The Light of Lasers

Lasers are such curious beasts, yet what they can produce is rather stunning. I've liked lasers for a long time and have wanted one for some time. Now I've got one :-) It's only a toy (compared to industrial lasers!) but it is still a laser.

So what is a laser? Laser is actually an acronym for Light Amplification by Stimulated Emission of Radiation. Which means what? Well I'll try and explain :-) A laser works by "exciting" electrons, usually using electricity, to such an extent that they are "creating" light. All lasers tend to follow the same principles, but there are several sorts and several different technologies and gasses that can be used to create all sorts of wonderful light.

In the UK, lasers have five classifications: Class I through to Class IV. Okay, so that's four...but there are two types of class III laser - classes IIIa and IIIb. Class I lasers you tend to find in CD players. Class IV lasers can burn you rather nastily. Class IIIa is considered to be the "safest" class before you can cause yourself physical damage...however, that said:

WARNING!

Any laser, no matter how large or small, can blind you permanently. Never ever stare into a laser beam without knowing the risks. It is not my fault if you end up with serious eye problems if this page has caused you to fiddle with lasers and end up blinding yourself!

If you do end up buying a laser, be it a full blown thing, or a diddly little laser pointer, here's a few hints for safety:

Don't point it in someones eyes - you'll end up blinding them.
Careful when using mirrors and glass. A laser beam can reflect of these and may accidently hit someone in the eyes. Controlling where a laser is pointing using a mirror is risky, even at the best of times.
Careful of jewels - whilst they can produce some rather nice scatter, they could also end up directing a beam into someones eyes.

Laser Colours

In gas-style lasers (ie, lasers that use a laser tube holding some sort of gas) the colour produced depends on the gas and optics used. Some popular choices are:

Argon - produces a cyan light from which blue and green can be obtained using a prism.
Helium-Neon - produces a low power red beam.
Krypton - often called 'white light' lasers as the light produced is pinkish white. Again a prism or filters can be used to seperate the colours, of which there can be many.

Photos

These photos are rather experimental, so don't expect much!! The camera and laser were pointed in typical student fashion, using folders, books, 2p peices etc... to angle and direct both. The trick with laser pointers is to find something to hold the button down so you can leave the laser too emit light without being near it. Bluetak and sellotape are perfect for this :-)

This is my laser toy :-) Class IIIa, 670nm (red beam) at 5mW

[Picture 1 of scatter]

This is the first photo, so it's highly experimental. The laser was pointing
roughly in a 45 degree angle towards a jewel where the scatter was produced.
Maybe a tripod could be in order instead of using folders to support the
camera :-) It looked better actually seeing it! But this is promising...

[Picture 2 of scatter]

This is the second...although it looks a bit of a mess...and I think the
scan may actually be a bit dubious (I'll handle the photos with more care
next time :-) The laser was angled on the same (horizontal) axis as the
jewel this time. The scatter was produced on the wall.

[Picture 1 of prism demo]

I had a tripod by the time I took this piccy - there are two prisms here,
one equalateral, the other a right-angled one. They were placed on the
desk, which is in a corner of my room (hence the three solid "blobs" you
can see).

[Picture 2 of prism demo]

Again both prisms...this time I put them on the floor to take an overhead
shot. The prims were placed on a few bits of A4 paper (to get a white
background, else you wouldn't be able to see the beam).

Laser Resources

There are some rather good images of laser's at these sites, or from links of these sites. They also have more indepth information about lasers than what I have here... :-)

International Laser Display Association
Laser FX
Laser Star Astropysics
Laser Network
Laser Fantasy International

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