Garment idustry
The programmed cutter can cut dozens to hundreds of thicknesses of cloth, and
can cut out every piece of the garment in a single run.
The usefulness of the laser for such cutting operations comes from the fact that the beam is highly collimated and can be further focused to a microscopic dot of extremely high energy density for cutting.
Barcode Scanners
Supermarket scanners typically use helium-neon lasers to scan the universal
barcodes to identify products. Smiconductor laser are often used in these scanners
too.
Laser Fusion
Laser fusion attempts to force nuclear fusion in tiny pellets or microballoons
of a deuterium-tritium mixture by zapping them with such a high energy density
that they will fuse before they have time to move away from each other. This
is an example of inertial confinement.
Two experimental laser fusion devices have been developed at Lawrence Livermore
Laboratory, called Shiva and Nova. They deliver high power bursts of lase light
from multiple lasers onto a small deuterium-tritium target. These lasers are
neodynium glass lasers which are capable of extremely high power pulses.
Laser printing.
Semiconductor lasers are used in laser printers. The typical laser for this
application is the aluminum-gallium-arsenide (AlGaAs) laser at 760 nm wavelength,
just into the infrared.
DVD
A DVD player contains a laser that is used not because it produces a parallel
beam, but rather because the light emerges from a tiny point, which enables
it to be focused on the different layers of the disc. By moving the lens sideways
- laterally, it is possible to reach areas farther in or out on the disc. By
moving the lens along the beam - longitudinally, different depths can be reached
in the disc. The information, ones and zeros, is stored in several layers, and
only one layer is to be read at a time. Every point on a particular layer is
read during every revolution of the disc.
In order to make room for a lot of information on every disc, the beam has to
be focused on as small an area as possible. This cannot be done with any other
light source than a laser.
Today this area has been reduced to about half a square micrometer, which yields
2 megabits or 0,25 MB(yte) per mm2.
Laser Pointers
Laser pointers are made from inexpensive semiconductor lasers that together
with a lens produce a parallel beam of light that can be used to make a bright
spot to point with. Their range is very large. If one points at a surface 200
meters (220 yards) distant in the dark, a person standing close to the object
being pointed at will have no trouble seeing the shining spot (of course, someone
else has to hold the laser). On the other hand, the one holding the pointer
will have difficulty seeing the spot. The eternal question of range has more
to do with the light's behavior on its way back to the sender than with the
length of the beam.
Laser Sights
Laser sights for rifles and guns can be based on several different principles.
Some send a laser beam parallel to the trajectory so that the point of impact
becomes visible. This method exposes the marksman. Some project a red dot inside
a telescopic sight (instead of cross hairs). In both cases, the dot can be produced
with a ring around it.
Navigation
One important use is aircraft navigation. The main stabilizing device in a modern
airplane is a gyroscope, but this is expensive and bulky. Currently some work
to create semiconductor laser-driven gyro, about the size of a computer chip,
far smaller and lighter and requiring far less power than a conventional gyroscope
being done.
Medicine
Because of the differences in absorption properties for various wavelengths,
a number of different potential applications for semiconductor lasers exist.
These other types of laser-tissue interactions include photocoagulation, photothermal
ablation, and photochemical ablation. Other categories of potential medical
applications include: photodynamic therapy, thermotherapy, non-invasive surgery,
minimally-invasive surgery, invasive surgery, and diagnostics and imaging.
Speed Measurement Using Laser
The method the police use to measure car speed is based on a laser signal that
is sent towards the target. This beam bounces back and is mixed with light that
has not hit the car. The result is an oscillation - the same as when you tune
a guitar - with higher frequency (more treble) the faster the target moves.
The speed has to be measured straight from the front or from the back. If it
is measured at an angle, the speed is underrated. This means that you cannot
get false values that are too high.
The measurement is dependent on the car having something that reflects well.
The license plate is perfect, as are different types of reflecting objects.
Fogged surfaces are okay, but reduce the maximum distance.
Laser Distance Meter
The primary users of laser distance meters today are surveyors and constructors,
but the car industry is catching on. Least spectacular is the so-called parking
assistance that helps the driver to estimate the distance to the car behind
when parking. A more recent application measures the distance to the car in
front of the driver when driving on highways or other roads. You simply lock
in the distance to the car in front of you in order to maintain that distance.
This makes driving more efficient and faster as long as it all works. This kind
of laser is found in most robots with mechanical vision.
Optical Loudspeaker Cable
Any amplifier of worth nowadays has an optical cable for transmission to the
loudspeakers. The advantage of this method is that it is insensitive to interference
from electromagnetic fields, that is interference from electronic devices and
radio transmitters such as cell phones. The light source used as a transmitter
is a small laser semiconductor. All equipment using optic cable uses the same
standard. For example, the maximum bit rate for broadband applications is today
50-100 times higher using optics, but the potential ratio is 10,000 times.