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Visualization
- Visualize The Future
- Wide Angle
- Hollywood
- A Mixed View
- Electromagnetic
- Vision
- Color
- X-Ray
- Lasers
- Optics in Everyday Life
- Optics in Science
- Light Microscopes
- Electron Microscopes
- Medical Imaging
- Eye Glasses
- Surveillance
- Telescopes
- Optics in Review
- TV
- Scientific Visualization
- Virtual Reality
- What's Next ?
Other Pages
Visualizing The Future
Lasers
Dr. Charles H. Townes (PhD in Physics, California Institute
of Technology) started working for Bell Telephone Labs, designing
radar bombing systems during WWII. He turned his attention
to applying the microwave technique of wartime radar research
to spectroscopy, a powerful new tool for the study of the
structure of atoms and molecules and as a potential new basis
for controlling electromagnetic waves.
More research followed in microwave physics, particularly
studying the interactions between microwaves, molecules, and
atoms. In the early 50s he invented the "maser," a device
and an acronym for "microwave amplification by stimulated
emission of radiation." A few years later with his brother-in-law,
Dr. A.L. Schavlow (Stanford), he showed theoretically that
masers could operate in the optical and infrared regions.
The laser was born. Laser stands for "light amplification
by stimulated emission of radiation.
Ordinary natural and artificial light is released by energy
changes on the atomic and molecular level that occur without
any outside intervention. A second type of light exists, however,
and occurs when an atom or molecule retains its excess energy
until stimulated to emit the energy in the form of light.
Lasers are designed to produce and amplify this stimulated
form of light into intense and focused beams. The special
nature of laser light has made laser technology a vital tool
in nearly every aspect of everyday life including communications,
entertainment, manufacturing, and medicine. Laser surgery
used for correcting vision problems has become routine, if
not big business.
The lasers commonly employed in optical microscopy are high-intensity
monochromatic light sources, which are useful as tools for
a variety of techniques including optical trapping, lifetime
imaging studies, photobleaching recovery, and total internal
reflection fluorescence. In addition, lasers are also the
most common light source for scanning confocal fluorescence
microscopy, and have been utilized, although less frequently,
in conventional widefield fluorescence investigations.
In a few decades since the 1960s, the laser has gone from
being a science fiction fantasy, to a laboratory research
curiosity, to an expensive but valuable tool in esoteric scientific
applications, to its current role as an integral part of everyday
tasks as mundane as reading grocery prices or measuring a
room for wallpaper.
Any substantial list of the major technological achievements
of the twentieth century would include the laser near the
top. The pervasiveness of the laser in all areas of current
life can be best appreciated by the range of applications
that utilize laser technology.
At the spectacular end of this range are military applications,
which include using lasers as weapons to possibly defend against
missile attack, and at the other end are daily activities
such as playing music on compact disks and printing or copying
paper documents.
Somewhere in between are numerous scientific and industrial
applications, including microscopy, astronomy, spectroscopy,
surgery, integrated circuit fabrication, surveying, and communications.
The two major concerns in safe laser operation are exposure
to the beam and the electrical hazards associated with high
voltages within the laser and its power supply. While there
are no known cases of a laser beam contributing to a person's
death, there have been several instances of deaths attributable
to contact with high voltage laser-related components.
Beams of sufficiently high power can burn the skin, or in
some cases create a hazard by burning or damaging other materials,
but the primary concern with regard to the laser beam is potential
damage to the eyes, which are the part of the body most sensitive
to light.
A pre-recorded compact disk is read by tracking a finely focused
laser across the spiral pattern of lands and pits stamped
into the disk by a master diskette. The laser beam is focused
onto the surface of a spinning compact disk, and variations
between the height of pits and lands determine whether the
light is scattered by the disk surface or reflected back into
a detector.
There are many other kinds of lasers, like ion lasers, argon-ion
lasers, diode lasers, helium-neon lasers, Ti:Sapphire Mode-Locked
Lasers, and Nd:YLF Mode-Locked Pulsed Lasers (neodymium: yttrium
lithium fluoride).
In 2005, two Americans and a German won the Nobel Prize in
Physics for Laser Research. Roy J. Glauber of Harvard University
was honored for work applying quantum theory to light emitted
by lasers. His work allegedly will help explain a major scientific
paradox: the dual nature of light behaving like both a particle
and a wave.
John L. Hall, JILA Institute, University of Colorado (Boulder),
and Theodore W. Hansch, Ludwig-Maximilians University in Munich
will share the Prize for their development of techniques to
precisely control the frequency of lasers, allowing measurement
of physical properties not only of atoms, but of space and
time, with unprecedented accuracy.
Before the laser, researchers used classical 19th century
optics theory to explain the behavior of light. Many researchers
believed that quantum theory, which had proved successful
in describing the behavior of matter, could not be applied
to light.
The development of lasers operating at single frequencies
made advances in the study of atoms and molecules possible.
But those studies were limited by the inability to lock a
laser onto a specific frequency. The goal was to stabilize
a laser so its frequency doesn't change, thereby allowing
a practical way to measure the frequency of light.
Such accurate measurement will increase the accuracy of atomic
clocks from the current 10 digit to 15 digit accuracy. This
kind of precision will not only enhance the accuracy of clocks
but also the global positioning system, improve the navigation
of long spaceflights, and help in the pointing of space telescopes.
Holography
Holography was invented in 1948 by Hungarian physicist Dennis
Gabor. He received the Nobel Prize in physics in 1971. The
discovery was a result of research involving electron microscopes,
but it was the laser that ultimately made holography possible.
Holography is the science of producing 3-dimensional images
called holograms. Holography is also used to optically store
and retrieve information. Holograms gained popularity in such
movies as Star Wars, Star Trek and AI: Artificial Intelligence.
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