·
Gas Lasers:
Gas lasers using many gases have been built and used for many
purposes. Examples of gas lasers include:
The
helium–neon laser (HeNe) emits at a variety of wavelengths and units operating
at 633 nm are very common in education because of its low cost.
Carbon
dioxide lasers can emit hundreds of kilowatts at 9.6 µm and 10.6 µm, and are
often used in industry for cutting and welding.
· Chemical Lasers:
These are lasers which are produced by chemical reactions.
Chemical compounds store large amount of energy. These may be released by
exothermal chemical reactions. These kinds of reactions follow release of
energy and this energy is made use to produce laser radiation.
·
Excimer Lasers:
Excimer lasers are powered by a chemical reaction involving an
excited dimer, or excimer, which is a short-lived dimeric or heterodimeric
molecule formed from two species (atoms), at least one of which is in an
excited electronic state. They typically produce ultraviolet light, and are
used in semiconductor photolithography and in LASIK eye surgery.
·
Solid-state Lasers:
Solid state laser materials are commonly made by doping a
crystalline solid host with ions that provide the required energy states. For
example, the first working laser was a ruby laser, made from ruby
(chromium-doped corundum). Formally, the class of solid-state lasers includes
also fiber laser, as the active medium (fiber) is in the solid state.
Practically, in the scientific literature, solid-state laser usually means a
laser with bulk active medium; while wave-guide lasers are caller fiber lasers.
·
Fiber-hosted Lasers:
Solid-state lasers where the light is guided due to the total
internal reflection in an optical fiber are called fiber lasers. Guiding of
light allows extremely long gain regions providing good cooling conditions,
fibers have high surface area to volume ratio which allows efficient cooling.
In addition, the fiber's wave guiding properties tend to reduce thermal
distortion of the beam Erbium and ytterbium ions are common active species in
such lasers.
·
Semiconductor Lasers:
Commercial laser diodes emit at wavelengths from 375 nm to 1800
nm, and wavelengths of over 3 um have been demonstrated. Low power laser diodes
are used in laser printers and CD/DVD players. More powerful laser diodes are
frequently used to optically pump other lasers with high efficiency. The
highest power industrial laser diodes, with power up to 10 kW (70dBm), are used
in industry for cutting and welding. External-cavity semiconductor lasers have
a semiconductor active medium in a larger cavity. These devices can generate
high power outputs with good beam
quality, wavelength-tunable narrow-linewidth radiation, or ultra-short laser
pulses.
·
Dye Lasers:
Dye lasers use an organic dye as the gain medium. The wide gain
spectrum of available dyes allows these lasers to be highly tunable, or to produce
very short-duration pulses (on the order of a few femtoseconds)
·
Free
Electron Lasers:
Free electron lasers, or FELs, generate coherent, high power radiation
that is widely tunable, currently ranging in wavelength from microwaves,
through terahertz radiation and infrared, to the visible spectrum, to soft
X-rays. They have the widest frequency range of any laser type. While FEL beams
share the same optical traits as other lasers, such as coherent radiation, FEL
operation is quite different. Unlike gas, liquid, or solid-state lasers, which
rely on bound atomic or molecular states, FELs use a relativistic electron beam
as the lasing medium, hence the term free electron.
·
Exotic
Laser Media:
In September 2007, the BBC News reported that there was
speculation about the possibility of using positronium annihilation to drive a
very powerful gamma ray laser. Dr. David Cassidy of the University of
California, proposed that a single such laser could be used to ignite a nuclear
fusion reaction, replacing the hundreds of lasers used in typical Inertial
confinement fusion experiments.
I am working for the website and giving out my best of efforts to provide the viewers of the website a richest source of accurate information to guide in the difficulties of life face by a common people to learn some thing.the author is enthusiastic about its viewers that they get the information for what they visited this webpage
ConversionConversion EmoticonEmoticon