This document discusses lasers and laser beams. It begins by defining a laser beam and explaining how lasers work using stimulated emission. It then discusses properties of laser beams like coherence, focusability, and the ability to travel in a straight direction. The document also covers laser safety hazards and controls. It summarizes the effects of laser energy on eyes and discusses using engineering and administrative controls as well as personal protective equipment to mitigate hazards. The conclusion discusses potential applications of laser communication in space.

1. Done by:
P.Dhanush,
1670228,
A3.

2. Introduction
 Laser beam is defined as light beams propagating
dominantly in one direction.
 A laser is a device that generates light by a process
called STIMULATED EMISSION
 The name LASER is an acronym for Light
Amplification by the Stimulated Emission of
Radiation.
 In 1917, Albert einstein first theorized about the
process which makes lasers possible called
"Stimulated Emission."
 Laser beams often have a small optical bandwidth.

3.  Some lasers emit continuously, but a laser beam can
also consist of a fast sequence of pulses, with many
millions or even billions of pulses per second.
 A laser beam of visible light with sufficiently high
power may be visible when propagating in air, a much
brighter spot is seen on that screen, since most of the
optical power is scattered at this point.
 Laser beams exhibit good focusability and the
potential.
 It is a powerful light in a straight direction and could
be reflected from certain items like glass.

4. When a single beam laser cuts with
acceptable speed it generates too much heat
damage on the wafer.
To improve the quality of the cut, less laser
power has to be applied.
This reduces the cutting speed too much.
Multiple beam cutting limits the local heat
load sufficiently while achieving a high
material removal rate.
Thus combining a high dicing quality with high
speed ..

5. Near Field and Far Field of
Laser Beams
 The near field of a laser beam is understood to
be the region around the beam waist.
 beam waist, i.e., in a distance from the focus
which is large compared with the effective
Rayleigh length

7. Laser hazards
 Acute exposure of the eye to lasers of certain
wave lengths and power can cause corneal or
retinal burns. Chronic exposure to excessive
levels may cause corneal or leniticular
opacities or retinal injuries.
 Acute exposure to high levels of optical
radiation may cause skin burns.
 Some lasers require hazardous or toxic
subsstances to operate
 Most kasers utilize high voltages that can be
lethal.

8. Laser and eyes
 What are the effect of laser energy on eye?
1) Laser light in visible to near infrared
spectrum which can cause damage to the
retina resulting in Scotoma.
2) Laser light in the ultravoilent or fae
infrared spectrum can cause damage to the
camera and to
the lens.
 Visual disorientation due to retinal damage
may not be apparent to the operator until
considerable thermal damage has occurred.

9. Control measures
ENGINEERING CONTROLS
 interlocks
 Enclosed beam
ADMINISTRATIVE CONTROLS
 Standard operating procedures(SOPs)
 Training
PERSONNEL PROTECTIVE
EQUIPMENT(PPE)
 Eye protection

10. Laser fundamentals
 The light emitted from a laser is
monochromatic, that is it is of one color/wave
length.
 Laser emit light that is highly directional, that is
, laser light is emmited as a relatively narrow
beam in a specific direction. Ordinary bulb
 The light from a laser is said to be coherent.
These properties of laser makes them
hazardous than ordinary light.

11. Conclusion.
 Laser communication in space has long been a
goal for NASA because it would enable data
transmission rates that are 10 to 1000 times
higher than traditional radio waves.While lasers
and radio transmission both teavel at light
speed, laser can pack more data. It’s similar to
moving from a dial-up internet connection to
broadband. Astronomers could use lasers like
very accurate rulers to measure the movement
of planets with unpreceeding precision.

12.  Website references:
1) www.slideshare.net/donpraju/laser-ppt
2)www.alsiinternational.com/technology/
multibeam_process/multi_laser_beam_te
chnology