Invisible nous apporta ses lumieres en ce 2007/11/08 08:08:
> M_a_r_c wrote:
> 
>>> (I still can't figure out why you can use an oscilator to make radio 
>>> waves, but not light rays...)
>>
>> Is not a laser an excitated resonant optical cavity eg a oscillator?
> 
> Actually, I thought it was a tube full of extremely hot gas with some 
> mirrors at the ends? (I don't know a huge amount about lasers.)
There are laser diodes, no gas at all and barely any heat. How about crystal 
lasers, the ruby ones been the archetype of all lasers: the famous RED laser 
beam! Gas lasers use cool, and idealy COLD low presure gas, and may NOT have ANY 
mirror at all, and often only one if they have any.
Usualy, heat is the enemy of lasers: they need to stay cool to stay 
monochromatic and keep a parallel beam.
You can build a nitrogen UV laser in your kitchen! You need a large 2 faces 
project board, some coper fold, some palstic, a screw, a bunch of capacitors and 
diodes, an ossilator, a nitrogen source, a cheap water jet vacuum pump, a 
welding iron and welding strip. ANYBODY can gather all components.
I have the plans if you want. They where published in the Scientific America 
magazine, with all needed instructions, as well as the working principles.

-- 
Alain
-------------------------------------------------
You know you've been raytracing too long when you've ever "lost" a Julia fractal 
because you're not quite sure how to align things in four dimensions.
Dylan Beattie

Post a reply to this message