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

1. A
Paper on....
Laser Technology In Modern
Trend.
Submitted by...
Mr.Mandar pathrikar
Mob no.9604725590
mandarpathrikar@yahoo.com
First Year Engineering
Imperial College Of Engineering & Research,
Gat No. 720/1&2, Wagholi, Nagar Road.
Pune-421 207
-:Under kind Guidance of:-
Mrs.Prof. prajakta dhole (electronics)
: Mr.waghchavre . (physics)

2. Abstract
Laser technology is the one of the
best & pe globally spread type of
technology.most of the device are
made up of laser principle .In the x-
ray this technique is used to
stimulate the light for production
.Laser is used in the medical as
well as in the engineering field for
various purpose.
Introduction
“LASER” we can simply define as
“Light Amplification by stimulated
emission of Radiation”
A laser is a device that emits light
(electromagnetic radiation) through
a process of optical amplification
based on the stimulated emission of
photons.
The term "laser" originated as an
acronym for Light Amplification
by Stimulated Emission of
Radiation. The emitted laser light is
notable for its high degree of
spatial and temporal coherence,
unattainable using other
technologies.
Temporal (or longitudinal)
coherence implies a polarized wave
at a single frequency whose phase
is correlated over a relatively large
distance (the coherence length)
along the beam.
A beam produced by a thermal or
other incoherent light source has an
instantaneous amplitude and phase
which vary randomly with respect
to time and position, and thus a
very short coherence length.
History
In 1917, Albert Einstein established
the theoretic 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 Planck’s
law of radiation, conceptually
based upon probability coefficients
(Einstein coefficients) for the
absorption, spontaneous emission,
and stimulated emission of
electromagnetic radiation; in 1928,
In 1957, Charles Hard Townes and
Arthur Leonard Schawlow, then at

3. Bell Labs, began a serious study of
the infrared laser. As ideas
developed, they abandoned infrared
radiation to instead concentrate
upon visible light.
1.HOW TO PRODUCE
LASER
We know that on the theory of
Einstein ,we can produce the laser
waves.
Laser is a device for producing a
highly intense narrow beam of
nearly
monochromatic light. Laser light
can travel large distances without
spreading and is capable of being
focused to give enormous power
density as high as 108 Watt/cm2.
power density is the energy
incident on unit area in one second.
When an electron from an orbit of
higher energy (E2) jumps to an
orbit of lower energy (E1), a
photon of energy = (E2 – E1)= hv
is emitted, where v is the frequency
of the photon emitted. As this takes
place spontaneously, it is called
spontaneous emission.
If a photon of proper energy falls
on an atom, it may be absorbed
completely and an electron of the
atom in a lower energy state may
be raised to a higher energy state.
This process is called excitation.
Electron at initial energy level
In addition to the above two
processes there is another process.
An electron in a higher energy level
may remain in that level for
sometime. If another photon of
energy hv=(E2 – E1) is incident on
it, then the electron in the higher
energy level is made to jump to the
lower energy level emitting a
photon of exactly the same
frequency as the incident photon
(figure). This type of emission is
called stimulated emission.
Incident photon is the stimulating
photon and the emitted one due to
this, is the stimulated photon. The
emitted photon is exactly in phase
with the stimulating photon. This
makes the laser action possible.
Thus, two identical photons are
produced in stimulated emission.
. The process of raising atoms from
lower energy levels to higher
energy levels is called population
inversion. Population inversion is
achieved by supplying energy from

4. external sources. The process of
supplying energy from an external
source, to achieve population
inversion in a system, is called
optical pumping.
Once population inversion is
attained to sufficient extent, laser
process is started by a stray photon
of suitable energy.
Photon amplification takes place
by stimulated emission. These
photons are made to come out in
the same direction as a narrow
beam.
1.1 design of laser
beam
Principal components:
1. Gain medium
2. Laser pumping energy
3. High reflector
4. Output coupler
5. Laser beam
A laser consists of a gain medium
inside a highly reflective optical
cavity, as well as a means to supply
energy to the gain medium. The
gain medium is a material with
properties that allow it to amplify
light by stimulated emission. In its
simplest form, a cavity consists of
two mirrors arranged such that light
bounces back and forth, each time
passing through the gain medium.
Typically one of the two mirrors,
the output coupler, is partially
transparent. The output laser beam
is emitted through this mirror.
Light of a specific wavelength that
passes through the gain medium is
amplified (increases in power); the
surrounding mirrors ensure that
most of the light makes many
passes through the gain medium,
being amplified repeatedly. Part of
the light that is between the mirrors
(that is, within the cavity) passes
through the partially transparent
mirror and escapes as a beam of
light.
The process of supplying the
energy required for the
amplification is called pumping.
The energy is typically supplied as
an electrical current or as light at a
different wavelength. Such light
may be provided by a flash lamp or
perhaps another laser. Most
practical lasers contain additional
elements that affect properties such
as the wavelength of the emitted
light and the shape of the beam.

5. 1.2 Ruby laser tube
2. Types of laser
1.Gas laser
Following the invention of the
HeNe gas laser, many other gas
discharges have been found to
amplify light coherently. Gas lasers
using many different gases have
been built and used for many
purposes. The helium-neon laser
(HeNe) is able to operate at a
number of different wavelengths,
however the vast majority are
engineered to lase at 633 nm; these
relatively low cost but highly
coherent lasers are extremely
common in optical research and
educational laboratories.
Commercial carbon dioxide (CO2)
lasers can emit many hundreds of
watts in a single spatial mode
which can be concentrated into a
tiny spot. This emission is in the
thermal infrared at 10.6 µm; such
lasers are regularly used in industry
for cutting and welding.
The efficiency of a CO2 laser is
unusually high: over 10%. Argon-
ion lasers can operate at a number
of lasing transitions between 351
and 528.7 nm. Depending on the
optical design one or more of these
transitions can be lasing
simultaneously; the most
commonly used lines are 458 nm,
488 nm and 514.5 nm.
2. Chemical lasers
Chemical lasers are powered by a
chemical reaction permitting a
large amount of energy to be
released quickly. Such very high
power lasers are especially of
interest to the military, however
continuous wave chemical lasers at
very high power levels, fed by
streams of gasses, have been
developed and have some industrial
applications. As examples, in the
Hydrogen fluoride laser (2700-
2900 nm) and the Deuterium
fluoride laser (3800 nm) the
reaction is the combination of
hydrogen or deuterium gas with
combustion products of ethylene in
nitrogen trifluoride.
3. Solid-state lasers
A frequency-doubled green laser
pointer, showing internal
construction. Two AAA cells and
electronics power the laser module
(lower diagram) This contains a
powerful 808 nm IR diode laser
that optically pumps a Nd:YVO4
crystal inside a laser cavity. That

6. laser produces 1064 nm (infrared)
light which is mainly confined
inside the resonator. Also inside the
laser cavity, however, is a non-
linear KTP crystal which causes
frequency doubling, resulting in
green light at 532 nm. The front
mirror is transparent to this visible
wavelength which is then expanded
and collimated using two lenses (in
this particular design).
Solid-state lasers use a crystalline
or glass rod which is "doped" with
ions that provide the required
energy states. For example, the first
working laser was a ruby laser,
made from ruby (chromium-doped
corundum). The population
inversion is actually maintained in
the "dopant", such as chromium or
neodymium. These materials are
pumped optically using a shorter
wavelength than the lasing
wavelength, often from a flashtube
or from another laser.
It should be noted that "solid-state"
in this sense refers to a crystal or
glass, but this usage is distinct from
the designation of "solid-state
electronics" in referring to
semiconductors. Semiconductor
lasers (laser diodes) are pumped
electrically and are thus not
referred to as solid-state lasers. The
class of solid-state lasers would,
however, properly include fiber
lasers in which dopants in the glass
lase under optical pumping. But in
practice these are simply referred to
as "fiber lasers" with "solid-state"
reserved for lasers using a solid rod
of such a material.
3. Different applications
need lasers with different
output powers.
Lasers that produce a continuous
beam or a series of short pulses can
be compared on the basis of their
average power. Lasers that produce
pulses can also be characterized
based on the peak power of each
pulse. The peak power of a pulsed
laser is many orders of magnitude
greater than its average power. The
average output power is always less
than the power consumed.
The continuous or average power
required for some uses:
• 1-5 mW – laser pointers
• 5 mW – CD-ROM drive
• 5–10 mW – DVD player or
DVD-ROM drive
• 100 mW – High-speed CD-
RW burner
• 250 mW – Consumer DVD-
R burner
• 1 W – green laser in current
Holographic Versatile Disc
prototype development
• 1–20 W – output of the
majority of commercially
available solid-state lasers
used for micro machining
• 30–100 W – typical sealed
CO2 surgical lasers[28]
• 100–3000 W – typical
sealed CO2 lasers used in
industrial laser cutting
• 1 kW – Output power
expected to be achieved by
a prototype 1 cm diode laser
bar[29]
• 100 kW – Claimed output
of a CO2 laser being

7. developed by Northrop
Grumman for military
(weapon) applications.
3. MEDICAL
APPILCATION OF
LASER
In the medical field also there is
very importance of laser
technology.because this waves are
highly coherent , monocromatic
&having highly focused
wavelength from the graph we ca
easily identify the flow of the blood
capuscals
From the figure we can say that
The white blood cells have definite
path & structure in the normal
method this wave is not see as
much as clear but with the laser
theropy can show it in clear form.
As well as in the red blood
carpuscals have low in number but
presence of it we can see in
accurate sinusoidle wave form.
4.Laser weapons
Laser beams are famously
employed as weapon systems in
science fiction, but actual laser
weapons are still in the
experimental stage.
The general idea of laser-beam
weaponry is to hit a target with a
train of brief pulses of light. The
rapid evaporation and expansion of
the surface causes shockwaves.
that
damage the target.
The power needed to project a
high-powered laser beam of this
kind is beyond the limit of current
mobile power technology thus
favoring chemically powered gas
dynamic lasers.
Lasers of all but the lowest powers
can potentially be used as
incapacitating weapons, through
their ability to produce temporary
or permanent vision loss in varying
degrees when aimed at the eyes.

8. The degree, character, and duration
of vision impairment caused by eye
exposure to laser light varies with
the power of the laser, the
wavelength(s), the collimation of
the beam, the exact orientation of
the beam, and the duration of
exposure
. The extreme handicap that laser-
induced blindness represents makes
the use of lasers even as non-lethal
weapons morally controversial, and
weapons designed to cause
blindness have been banned by the
Protocol on Blinding Laser
WeaponsIn the field of aviation, the
hazards of exposure to ground-
based lasers deliberately aimed at
pilots have grown to the extent that
aviation authorities have special
procedures to deal with such
hazards.[34]
On March 18, 2009 Northrop
Grumman claimed that its
engineers in Redondo Beach had
successfully built and tested an
electrically powered CO2 laser
capable of producing a 100-
kilowatt beam, powerful enough to
destroy an airplane or a tank
. According to Brian Strickland,
manager for the United States
Army's Joint High Power Solid
State Laser program, an electrically
powered laser is capable of being
mounted in an aircraft, ship, or
other vehicle because it requires
much less space for its supporting
equipment than a chemical laser.
However the source of such a large
electrical power in a mobile
application remains unclear.
5. CNC Lasers
At World Machinery we supply
both new and used sheet metal
fabrication machinery and
equipment.
We specialise in laser cutting
machines, CNC punch and turret
presses, plasma and waterjet cutting
machines along with pressbrakes
and sheetmetal guillotines. We can
supply both new and used
equipment anywhere in the world.
We have specialist engineers who
can advise you on the suitability of
all equipment for your application
and our installation engineers will
fully commission your equipment
before handover when required and
all machines can be seen under
power if required at our extensive
showroom and warehouse facilities.
5.1 Laser Cutting Methods
Depending on the material to be cut
the cutting methods used differ :
Fusion Cutting ( high pressure
cutting):

9. • The material is fused by the
energy of the laser beam.
• The gas, in this case
nitrogen at high pressure
(10 to 20 bar), is used to
drive out the molten
material from the kerf.
• The gas also protects the
focusing from splashes
Oxidation Cutting (laser torch
cutting):
• The material is heated by
the laser beam to
combustion temperature.
• The gas, in this case oxygen
at a medium pressure (0.4 to
5 bar) is used to oxidize the
material and to drive the
slag out of the kerf.
• The gas also protects the
focusing optics from
splashes.
• The exothermic reaction of
the oxygen with the
material supplies a large
part of the energy for the
cutting process.
This cutting method is the quickest
and is used for the economical
cutting of carbon steels.
5.2 Parameters Affecting Laser
Cutting
• Laser power
• Pulse frequency
• Type and pressure of
cutting gas
• Distance between the
cutting nozzle and the
work-piece
• Cutting speed
• Acceleration
• Material
• Work-piece surface
• Work-piece shape
1 = Laser beam
2 = Cutting gas
3 = Focusing lens
4 = Cutting head / nozzle
5 = Work-piece
6 = Blow-out molten mass

10. CONCLUSION
Advantages of laser
technology
Laser technology has the following
advantages:
• High accuracy
• Excellent cut quality
• High processing speed
• Small kerf
• Very small heat-affected
zone compared to other
thermal cutting processes
• Very low application of
heat, therefore minimum
shrinkage of the cut
material
• It is possible to cut complex
geometrical shapes, small
holes, and beveled parts
• Cutting and marking with
the same tool
• Cuts many types of
materials
• No contact between the
material and machining tool
(focusing head) and
therefore no force is applied
to the work-piece
• Easy and fast control of the
laser power over a wide
range (1-100%) enables a
power reduction on tight or
narrow curves
• The oxide layer is very thin
and easily removed with
laser torch cutting
• High-pressure laser cutting
with nitrogen enables oxide-
free cutt
REFERENCES
1. MR. Waghchavre , F.E.
physics lecturer & MSC
(physics).
2. physics textbook of “ TEX-
MAX”
3. Book written by
V.K.Walekar,Dr.K.C.
Nandi,& S.N.Shukla.