LASER
Prepared By :-
Rushit Patel

L Light
A Amplified by
S Stimulated
E Emission of
R Radiation

What Is LASER?
 A LASER is a device that
transforms light of various
frequencies into a chromatic
radiation in the visible,
infrared, and ultraviolet
regions with all waves in
phase capable of transferring
immense Heat and power
when focused at close range.

INVENTORS OF LASER
Theodore Harold Maiman

Charles Townes
it was based on Einstein’s idea of the “particle
wave duality” of light
Originally called MASER

Coherent And Incoherent
Light

AMPLIFICATION
 Is a part of a process that occurs inside the
laser.
 An optical cavity is at the center of the laser
device & the core is comprised of chemical
elements, molecules or compounds –
“Active Medium”
 Lasers are generically named for the
material of the active medium

Laser
Delivery
System
Hollow
Waveguide
or Tube
Glass fiber
optic cable

Hollow Waveguide or Tube
 Has an interior finish mirror
 Laser energy is reflected along this tube
and exits through a hand piece
 Strikes the tissue in a non-contact manner
 An accessory tip of sapphire or hollow
metal can be connected

Glass fiber Optic Cable
 More flexible than waveguide
 Less weight and less resistance in
movement
 Smaller diameter (200-600 μm)
 Fragile & can’t be bent in sharp angles

Glass Fiber
Optic Cable

LASER
Based on
the mode of
operation
Continuous
wave Laser
systems
High power
Q-switched
systems
Pulsed
Laser
systems
Based on
state of
active
medium
used
Tunable dye
Laser
Semiconductor
Laser
Solid state
Laser
Gas LaserBased on
the
mechanism
in which
Population
Inversion
is achieved
Three level
laser
Four level
laser

Fundamentals Of Laser
 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 colors
(or wavelengths) of light.
 Lasers emit light that is highly directional, that is,
laser light is emitted as a relatively narrow beam in a
specific direction.
 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.
 These three properties of laser light are what can
make it more hazardous than ordinary light. Laser
light can deposit a lot of energy within a small
area.

Common Component Of All
Laser
 Active Medium
The active medium may be solid crystals such as ruby or Nd:YAG,
liquid dyes, gases like CO2 or Helium/Neon, or semiconductors such
as GaAs. Active mediums contain atoms whose electrons may be
excited to a metastable energy level by an energy source.
 Excitation Mechanism
Excitation mechanisms pump energy into the active medium by one
or more of three basic methods; optical, electrical or chemical.
 High Reflectance Mirror
A mirror which reflects essentially 100% of the laser light.
 Partially Transmissive Mirror
A mirror which reflects less than 100% of the laser light and
transmits the remainder.

INCANDENT VS LASER
LIGHT
1. Many wavelengths
2. Multidirectional
3. Incoherent
1. Monochromatic
2. Directional
3. Coherent

GAS LASER
Gas lasers consist of a gas filled tube placed in the laser cavity.
A voltage (the external pump source) is applied to the tube to
excite the atoms in the gas to a population inversion. The light
emitted from this type of laser is normally continuous wave (CW).

HELIUM NEON GAS LASER

ND : YAG Laser
 Nd:YAG (neodymium-doped yttrium aluminium garnet;
Nd:Y3Al5O12) is a crystal that is used as a lasing medium for
solid-state lasers. The dopant, triply ionized neodymium, Nd(III),
typically replaces a small fraction (1%) of the yttrium ions in the
host crystal structure of the yttrium aluminium garnet (YAG), since
the two ions are of similar size.It is the neodymium ion which
provides the lasing activity in the crystal, in the same fashion as
red chromium ion in ruby lasers
YAG Rod

Nd:YAG lasers are optically pumped
using a flashtube or laser diodes. These
are one of the most common types of laser,
and are used for many different
applications. Nd:YAG lasers typically emit
light with a wavelength of 1064 nm, in the
infrared. However, there are also
transitions near 940, 1120, 1320, and
1440 nm.
Nd:YAG lasers operate in both pulsed and continuous
mode. Pulsed Nd:YAG lasers are typically operated in the
so-called Q-switching mode: An optical switch is inserted in
the laser cavity waiting for a maximum population inversion
in the neodymium ions before it opens. Then the light wave
can run through the cavity, depopulating the excited laser
medium at maximum population inversion. In this Q-
switched mode, output powers of 250 megawatts and pulse
durations of 10 to 25 nanoseconds have been
achieved.The high-intensity pulses may be efficiently
frequency doubled to generate laser light at 532 nm, or
higher harmonics at 355, 266 and 213 nm.

Application of LASER
 Many scientific, military, medical and
commercial laser applications have been
developed since the invention of the laser in
1958.
 The coherency, high monochromaticity, and
ability to reach extremely high powers are
all properties which allow for these
specialized applications.

COMPUTING SPEED
 At present the computing speed ranges from
256 kilobits per second to 1 gigabit per
second, which is slow for the present world.
 The ability to achieve a speed of 25 gigabits
per second can be done with the use of laser
chips.
 Lasers are already used to transmit high
volumes of computer data over longer
distances for example, between offices, cities
and across oceans using fibre-optic cables. In
computer chips, datamoves at great speed
over the wires inside, then slows when it is

MILITARY DEFENCE

METEOROIDS ATTACK
 The concept which was
used for military defense
can be used to destroy the
meteoroids coming towards
earth.
 These incoming meteoroids
can be shattered into
pieces, thus saving our
earth from any major
destruction.
 A group of strong laser
beams are focused
together to the target and
the target is shattered off.

MEDICAL FIELD
 Cosmetic surgery (removing tattoos, scars,
stretch marks, sunspots, wrinkles, birthmarks,
and hairs).
 Now a days EYE surgery can also be done
with help of laser.
 "No-Touch" removal of tumors, especially of
the brain and spinal cord.

CURIOSITY USING IT’S LASER
DEVICE IN ITS MISSION

INDUSTRIAL AND
COMMERCIAL

OTHER APPLICIATIONS
 Cutting and peening of metals and other material,
welding, marking, etc.
 Laserdrilling, Guidance
systems ,Rangefinder/ surveying, LIDAR/
pollution monitoring.
 To store and retrieve data in optical discs.
 In laser printers: gas and diode lasers play a key
role in manufacturing high resolution printing

 Diode lasers are used as a light switch in
industry, with a laser beam and a receiver
which will switch on or off when the beam is
interrupted, and because a laser can keep
the light intensity over larger distances than
a normal light, and is more precise than a
normal light it can be used for product
detection in automated production.

Laser Beam Injuries
 High Beam laser can cause skin burns.
 LASERs can cause serve eye injuries which
can cause permanent vision loss.

ApproximatePowerLimitforvisible
wavelengthonly
Class 4
Unsafe for eyes
Unsafe for skin
0.5W
Class 3B Unsafe for eyes
Generally safe for skin
5mW
Class 3R Safe with (0.25 s.) aversion
response no viewing aids
0.5W
Class 2M
Visible wavelengths only
Safe with no viewing aids
1mW
Class 2
Visible wavelengths only
Safe with (0.25 s.) aversion
response including viewing
aids
0.5W
Class 1M Safe with no viewing aids
220μW to 0.4μW
Class 1
No precautions
required
Laser Classification Table

GENERAL LASER LAB SAFETY
 Clothing: Long sleeve clothing should be
worn to protect skin. Wear enclosed footwear
in labs.
 Jewelry: watches & rings which could reflect
beams should not be worn.
 Viewing Aids: Never use microscopes,
telescopes, magnifying glasses etc to view
laser beams

GENERAL LASER LAB SAFETY
 Never directly view a laser beam.
 Never point a laser pointer at a person.
 Never over-ride interlocks
 Never remove covers from equipment
without approval from supervisors – laser,
high voltages and other hazards are
present.

THANK YOU