Lasers (A possible new way to make one)

Alright I have a question. Yes I know this is probably really childish but, why do we spend so much money building huge lasers when we could just use 300 magnifying glasses and a beam of light?
I mean I'm sure most of you have used a magnifying glass to kill an ant. So why can't we use a lot more magnifying glasses, lined up in a row, to make an even powerful laser?

Quite simply, light when it passes through anything undergoes refraction, even if only by a tiny amount. This is because light passing from one medium to another is refracted.

Imagine also the idea that the more material the beam has to go through, it will end up losing photons as it goes. This means the strength of the beam will deteriorate as you make it pass through more lenses.

You had a good idea though.

Light going through a magnifying glass doesn't go into a line as it passes through. Say the 0 is the glass and the = is the light going through and < or > is the light coming out.

=0>< It will go through straight, focus in to a point but as the light goes farther it will cross in on it's self and go wider. Not a good description, but it should show the point. Anyways, colorful lasers look pretty.

A laser isn't just really intense light. Laser light is coherent, which means that the photons that make it up all have the same frequency, phase, and polarization. Sunlight, like light from a light bulb, is incoherent, and sending it through a magnifying lense won't help in that respect. Laser light, and all coherent light, behaves substantially differently than incoherent light. It is also produced in a different way than the light from a lightbulb or the sun. Although, we do use lenses to manipulate laser light.

reply to post by OnceReturned


Thanks! It was just a question I had thought about. I will star your replies because I feel that each one was a good simple answer.

Yeah, lasers have a lot of properties sunlight and other light sources do not have.

As already said it is coherent.
Laser light consists of one pure frequency only, sunlight is a confused jumble of many frequencies.
Laser light forms a very narrow parallel beam, that is otherwise very difficult to do.