Game Development Reference
In-Depth Information
Pulsed and Continuous Wave Lasers
Another fundamental distinction between lasers is whether the beam they produce is contin-
uous or is generated as a series of short pulses. A pulse laser generates a beam for very short
periods of time, usually tiny fractions of a second. The peak power, energy divided by pulse
duration, generated by pulse lasers can be very high, but the average power, energy delivered
per second, is usually quite low because the pulse times are small. Pulse lasers are used for
such applications as nuclear or plasma (high-temperature gas) research.
Continuous wave or CW lasers generate a steady beam of light or other radiation for periods
of time that generally exceed one second. A laser pointer is a typical example of a low-power
CW laser. CW lasers generally have lower peak power than pulse lasers but have a relatively
high average power. There is a wide range of uses for CW lasers from surgical operations to
home electronics to research facilities. Military lasers, those used to shoot down missiles and
airplanes or intended to strike ground targets, are typically CW lasers.
Military Lasers
Unless you are creating a “research laboratory” simulation, most of the time when you include
lasers in your game simulations they will be used in combat situations. Lasers used in combat,
generally classified as
military lasers
or
high-energy lasers
(HEL), aren't in the realm of science
fiction. There have been military research programs for decades in many different countries to
develop viable military lasers that will shoot down airplanes or missiles, disable sensors and
electronic devices, burn through metal, and blind or kill people.
Military lasers are generally CW lasers. The damage done by a laser is proportional to the
energy delivered to the target, and CW lasers generate a higher average power level than do
pulse lasers. Existing or proposed military lasers are also very large and are generally housed
inside an orbiting satellite, on board an aircraft or ship, or inside a ground facility. Currently,
no high-energy lasers exist that are small enough or light enough to be carried by a person,
partly because of the enormous power requirements of these weapons. Another big issue with
powerful military lasers is that they generate an enormous amount of heat when they operate,
and this heat must be dissipated somehow to allow continued operation of the laser.
There are a large number of previous or existing military laser programs. In the next
subsections, we'll discuss details of three military laser research programs to give you a flavor
of the military laser systems that are in the planning phase today. None of these systems have
been successfully built, although all three of them have undergone development testing, and
full or half-scale prototypes for the first two are anticipated within a few years.
ABL
The Airborne Laser, or ABL, is designed to be carried aboard an aircraft such as a Boeing 747.
Its mission is to destroy intercontinental ballistic missiles (ICBMs) during the ascent portion of
their flight.
3
The ABL uses a chemical oxygen-iodine (COIL) gas laser for the destructive laser
beam and several smaller lasers for targeting and acquisition. The ABL system takes up most of
the interior space inside the 747 aircraft. The laser beam is sent through a pipe to the forward
part of the airplane where it is aimed towards its target using very fast, lightweight steering
mirrors.
