Laser - applications and characteristics.



The word laser is an acronym. It stands for light amplification by stimulated emission of radiation. laser is a source of highly directional, monochromatic and coherent light. 

The working of the laser is based on the stimulated emission of radiation and population inversion.

For the stimulated emission to occur, we essentially need population inversion. To understand this term, suppose the atoms of the material can reside in three energy states I. e., Ground state E1excited state E3 and the meta stable state E2.


Remember  the atom in the excited state can stay only for 10 sec . whereas the atoms in the metastable state can stay for 10 sec.

laser , characteristics of laser
Suppose incident photons of energy hv raise the atoms from the ground state E1 to the excited state E3. But their direct decay back to E1 is prevented some how . The only alternative for the atoms in the excited state E3 is to decay to metastable state E2

We know that the life time of atoms in the excited state E3 is shorter than their life time in meta stable state  E2. Hence,  atoms reach meta stable state  E2 , much faster than they leave it. As a result, the population of atoms in the state E2 goes on increasing and at certain stage, there are more number of atoms in state  E than in state E1.

This phenomenon of making the atoms in higher energy state more than in the lower energy state by stimulated emission is called population inversion. The process by which population inversion is carried out is called optical pumping.

This population inversion is crucial for laser action. Let's now consider a situation in which a photon having an energy equal to E2 - E1 enters the system and interacts with one of the atoms in the state  E2

Due to this phenomenon, the atoms falls from the state E2 to the state E1with the release of a photon . In this case, the total number of photons will become 2. In other words, this amounts to multiplying the number of protons in the system by a factor of 2.

we therefore, have light amplification by stimulated emission of radiation or laser.

Characteristics of LASER:

1) Every laser uses an active material which converts energy into light energy.

2) The radiations of every laser is extremely intense and directional.

3) Every laser uses a feedback mechanism to provide continuous operation.

4) Every laser has a pumping source to provide power or energy. 

5) Every laser converts the beam of light into a narrow powerful cone of divergence or convergence. 

Applications of laser :

1) Surgery :

In modern medicine, lasers  are increasingly utilized for treatment of a variety of pathologies as interest in less invasive treatment modalities intensifies. The physics behind lasers allows the same basic principles to be applied to a multitude of tissue types using slight
 modifications of the system.

2) Engineering :

laser is used widely in the engineering field providing facilities while applying many engineering processes. Its applications also helped in the development of engineering.

 It is an important instrument in engineering; that has been used widely by engineers in many aspects for its wide purpose and usefulness “laser is a solution looking for a problem”.

3) Weather forecasting :

They are used in several different types of sensors. Automatic weather stations at all major airports use lasers in ceilometers to measure cloud heights and use them in a sensor that determines precipitation type. There are even some more exotic applications, such as a laser measuring wind sensor that determines rapid changes in wind speed to help wind turbine generators operate safely and efficiently.

In short, I can conclude that the development of laser technology had made our impossible things possible.

4) Military :

The invention of laser technology had made  easy for military to identify their targets which are distant from them.

Military uses of it include applications such as target designation and ranging, defensive countermeasures, communications and directed energy weapons.

There are still many applications  of it like its uses in industries, communication and computers. 


This article has fully discussed about the concept of laser ( Light Amplification by Stimulated Emission of Radiation). It also provides you information related to characteristics and applications of laser.

I hope the concept of laser ( Light Amplification by Stimulated Emission of Radiation) is now clear to you. please help others and share it on social media. Thank you for your visit. 

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