Lasers emit a focused, intense beam of coherent light through stimulated emission of radiation. The first laser was created in 1960 by Theodore Maiman using a ruby crystal. Lasers have common components including an active medium to emit light, an excitation mechanism to energize atoms, and mirrors to reflect the beam through the medium. Laser light is useful for applications like barcodes, surgery, manufacturing, and communications due to its monochromatic, coherent, and collimated properties.

1. LASERS
By: Lucía Vicario and Tania Martín

2. WHAT IS IT?
• A laser is a device that emits light
through a process of optical amplification
based on the stimulated emission of
electromagnetic radiation.
• A laser is a coherent and focused beam of
photons
• Lasers are a special form of light. Laser
light does not exist in nature. Only
human technology can create laser light.
• The acronym laser stands for "light
amplification by stimulated emission of
radiation.“

3. HISTORY OF LASER
• In 1916, Albert Einstein established
the basic fundaments to built a laser
and a maser( microwaves).
• The first laser was designed by
Theodore Maiman and was made of
ruby.
• It worked for the first time in 1960.
• Townes and Arthur Leonard
Schawlow are also considered the
inventors of the laser, which was
patened that same year.

4. DESIGN OF A LASER
COMMON COMPONENTS:
Active Medium: it may be a solid crystal
such as ruby. It contains atoms which
can emit light by stimulated emission.
Excitation mechanism: It is a source of
energy to excite the atoms to the
proper energy state.
High Reflectance Mirror: It is a mirror
which reflects essentially 100% of the
laser light.
Partially Transmissive mirror: A mirror
which reflects less than 100% of the laser
light.
Optical Resonator: reflects the laser
beam through the active medium for
amplification.

5. What is "ordinary" or natural light?
• Ordinary light, like sunlight, is made up of many different
wavelengths, or colors, of light. If you put all the different
colors together, you get white light.
. . . and how is laser light different?
• First, the light from a laser contains exactly one color or
wavelength rather than a lot of different wavelengths. Second,
they are all "waving" together. Scientists say the laser light is
"coherent” and "monochromatic" , meaning of one color.
LASER FUNDAMENTALS

6. • While light waves from ordinary sources (such as flashlights,
lightbulbs, or the Sun) spread out in all directions . . .
• . . . laser light waves all travel in the same direction, exactly parallel
to one another. Scientists say the laser light is "collimated.“ Laser
light can deposit a lot of energy within a small area.

7. As the laser light is monochromatic, coherent, and
collimated, all of its energy is focused to produce a
small point of intense power. This focused power
makes laser light useful for cutting, welding and for
other uses…
• Bar code readers in stores use lasers.
• Medicine: Doctors use lasers to do delicate surgery,
such as eye surgery, bloodless surgery, surgical
treatment, kidney stone treatment, dentistry.
• Lasers carry TV and telephone signals over special
cables.
• Metal workers use lasers to cut and weld metal into
everything from street light poles to cars.
• Workers in clothing factories use lasers to cut
through hundreds of layers of fabric at once.
• CD and DVD players use lasers
• Cosmetic skin treatments: acne treatment, cellulite
and striae reduction, and hair removal.
USES

8. ARE THEY HARMFUL?
•Lasers can cause a car accident
beacuse the can distract
or blind the driver temporarily.
•If a person stares into a laser, even a
small one it could cause a spot on the
retina.
•At around 150 milliwatts, the beam
from a laser can be felt on the skin.
•At around 500 milliwatts the beam
starts to burn the skin if the person is
a few meters away.

9. HOW DOES LASERS WORK?
A laser is created when the
electrons in atoms in special
glasses, crystals, or gases
absorb energy from an
electrical current or another
laser and become “excited.”
The excited electrons move
from a lower-energy orbit to
a higher-energy orbit
around the atom’s nucleus.
When they return to their
normal or “ground” state,
the electrons emit photons
(particles of light).

10. HOW CAN WE MAKE A LASER?
• https://youtu.be/y3SBSbsdiYg

11. QUESTIONS
• Who invented the laser?
• Name two uses for lasers
• What was the first laser made of?