Laser is very important technological device these days.There is a use of laser in almost every field of science and technology. It also gives it's application in medicines also.
This presentation shows how it works and what is the mechanism behind this laser phenomenon. Here it is explained from atom theory to application.
Very good explanation with photographs.
Laser is very important technological device these days.There is a use of laser in almost every field of science and technology. It also gives it's application in medicines also.
This presentation shows how it works and what is the mechanism behind this laser phenomenon. Here it is explained from atom theory to application.
Very good explanation with photographs.
Introduction to semiconductor lasers, and its working. construction of semiconductor laser, Ga As laser, and construction, achievement of population inversion, pumping.
In the world ,we see that 2 type of laser are present ,we can point with the help of laser and we can cut the metal ,but we cannot "push" ,we can develop great thing with this concept
Introduction to semiconductor lasers, and its working. construction of semiconductor laser, Ga As laser, and construction, achievement of population inversion, pumping.
In the world ,we see that 2 type of laser are present ,we can point with the help of laser and we can cut the metal ,but we cannot "push" ,we can develop great thing with this concept
A laser is a device that generates light by a process called STIMULATED EMISSION.
The acronym LASER stands for Light Amplification by Stimulated Emission of Radiation
Semiconducting lasers are multilayer semiconductor devices that generates a coherent beam of monochromatic light by laser action. A coherent beam resulted which all of the photons are in phase.
Contents
Definition of a laser
Emission and absorption of radiation
Population Inversion
Optical Feedback
Fundamentals of laser operation
Laser Hazards
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light coherently. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers. Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum, i.e., they can emit a single color of light. Temporal coherence can be used to produce pulses of light as short as a femtosecond.
Among their many applications, lasers are used in optical disk drives, laser printers, and barcode scanners; DNA sequencing instruments, fiber-optic and free-space optical communication; laser surgery and skin treatments; cutting and welding materials; military and law enforcement devices for marking targets and measuring range and speed; and laser lighting displays in entertainment.
Modern telescopes use laser technologies to compensate for the blurring effect of the Earth’s atmosphere.
Lasers are distinguished from other light sources by their coherence. Spatial coherence is typically expressed through the output being a narrow beam, which is diffraction-limited. Laser beams can be focused to very tiny spots, achieving a very high irradiance, or they can have very low divergence in order to concentrate their power at a great distance.
Temporal (or longitudinal) coherence implies a polarized wave at a single frequency whose phase is correlated over a relatively great distance (the coherence length) along the beam. A beam produced by a thermal or other incoherent light source has an instantaneous amplitude and phase that vary randomly with respect to time and position, thus having a short coherence length.
Lasers are characterized according to their wavelength in a vacuum. Most "single wavelength" lasers actually produce radiation in several modes having slightly differing frequencies (wavelengths), often not in a single polarization. Although temporal coherence implies monochromaticity, there are lasers that emit a broad spectrum of light or emit different wavelengths of light simultaneously. There are some lasers that are not single spatial mode and consequently have light beams that diverge more than is required by the diffraction limit. However, all such devices are classified as "lasers" based on their method of producing light, i.e., stimulated emission. Lasers are employed in applications where light of the required spatial or temporal coherence could not b
Able to state the definition of laser
Able to state the principle of population inversion
Able to explain the principle of semiconducting laser
Familiarise with the concept of light simulation and polarisation
Able to list down all materials criteria and materials selection for a given semiconducting laser compound.
Able to highlight several examples of the application of laser.
This belongs to Physical Chemistry portion and it contains most of
things about laser working and principles.
By Aaryan Tyagi's Group
M.Sc. Applied Chemistry (1 Sem)
Amity University, Noida
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The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
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Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
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For more information, visit-www.vavaclasses.com
1. SARVAJANIK COLLEGE OF
ENGINEERING AND
TECHNOLOGY
Physics
(2110011)
Computer Engineering – II
B.E. – I year
Topic:
Laser and its application
2. Group members
Name Roll no.
barodiya priyank 56
Vadodariya keyur 57
Jain Rishika 58
Thakur pathik 59
Patel palak 60
Patel Ishani 61
Patel Himani 62
Shah priyansh 63
Shah abhinandan 64
Khandwala mudra 65
Parmar siddhant 66
Patel harsh 67
3. Annexure
History of Laser
Characteristics of Laser
Basic Principles of Laser
ND-YAG LASER
Applications of Laser
4. What is Laser?
Light Amplification by Stimulated
Emission of Radiation
A device produces a coherent beam of optical rad
iation by stimulating electronic, ionic, or molecul
ar transitions to higher energy levels
When they return to lower energy levels by stimu
lated emission, they emit energy.
5. History of Laser
In 1917, Albert Einstein established the
theoretical foundations for the laser and
the maser in the paper Zur Quantentheorie der
Strahlung (On the Quantum Theory of
Radiation) via a re-derivation of Max Plank’s
law of radiation, conceptually based upon
probability coefficients (Einstein’s coefficient)
for the absorption, spontaneous emission, and
stimulated emission of electromagnetic
radiation.
6. In 1928, Rudolf W. Ladenburg confirmed
the existence of the phenomenon of
stimulated emission and negative
absorption. In 1939, Valentin A. Fabrikant
predicted the use of stimulated emission
to amplify "short" waves.
8. The light emitted from a laser is monochromatic,
that is, it is of one color/wavelength. In contrast,
ordinary white light is a combination of many col
ors (or wavelengths) of light.
Lasers emit light that is highly directional, that is,
laser light is emitted as a relatively narrow beam i
n a specific direction. Ordinary light, such as fro
m a light bulb, is emitted in many directions awa
y from the source
9. The light from a laser is said to be coherent, which
means that the wavelengths of the laser light are in
phase in space and time. Ordinary light can be a
mixture of many wavelengths.
The intensity of a light source is the power emitted
per unit surface area per unit solid angle. Laser is
highly intense beam
10.
11. Basic Principles of Laser
Spontaneous emission
Stimulated emission
Amplification
Population inversion
Active medium
Pumping
Optical resonators
14. Amplification
Amplification is the act or means of
increase of the physical quantity.
We can see that in stimulated
emission , there is an increase in
numbers of photons.
For amplification of light we need
stimulated emission only
15. Population inversion
Population of atoms or electrons in any
energy level is given by
In practice the population inversion is possible
when there is an existence of meta stable
state of energy.
KT
E
eNN 0
18. Active Medium
The Active medium is the solid , gas
or any solid state medium which has
meta stable state and able to create
population inversion and can amplify
the light.
19. Pumping
The processes in which the external energy is
consume to make an electron or atom to
undergo transition from low energy state to
higher one is known as pumping.
20. Types of pumping
Direct Pumping
{ Primary Pumping}
Optical electrical
Direct
conversion chemical
Indirect Pumping
{ Secondary Pumping}
21. OPTICAL PUMPING
If the luminous energy [light] is supplied to a
medium for causing population inversion , then
pumping is known as OPTICAL PUMPING
22. Electrical Pumping
The pumping by electric discharge is
preferred in the laser materials whose
higher energy levels have narrow
band width e.g. Argon ion laser.
23. Direct conversion
A direct conversion of electrical energy
to radiant energy. e.g. LED and semi
conductor laser.
24. Chemical
In the chemical pumping energy from
a chemical reaction is use for the
excitation of atoms.
25. Indirect Pumping
The later atom provide the population
inversion needed for laser emission.
X Y
26. Optical Resonator
An optical resonator is needed to build up the light
energy in the beam. The resonator is formed by placing a
pair of mirrors facing each other so that light emitted
along the line between the mirrors is reflected back and
forth. When a population inversion is created in the
medium, light reflected back and forth increases in
intensity with each pass through the laser medium.
If the laser generates a continuous beam, the amount of
light added by stimulated emission on each round trip
between the mirrors equals the light emerging in the
beam plus losses within the optical resonator
37. Applications of laser
Transmission and processing of
information
Laser scanners
Optical discs
Fibre-optic communication systems
Alignment, measurement, and imaging
Surveying
38. Industrial uses
Laser energy can be
focused in space and
concentrated in time so
that it heats, burns away,
or vaporizes many
materials. Although the
total energy in a laser
beam may be small, the
concentrated power on
small spots or during short
intervals can be
enormous.
39. Medical applications
Surgical removal of tissue with a laser is a
physical process similar to industrial laser
drilling. Carbon-dioxide lasers burn away
tissue because their infrared beams are
strongly absorbed by the water that makes
up the bulk of living cells. A laser beam
cauterizes the cuts, stopping bleeding in
blood-rich tissues such as the female
reproductive tract or the gums.
40.
41. High-energy lasers
Scientists have shown
that lasers can
concentrate extremely
high powers in either
pulses or continuous
beams. Major
applications for these
high-power levels
are fusion research,
nuclear weapons testing,
and missile defense.
