Game Development Reference
In-Depth Information
The light generated by a laser is very different from normal light. For one thing, laser light
is monochromatic (one color) because the photons are emitted by atoms at the same energy
state and therefore have the same wavelength. Rather than the chaotic light produced by a
flashlight, laser light is coherent, meaning that the photons travel together in a narrow beam.
Laser light is very directional and dissipates slowly. A laser beam can illuminate an object many
miles away. Another characteristic of lasers is that many of them generate other forms of radiation
than visible light, including
microwave
and
infrared
radiation.
Types of Lasers
A laser requires a lasing medium in which atoms can be excited to a higher energy state. Many
different substances meet this requirement, and there are therefore lots of different types of
lasers. As discussed, the lasing medium can be gaseous, liquid, or solid. In this section, we will
see some general types of lasers and discuss some of the applications for each one.
Lasers are also characterized by the wavelength of the radiation that they emit. Some lasers
will generate visible light and others will generate invisible forms of radiation such as microwave
or infrared radiation. The range of possible laser wavelengths is part of what is known as the
electromagnetic spectrum
that divides all of the possible wavelengths into different regions.
Table 14-1 displays the wavelength for the types of radiation that lasers can emit.
Table 14-1.
Laser Radiation Wavelengths
Radiation Type
Wavelength (
nm
)
Ultraviolet
1 - 400
Visible light
400 - 700
Infrared
700 - 1.0
e
+ 5
Microwave
1.0
e
+ 5 - 1.0
e
+ 8
Gas Lasers
Gas lasers use a tube filled with gas as the lasing medium. Typical gases used in gas lasers are
helium, helium and neon, and carbon dioxide (CO
2
). CO
2
lasers emit light in the infrared and
microwave part of the electromagnetic spectrum. Infrared radiation is essentially heat, and
powerful CO
2
lasers can melt through steel. Another type of gas laser known as an
excimer
laser
uses a mixture of a volatile gas such as chlorine or fluorine with an inert gas such as argon,
krypton, or xenon. Table 14-2 shows the wavelength and type of radiation emitted by various
types of gas lasers.
1, 2
