also used for marking, can function on the surface to be marked by applying medium force.
Using low-power equipment, data on production and consumption dates, which are important in the packaging of consumer goods, can be marked.