LASER Full Form - Light Amplification by Stimulated Emission of Radiation

A LASER is a special machine that makes a strong and narrow beam of light. It works by using atoms or molecules to produce light of a single colour or wavelength. This light is then made stronger or brighter. The word “LASER” stands for Light Amplification by Stimulated Emission of Radiation.

LASERs can make light in different forms, like visible light that we can see, or invisible light such as infrared and ultraviolet. There are many kinds of LASERs, and each one is made for a different use.

Full Form of LASER

The full form of LASER is Light Amplification by Stimulated Emission of Radiation.

History of LASER

The story of the LASER began in 1916 when Albert Einstein shared an idea. He said that atoms could give out light energy on their own or when another light touches them. Later, in 1928, a German scientist named Rudolf Walther Ladenburg saw this happening, but people didn’t know how to use it at that time.

In 1951, an American scientist named Charles H. Townes found a way to create this kind of light using microwaves. He built a device in 1953 that used special molecules of ammonia to produce a strong microwave signal. This device was called a maser, which means Microwave Amplification by Stimulated Emission of Radiation. Around the same time, two Russian scientists, Aleksandr Prokhorov and Nikolay Basov, also worked on the same idea. All three received the Nobel Prize in Physics in 1964.

Later, in 1957, Townes wanted to make a similar device that could work with visible light, not just microwaves. He worked with Arthur Schawlow, and they wrote about this idea in 1958. This new device was named LASER, which means Light Amplification by Stimulated Emission of Radiation. Another scientist, Gordon Gould, also had LASER ideas and wrote the word LASER for the first time. There was a long argument about who really invented the LASER, but Gould finally got patents in the 1970s and earned a lot of money.

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The First LASER

In 1960, a scientist named Theodore H. Maiman built the first real LASER. He used a crystal called synthetic ruby and a flash lamp to create red LASER pulses. This was the first working LASER ever made.

Soon after, in December 1960, Ali Javan, William Bennett Jr., and Donald Herriott built the first gas LASER using helium and neon. It produced a continuous infrared beam. Then in 1962, Robert Hall and his team made the first semiconductor LASER.

Early Uses of LASERs

At first, people didn’t know how LASERs could be useful. Some even joked that it was “a solution looking for a problem.” But slowly, scientists started finding many uses for LASERs.
In 1963, two researchers named Emmett Leith and Juris Upatnieks used LASERs to create the first 3D holograms.
The helium-neon LASER became very popular because it made a visible red beam. It was used to draw straight lines in construction, surveying, and irrigation.
Doctors also began using LASERs for eye surgeries, like fixing detached retinas without cutting the eye.

LASERs in Daily Life

In the 1970s, LASERs were used in supermarket scanners to read barcodes. After that, CD players and LASER printers were invented. Today, LASERs are used in many ways:

In presentations as LASER pointers.
In medicine to remove hair or tattoos.
In factories to cut or mark products.
In space to measure planets and asteroids.
In research labs to cool atoms to very low temperatures.

Fundamental Principles of LASERs

Lasers are special tools that give off a strong, focused beam of light. But how do they actually work? Let’s understand the basic idea:

What Makes a LASER Work?

LASERs work based on the rules of quantum mechanics, which tell us how very small particles like atoms behave. Each atom can store energy in certain fixed amounts, called energy levels.

When an atom has the least energy, it is said to be in its ground state.
When the atom gains energy, it becomes excited. But this excited state does not last long. The atom wants to return to the ground state, so it releases the extra energy as light.

How Light is Emitted in a LASER

A scientist named Albert Einstein explained that light can come out in two ways:

Spontaneous Emission: Light comes out on its own when an excited atom goes back to its ground state.
Stimulated Emission: If a light particle (called a photon) passes by and has the exact same energy, it can make the excited atom release another photon. Both light particles are exactly the same.

But usually, more atoms are in their ground state, so this process does not happen often. For LASERs to work, more atoms must be excited than in the ground state. This special condition is called population inversion.

To create this, LASERs use a light source or electric current to give energy to the atoms. This process is known as pumping.

Types of LASERs

LASERs come in many types, based on the materials used to make them. Different materials produce different types of light. Scientists use solids, gases, liquids, semiconductors, and even high-energy particles to create LASER beams. Even in space, hot gases near stars can produce LASER-like light, but they do not form proper LASER beams because they lack the special setup needed.

1. Solid-State LASERs

Solid-state LASERs use solids like crystals or glasses. These materials have small amounts of special atoms added to them. These added atoms are called dopants. When light shines on these dopants, they get excited and give off LASER light.

Ruby LASER was the first solid-state LASER, made using a crystal.
Neodymium, erbium, and ytterbium are some important dopants.
These LASERs can also be made into fibre LASERs, useful for communication and industry.
Titanium-doped sapphire can produce LASER light in many colours and is used in tunable LASERs.

2. Gas LASERs

Gas LASERs use gases to create LASER light. These LASERs are filled with gas inside a tube. An electric current passes through the gas to excite it.

The helium-neon LASER is the most popular gas LASER. It gives red light, but can also make yellow, green, orange, or infrared light.
Argon and krypton LASERs produce bright visible and ultraviolet light.
The carbon dioxide (CO₂) LASER is the most powerful commercial gas LASER. It can cut and shape materials and is used in industries.

3. Semiconductor LASERs (Diode LASERs)

Semiconductor LASERs, also called diode LASERs, are the most commonly used LASERs today. They are made using special materials known as semiconductors. When electricity flows through these materials, they produce LASER light. The light is generated at a specific part of the LASER called the p-n junction.

There are two main types of semiconductor LASERs. In edge-emitting LASERs, the light travels sideways through the junction. In VCSELs (Vertical-Cavity Surface-Emitting LASERs), the light travels up and down through the junction. These LASERs are found in devices like CD players, barcode scanners, remote controls, and many other common electronic products.

4. Dye LASERs

Dye LASERs use a liquid that contains special organic dyes. These dyes can give off many different colours of light.

The LASER colour can be changed by adjusting the setup.
Dye LASERs are used mostly in scientific experiments because they are flexible and tunable.

5. Chemical LASERs

In chemical LASERs, a chemical reaction causes the atoms to become excited. These atoms then give off LASER light.

These LASERs are powerful and used in research and defense.
They can produce a continuous and strong LASER beam.

6. Free-Electron LASERs

Free-electron LASERs are different from other types. Instead of using atoms or molecules, they use electrons moving through a special magnetic field.

The magnetic field makes the electrons give off light.
These LASERs can be adjusted to give many different wavelengths.
Some scientists say they are not true LASERs, but they still work like one and are used in high-level research.

LASER Applications

LASERs are special tools that give off strong, focused beams of light. These light beams are very clear, of one colour, and can be pointed very precisely. Even though LASERs are not used for lighting up rooms like bulbs, they are very useful when light needs to be focused on one spot or used in a specific way.

A new use of LASERs helps check if airplanes, ships, or bridges have any hidden damage in their metal parts. This can be done without taking anything apart. The LASER can find cracks or weak spots inside the metal without removing or breaking anything.

LASERs are used in many important areas. These uses can be grouped into three main types:

Sending and handling information: LASERs help in things like the internet and communication through light signals.
Delivering energy with high accuracy: LASERs are used in surgeries, cutting tools, and welding machines where energy must be sent to a small area.
Measuring, imaging, and lining things up: LASERs help measure distances, take pictures inside the body, or make sure objects are straight and in the right place.

LASERs are used in everyday life and in big industries. They help in jobs from building work to medical care and even in fun shows like LASER light displays at concerts.

Transmission and Processing of Information Using LASERs

LASERs help in sending and reading information very fast. They are used in many devices that we use in everyday life. Let’s understand some of them:

1. LASER Scanners

LASER scanners are used in shops to read barcodes on products. These scanners were first used in 1974.

A red LASER beam shines on the barcode.
A mirror moves the LASER from side to side.
When a shopkeeper moves a product across the LASER, the barcode reflects light back.
A sensor reads this light and sends the information to a computer.
The computer then shows the price of the product.

This helps in fast and accurate billing at stores.

2. Optical Discs (Like CDs and DVDs)

LASERs are used to play music, watch movies, and run computer programs on CDs and DVDs.

Inside a CD player, an infrared LASER shines on the disc.
The disc has small bumps called pits and flat parts called lands.
These small parts store the digital signals (like 0s and 1s).
A sensor reads the signals using the LASER and turns them into sound or video.

CDs were first used in the 1980s. After that came:

CD-ROMs for computers.
CD-R and CD-RW which allow users to record data.
DVDs, which store more data using a red LASER.
Blu-ray discs, which use a blue LASER and can store even more.

3. Fibre-Optic Communication Systems

LASERs are also used in modern communication systems like fibre-optic cables.

These cables have very thin glass strands.
LASER beams carry signals through these strands as light.
The signals move very fast and can go long distances.
Fibre-optic cables are used for telephone calls, internet, and other communication.

These systems are safe, fast, and secure. They do not cause electric shocks or fires.

FAQs on LASER Full Form

What is the full form of laser light amplification?

The full form is Light Amplification by Stimulated Emission of Radiation.

What is the full form of laser in radiotherapy?

In radiotherapy, LASER also means Light Amplification by Stimulated Emission of Radiation.

What is laser amplification by Stimulated Emission of radiation?

It means making light stronger using a process called stimulated emission of radiation.

What is the full form of laser?

LASER stands for Light Amplification by Stimulated Emission of Radiation.