الفهرس 
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Abstract
Introduction
Laser is a device that generates or amplifies visible light waves. In fact, the word laser
is derived from the principle of the device itself: Ught Amplification by Stimulated Emission
of Radiation. The laser can generate a beam of light that is coherent, highly
directional, and highly intense. These properties have been used for a variety of remarkable
applications in medicine as well as many other spheres of our lives m.
Lasers have been used in dermatology for over twenty years. In the early years, clinicians
had only a few laser systems available to them <21. However, recently, there has been
a great increase in the understanding of laser-tissue interaction which has resulted in the
development of numerous new-generation laser systems that take full advantage of the unique
properties of laser light to achieve very specific and confined effects in tissue while
minimizing collateral damage !31.
The introduction of pulsed tunable dye lasers has considerably improved the treatment of
vascular lesions, particularly port-wine stain malformations in children. Other laser
systems available for treatment of vascular lesions include a wide range of the continuous-
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Introduction
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wave and quasi-continuous-wave lasers. Their use in conjunction with automated delivery
systems has improved results whilst reducing adverse effects. Increasing interest
in treatment of pigmented lesions and tattoos has led to investigation of a range of high
power short-pulse lasers, and results are promising. However, further work is needed in
all areas to determine which lesions respond best to each laser system, and which treatment
techniques are optimal a>.
The properties of the laser have been used for a variety of remarkable applications.
Because of its coherence, the beam can be adjusted to an accuracy that is within one third of an
inch per mile. Precise measurements of distance are then obtained by reflecting the laser beam
from a distant point and determining the time required for the light to make the round
trip. This method was used by sdentists to measure the distance between the earth and the
moon, with the help of a reflecting device placed on the moon by Apollo astronauts u>.
Lasers have been used to obtain extremely accurate alignment for such engineering projects
as pipelines. ln military use, a laser guided bombing system has proved highly accurate;
the target is illuminated by the laser beam and the bomb is then guided by the beam’s
reflection from the target m.
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Jntrocluc:tion
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In manufacturing industries, the laser can perform special tasks with speed and accuracy.
Cutting and drilling of ultra hard metals, such as tungsten, can be done much more easily and
quickly with a laser than with standard tools. Certain welding operations are ideal for
lasers, since the quick flash of heat binds materials together instantly and firmly m.
Another important use of the laser’s unique qualities is in ”holography”, a method
of producing three-dimensional images m. Specially focused laser beams can be used to
produce heat many times greater than that of the sun. The heat is capable of burning a hole
in a diamond in less than one second. In the field of medicine, a laser serves as a
surgical knife for delicate operations on the eye, brain, and other organs where conventional
operating methods are often difficult <4l.
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