What is a Laser Beam?

A laser beam is light amplification by stimulated emission of radiation. It allows us to perform welds, cuts, surface treatments, and drilling operations more effectively and quickly than traditional methods.

It is basically a handy tool in most branches of science related to mechanical engineering and materials processing.

What is Laser (Light Amplification by Stimulated Emission of Radiation), and Where is it used?

Fiber optic cables are used a lot in data networks because they can send data really fast.

These cables are made of delicate strands. Light pulses, which stand for the data we’re sending, move through these strands to travel across the cable.

History

When the laser was invented in 1960, people didn’t know what to use it for. The word “laser” describes devices that make a steady beam of light using something called stimulated emission. Albert Einstein figured out this idea in 1916, but it was Theodore Maiman who made the first laser in 1960.

There are lots of different kinds of lasers used in all sorts of ways. The most common ones work with atoms or groups of molecules. This creates something called population inversion, which makes the light beam. This can happen in solids, liquids, gases, or even plasma.

Also, lasers can be sorted into categories like solid-state, dye, gas, or semiconductor diode lasers. Albert Einstein’s work in 1916 started the idea for lasers, and he used Max Planck’s radiation law. In 1953, Charles H. Townes and his students made the first maser, which shoots out microwaves, unlike lasers that make visible light.

Many important events happened during laser development. In 1917, Einstein talked about something called evoked emission, which led to laser beams. In 1947, Rutherford and Lamb showed laser light for the first time. Then, in 1951, Townes and his team made the maser and got the Nobel Prize for it in 1964.

In 1958, Townes and Schawlow wrote an extensive article about how lasers could be used. Then, in 1960, Stevenson and Sorokin made the first uranium laser based on their discoveries. In 1962, semiconductor lasers were invented. Scientists found that a kind of semiconductor called gallium arsenide (GaA) could turn electricity into light.

In 1969, lasers were first used in factories to weld sheet metal in car making. Then, in 1980, physicists at Hull University found out how to make x-ray lasers. In 1985, the first CDs, which used low-power lasers to read data, were sold. This helped make music players and led to lots of semiconductor lasers for things like phones and the Internet.

Finally, in 2003, laser scanning started. This lets places like the British Museum have virtual exhibits. It also made it possible to put lots of data on DVDs or CDs.

Laser Beam Characteristics

Monochromatic light gives off electromagnetic radiation at one wavelength. Unlike regular light bulbs, it doesn’t give off many wavelengths, so it doesn’t produce heat.

The wavelength of light determines its color. White light includes all colors and is easy to see.

Laser beams have steady and precise features. They can travel long distances without losing energy.

This makes them useful for measuring the distance between the Earth and the Moon. A laser beam is sent to the Moon to get accurate measurements.

A laser beam has the same phase, frequency, and amplitude, so it stays together and travels in a straight line.

How Is Laser Formed?

Lasers are made of something called an active medium that creates the laser. Four main things happen: making the laser beam, pumping, spontaneous emission, and absorption.

Pumping uses a source like a lamp or electric current to give energy. This makes something called emission happen. Spontaneous emission is when electrons go back to their normal state. They let out light in different directions.

This makes light that’s not all the same. Excited emission happens when something outside makes the laser medium react. This makes excited atoms give off light and go back to normal. The energy from the outside thing causes this.

The light that’s given off is like the outside light in phase, energy, and direction. This makes the laser beam special. It’s consistent and all the same color. Plus, it makes more light each time it hits an excited atom.

The atoms get more energy, making them give off even more light.

Laser Beam Types

1) Ruby Laser

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.

2) Helium-Neon

Helium-Neon was the first gas laser to be built, and it is still beneficial 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.

3) Ionized Argon

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.

4) CO2 Carbon Dioxide

We can say that the CO2 carbon dioxide laser is the most critical example of a molecular laser. 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.

5) 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 power, it has become an essential alternative for some industrial applications.

6) 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.

7) Semiconductor

Semiconductor lasers have been used in many scientific-technological applications since their invention in 1962. They are the most efficient, cheapest, and most miniature lasers available today.

8) Free Electron

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 specific 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 and its ample beam power.

Thanks to the ease of automatic control and regulation of this first differentiation factor, changes and size of the surrounding material are also important.

Medical Field

In medicine, it is used effectively in the prevention of some types of diseases, with minor damage to adjacent tissues.

Therefore, it produces very few side effects in terms of irritation and inflammation of healthy tissues in its environment, and it also provides complete sterilization. It is also used to remove almost all skin defects under local anesthesia since surgical instruments are not required.

Computer Field

Among the typical applications of these systems, it is used in writing and reading digital information on barcode readers, optical storage, CDs, or DVDs.

Another example is used in copiers and printers or fiber optic communication.

Holography Field

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.

Machine Field

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.

Weld Field

It can be used in a wide variety of welding processes on metallic materials.

It was initially used in the automotive industry to combine thin sheets as a function of superficial, thermal conductivity, and beam distribution.

The lack of the use of filling material in some uses and the flexibility and ease of process control make 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 to 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 essential 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 essential in the packaging of consumer goods, can be marked.