The document discusses lasers, including their components and applications. It defines lasers as light amplification by stimulated emission of radiation. Key components include a gain medium that is pumped to excite atoms, mirrors to reflect light, and an output coupler. Laser light has properties of monochromaticity, coherence, and being highly directional. Applications include industrial uses like drilling and measurement, research, fiber optic communications, precision medicine like surgery, and everyday uses in DVD players, printers, and barcode scanners.

1. Sudhanshu Rathore – 2nd yr Electrical

2. Table Of Contents
 Introduction
 The Basics
 Absorbing Energy
 The Laser/Atom Connection
 Laser Light
 How does Laser differ from Other Light?
 Components Of Laser
 Applications Of Laser
 Everyday Applications
 Bibliography

3. Introduction
҂LASER is an acronym for
L = Light
A = Amplification
S = by Stimulated
E = Emission
R = of Radiation
҂Almost everyone probably knows that the police use
laser when they measure speed, but how many know
that you also use laser several times during an ordinary
day? You'll find it in CD players, laser printers and much,
much more.
҂The power contained in laser is both fascinating and
frightening.

4. The Basics
҂Atoms are constantly in motion. They continuously
vibrate, move and rotate.
҂Atoms can be in different states of excitation, i.e.,
they can have different energies.
҂Apply a lot of energy to an atom, it can leave what is
called the ground-state energy level and go to
an excited level.

5. Absorbing Energy
This reflects the core idea of how atoms work in terms of
lasers.
҂ Once an electron moves to a higher-energy orbit, it
eventually wants to return to the ground state.
҂ When it does, it releases its energy as a photon -- a particle
of light.
҂ For example, when the heating element in a toaster turns
bright red, the red colour is caused by atoms, excited by
heat, releasing red photons. When you see a picture on
a TV screen, what you are seeing is atoms, excited by high-
speed electrons, emitting different colours of light.
Anything that produces light -- fluorescent lights, gas
lanterns, incandescent bulbs -- does it through the
action of electrons changing orbits and releasing photons.

7. The Laser/Atom Connection
҂ A laser is a device that controls the way that
energized atoms release photons. "Laser" is an
acronym for light amplification by stimulated
emission of radiation, which describes very
succinctly how a laser works.
҂ In a laser, the lasing medium is “pumped” to get
the atoms into an excited state.
҂ The electron absorb some energy to reach this excited
level and then release this energy.

9. The Laser/Atom Connection
҂ This emitted energy comes in the form
of photons (light energy).
҂ The photon emitted has a very
specific wavelength (colour) that depends on the state
of the electron's energy when the photon is released.

11. Laser Light
Laser light has the following properties:
1. The light released is monochromatic. It contains one
specific wavelength of light (one specific colour).
2. The light released is coherent. It is “organized” -- each
photon moves in step with the others.
3. The light is very directional. A laser light has a very tight
beam and is very strong and concentrated.
To make these three properties occur takes something
called stimulated emission.

12. How Does Laser Light Differ from Other Light?
• Light is an electromagnetic wave.
• Each wave has brightness and colour, and
vibrates at a certain angle.
• This is also true for laser light but it is more
parallel than any other light source.
• Every part of the beam has (almost) the exact
same direction and the beam will therefore
diverge very little.

15. Components Of LASERS
҂ Gain medium is a material with properties that
allow it to amplify light by stimulated emission.
҂ Laser pumping energy is required for the gain
medium to amplify light. The energy is typically
supplied as an electrical current or as light at a
different wavelength.
҂ High reflector are used to bounce back and
forth the light between the mirrors, passing
through the gain medium and being amplified
each time.

16. Components Of LASERS
҂ Output coupler decides if light coming out of
the laser will be spread out or form a narrow
beam. This type of device is called as a laser
oscillator.
҂Laser beam has additional elements such as
polarization and wavelength which affect the
properties of emitted light.

17. Applications Of LASERS
1. Industrial Applications of Laser :
₪ Laser can be found in a broad range of applications within
industry, where it can be used for such things as pointing
and measuring.
₪ Within the pulp mill industry the concentration of lye is
measured by observing how the laser beam refracts in it.
₪ In the mining industry, laser is used to point out the
drilling direction.

19. Applications Of LASERS
2. Environmental Applications
ᴥ Usage to determine from a distance the
environmental toxins in a column of smoke.
ᴥ To supervise wastewater purification.

20. Applications Of LASERS
3. Research
 Extremely important to researchers within physics,
chemistry, biology and medicine, used to:
 register ultra fast chemical processes, like-bonding
between atoms to form molecules
 study the process when cells split, or a virus enters into a
cell
 manipulate molecules down to extremely low
temperatures;
 transfer as much energy as possible to different materials
in a short time to obtain different types of emissions.

22. Applications Of LASERS
4. Communications
Ѻ Works as a light source in all fibre optics in use.
Ѻ Has greater bandwidth (potentially 100,000 times greater)
than an ordinary copper cable.
Ѻ Is insensitive to interference from external electrical and
magnetic fields.
Ѻ Crosstalk (hearing someone else's phone call) is of rare
occurrence.

24. Applications Of LASERS
5. Medicine
₰ Used in medicine to improve precision work like surgery.
₰ Brain surgery is an example of precision surgery that calls
for the surgeon to reach the intended area precisely.
₰ Birthmarks, warts and discolouring of the skin can easily be
removed with an unfocused laser.
₰ Operations are quick and heal quickly and, best of all, they
are less painful

26. Everyday Applications
DVD/VCD Players
Laser Printers
Laser Pointers and Writers
Laser Sights
Speed Measurements using Laser
Laser Distance Meter
Bar Code Readers in Retail Stores
By Hunters/Shooters instead of ordinary telescope
sights

28. Bibliography
Ω www.howstuffworks.com
Ω www.nobleprize.org
Ω www.laserinternational.org
Ω www.laser.com
Ω www.hyperphysics.phy-astr.gsu.edu
Ω www.library.thinkquest.org
Ω www.xamplified.com
Ω www.wikipedia.com
Ω www.thebigger.com
Ω www.britannica.com