Lasers have revolutionized science and technology through their unique properties of being monochromatic, coherent, and able to produce high intensity, directional light. Some key applications of lasers include optical storage devices like CDs and DVDs, fiber optic telecommunications, laser printing, barcode scanning, industrial machining and welding, laser eye surgery, and 3D printing. The first laser was created in 1960 using a ruby crystal, building on the theoretical foundations laid by Einstein in 1917 regarding stimulated emission. Today, lasers come in solid state, gas, liquid, dye, and semiconductor forms and are used across fields like medicine, manufacturing, defense, holography, and more.

1. “Importance of Laser technology in the modern world”
ASSIGNMENT-2
Submitted for the course – Engineering Physics (PHY1001)
By
SAHIL JAIN
16BCE0372
Slot- C1+TC1
Name of faculty –KALAINATHAN S-SAS
(SCHOOL OF ADVANCED SCIENCES)
September, 2016

2. Introduction to LASER:-
A laser is a machine that radiates light through a process of ‘Optical amplification’ based on the
stimulated emission of ‘Electromagnetic radiation’. The phrase LASER symbolize for “light
amplification by stimulated emission of radiation”.
The progress of laser has been settled to be a turning point in the history of science and
technology. It has given the encouragement to make optics as fastest growing technology in the
today world. It has made new revolutionary systems with potential application in wide range of
fields.
History of LASER:-
The first successful laser was built by Theodore H. Maiman at Hughes Research Laboratories in
1960 using a ruby crystal.
The theoretical background of laser process as the basis for an optical amplifier was
implemented by Albert Einstein, as early as 1917, when he first predicted the presence of a
different irradiative process known as “Stimulated Emission”. His theoretical work, however
remained largely ignored till 1954, when C.H.Townes and Co-workers developed a microwave
amplifier based on stimulated emission radiation. It was known as Maser.
What Make LASER Light Different from simple Light:-
Laser light, like light from any other ordinary source, is emitted when atoms make a transition
from quantum state of higher energy to a state of lower energy. However, it has unique
properties not found in the light from any other ordinary sources.
Attributes of Laser:-
 Monochromaticity- Laser light is focused in a very thin variety of wavelengths
 Coherence- All the radiated photons carry a constant phase relationship with each other
in both time and phase.
 High Intensity- laser lights are generally low in divergence.
 Directionality- Power of EM radiation Incident per unit area.
Applications of Laser:-
Among its several applications, lasers are utilized in optical disk drives, laser printers, barcode
readers, DNA sequencing devices, fiber-optic and optical communication, laser surgeries and
skin treatments, cutting and welding materials in industries, Army and law enforcement gadgets
for pointing targets and calculating distance and speed; and laser lighting is used in many events.

3. There are 3 process of light radiation:-
Absorption
Spontaneous emission(for all lights)
Stimulated emission ( specially for Laser Light)
Stimulated Emission:-
An atom within the excited state needn’t wait for spontaneous emission to take place. If a photon
with appropriate energy (hν= E2-E1) interacts with the excited atom, it can tigger the atom to
undergo transition to the lower level and emit another photon.
The process of emission of photons by an excited atom through a forced transition occurring
under the influence of an external agent is called induced or stimulated emission.
Types of LASER:-
Solid State Laser :: Ruby Laser, Nd:YAG laser
Gas Laser :: He-Ne laser, CO2 laser, copper vapor laser
Liquid Lasers :: Se OCl2 laser
Dye Lasers :: Rhodamine 6G laser, Courmarin dye laser
Semiconductor Lasers :: Ga As laser, In p laser
RubyLaser
CO2 Laser

4. Laser applications
In Telecommunication:-
Light moves in a fiber optics glass at a velocity =c/n, where n is refractive index of glass. Light
carries information with it.
As different wavelength travel with different speeds which induce dispersion and at the receiving
end the light is observed to be spread which means loss of information or data.
However if we transfer light with more coherent beam i.e. Laser the loss can be greatly reduced
FLAG network
(Fiber-optic Link Around the Globe)
LiquidLaser
Dye Laser
He-Ne Laser
Nd-YAGLaser

5. For Medicinal Purpose:-
To destroy cancerous and precancerous cells; at the same time, the heat seal off
capillaries.
Used to break gallstones and kidney stones present in body.
To remove plaque clogging human arteries.
Fiber optic Endoscopeto find ulcers within the intestines.
Lasers are used broadly in the treatment of eye-diseases, particularly to reattach a
detached or defected retina.
The liver and lung infections could be treated using Lasers.
Bloodless surgeries are possible only because of lasers.
For Industrial/Economic Purpose:-
Lasers are used now for cutting, drilling and welding of metals and other materials.
Laser light is used to read the prefixed prices of products in shops and business
establishment from the BARCODE printed on the product.
Laser pointers are available in market for selling purpose.
For precision measurements & leveling of material in various industries.
Laser shows now a day’s earning so much money.
3-D printers also work on Laser concept.

6. In Defense and Security:-
Used in guns or arms for setting targets.
Used for night vision of military man.
Used in thermal homing missiles.
Provide Optical guidance.
It helps in blinding of troops.
It is an alternative to radar.
Used in Hellfire, Maverick, Rockeye Weapon systems.
In Holography:-
Holography is nothing but the making of holograms by the use of laser.
Possible medical applications using the holography technology:-
– Surgical process (using tracking capabilities)
– Rehabilitation techniques & Gaming

7. One Typical Application of Laser:-
The detection of the binary information keep in the type of pits on the CD is completed with the
utilization of a semiconductor laser. The laser is targeted to a diameter of regarding 0.8mm at the
lowest of the disc, however is more focused to concerning 1.7 micrometers because it passes
through the clear plastic substrate to strike the reflective layer. The reflected laser is going to
be detected by a photodiode.
Moral of the story: without optoelectronics there will no CD player!
Intro

8. THANK YOU
Sources:-
Wikipedia
Modern physics by C.Anuradha
Prof’s Class notes