Question: what is a laser made of?

Peta Foster answered on 16 Nov 2011:

A laser can be made from lots of things…. some are based on crystals, some on gases and some on liquid dyes.

The key thing to make a laser is you need a cavity which is made of two mirrors facing each other; something called the lasing material, which is the crystal which you place in between the mirrors and then you need a bright light to flash at the crystal.

Then what happens is the the bright light excites atoms in the crystal which then relax and emit light… some of this light will go in the direction of the mirrors and once it has it is reflected back into the crystal… now when the light that the crystal emitted travels back through the crystal is actually encourages the other atoms in the crystal to release their energy as light which is perfectly in step with the light encouraging them to do so… this is called stimulated emission and produces a beam of light where all the peaks are in the same place and all the troughs and in the same place…. like the way people march together in perfect step… so do the photons (packets of light). 🙂

Now if you want to get the laser light out to see it then you need to make one of the mirrors not perfectly reflecting so it leaks out a little bit and there is your laser! 😀

I hope this helps, great question! 😀