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General Laser F A Q
This page contains some of the most frequently asked general questions about lasers that we have received. If you have a question that you feel should be included in this FAQ, please E-mail us.
Q: What does the word laser stand for?
A: The word laser is an acronym (word made from the first letters of other words). Laser
stands for Light Amplification by Stimulated Emission of
Radiation.
Q: Is the radiation from lasers harmful?
A: The radiation from lasers is light, a form of electro magnetic radiation, which is non-ionizing
radiation and is around us all the time. It can be dangerous under certain circumstances such as
when a laser beam is projected into the eye, onto the skin or onto flammable materials (see
Basic Laser
Safety). Ionizing radiation such as that from X-rays, Microwaves, and nuclear
materials is dangerous as it can cause cell damage and cancer. If treated with caution and
respect, a laser is not dangerous.
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Q: What is the star/sun shaped symbol I see all over the web site?
A: The symbol is a stylized or simplified version of the international “sunburst” symbol which stands for lasers.
The standard international symbol is shown on the left in the International "Lasers In Use" warning sign which
should be posted in areas where unshielded lasers are in use. You may even find a similar sign or logo inside your
CD player or CD-ROM drive as they use low power laser diodes to read the data from the disk. |
Q: Who invented the laser?
A: The actual inventor of the laser is lost in a storm of controversy, claims and counter claims.
Most historians will agree that the first recorded operation of a laser was on 7th July 1960 by
Dr. Theodore Maiman at the Hughes Research Labs in Malibu California. Dr. Maiman’s laser
was based on the theoretical ideas of Albert Einstein, Dr. Charles Townes and Arthur
Shawlow.
(See A
Brief History of Laser Light Shows.)
Q: Can lasers hurt me?
A: Yes. Lasers can hurt the part of the body that is most sensitive to light, the eye and laser
beams can also cause skin and clothing burns. This is why high power laser beams at shows are
usually well above your head (see Basic Laser
Safety).
Q: How can lasers hurt me?
A: If a high power laser beam strikes you in the eye it can cause a burn on your retina.
Just as you can use a magnifying glass to focus the sun and burn with the light, the lens in the human eye
focuses the laser beam down to a very small point on the retina which can cause a burn.
The focusing effect can concentrate a laser beam up to 100,000 times thus a one watt beam entering
the eye can be focused to a point with 100,000 watts of power, more than enough to cause a
severe retinal burn and loss of vision (see Eye and Skin Hazards in Basic Laser Safety).
Q: Are lasers powerful enough to use as weapons like we see in the Star Wars movies
and on Star Trek?
A: Fortunately present day laser systems are unsuitable for use as weapons as the power
needed to cut through space ships or do serious damage to metal objects is extremely high.
Presently lasers that are powerful enough to machine metal are large and heavy and require lots
of power and cooling water to operate thus are not useful as portable “death rays”.
Q: How is laser power measured?
A: Laser power is measured in watts - the same watts used to measure the power of light bulbs.
A 10 watt laser will appear much brighter than a 10 watt light bulb since the light from the bulb
travels in all directions and spreads rapidly, while the light from the laser is concentrated in a
beam only a few millimeters in diameter.
Q: What is the most powerful laser in the world?
A: How powerful is a matter of definition.
The Nova facility in the USA, now call the NIF (National Ignition Facility) is certainly the most powerful, albeit for rather short pulses.
Average power versus peak power, the military has HF and DF lasers in the megawatt range,
with continuous outputs. The brightest visible laser we have heard of was also a military product,
about 500 Watts of red, we are not sure of the lasing medium.
Q: Can I build my own laser?
A: To build your own laser, you would have to have access to a precision machine shop to
build the frame, have glassblowing skills to make the tube, vacuum equipment to pump down the
tube and access to rare gasses to fill the tube; you would also need considerable electronics
skills to build the exciter (power supply). It would be like trying to build your own light bulb or
fluorescent tube. It is simpler to purchase a laser as low cost HeNe and diode lasers are readily
available.
Q: I still want to try building a laser... is there any place I can get plans?
A: You can visit the Laser
Hobbyists topic in our Backstage Area which has a Laser
Construction page with some information that may be helpful. Be leery of those who offer low cost plans for building a laser on the net as
these plans are often useless.
Q: I need more technical information about lasers. Where can I look?
A: The Backstage area of LaserFX.com contains a lot of technical information about laser light
show applications. For more technical information about the lasers themselves, Sam Goldwasser
maintains Sam's Laser FAQ which is filled with technical details on a variety of lasers -
LaserFX.com is pleased to act as a gateway for Sam's
Laser FAQ.
Q: Do all Lasers need to have a cooling system?
A: Small lasers such as HeNe and diode lasers usually do not need any special cooling systems
as they cool by convection of the air around them, or by conduction of the heat into the
mounting or casing. As the output power of the laser increases, the amount of heat produced
increases and cooling systems have to be used. CW lasers up to about one watt can be
air-cooled, over 1 watt most lasers require water cooling as air can not remove the heat fast
enough, although there are Copper Vapor and YAG lasers that produce several watts of optical
power and are air-cooled.
Q: I have the "Laser FX" unit which projects multiple colour images in response to a
music system. Unfortunately the bulb is missing or burned out. I have the packet the
bulb came in - on the front of the packet it reads: "Laser FX lS-01" and on the back it
reads "Laser FX 173 M32 lgt" I have searched everywhere and cannot find such a
bulb, do you know where I can get one?
A: Laser F/X International (that's us) are
not the manufacturers of this unit - the California based company that made it went broke some years ago. We get a couple of requests a month
for this info but we do not know what type of bulb was originally used. Our only advice is to
contact a major vendor of bulbs like GE or Sylvania and see if you can find a replacement.
(NOTE: If anyone finds a suitable replacement bulb, please write us and let us know the
make/model/type of the bulb so we can add this info to the FAQ.)
Update: G. Jones [Hendersonville, NC] writes "I used a GE type T, Halogen 10 watt, 12 volt bulb available at Wal-Mart. It works, but is a little dim. I plan on trying a 20 watt bulb later. Feel free to let people know this worked for me."
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