Ask Me Everything1

so special lasers?

A laser is a device that produces an intense beam of pure light. When the laser was first developed, it was called “an invention looking for a use,” because no one knew what to do with it. Today, the special qualities of their light mean that lasers have many applications—you probably use a laser every day without even knowing it.

Tell me morę:

how does a laser work?

A laser can be madę from a solid materiał, a liquid, or a gas—this is called the lasing medium. Energy, usually electricity or bright light, is pumped into the lasing medium, where atoms soak up this energy and release it again as light. The light bounces between two mirrors, gaining in strength as it does so. One of the mirrors lets some light through—this is the laser beam.

Flprtrir pirpnit wirp rarrip*?

Fully reflecting mirror bounces light _{current that} ,_{ights the fiash tube} back into the lasing medium

Partially reflecting mirror lets light beam out

Flash tube sends fiash of light into the lasing medium

Did you use a laser today?

You can find lasers in all types of places:

✓    CD players

✓    DVD players

✓    Telephone lines

✓    Cable television

✓    Laser printers

✓    Games consoles

^ ✓ Bar codę readers in Stores I ✓ Visual effects in stage shows I ✓ Scientific research I ✓ Hospitals I ✓ Industry

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_tengths, ^rand° JL_nt directions. and goin9’ⁿJ? g^ade of waves    .

from a laser is m    _{ail in ste}p

_are a« tbe same 1 9_dallg0ing

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WHAT’S IN A NAME?

The word laser is madę up from the first letters of Light Amplification by Stimulated Emission of Radiation, which is a scientisfs way of describing how a laser works.

Lasing medium is a ruby crystal

Can you tie a laser beam in a knot?

Light usually travels in straight lines, but a laser beam can be bent by shining it through a very thin strand of glass called an optical fiber. The light stays inside the glass fiber, even if the fiber is bent or tied in a knot. So the answer is yes!

L

W

|W|	Less than
S	0.001 watts
U	The power of a laser pointer (a pen-like device that
S	uses a laser to shine a spot of light on something)
c	Up to 0.01 watts
H	The power of the laser in a DVD player
3	0.25 watts
	The power of lasers in DVD burners
cr	30-100 watts
CD	The power of a surgical laser
	100-3000 watts
CA	The power of an industrial laser

(c) 2011 Dorling Kindersley. All Rights Reserved.