• Question: How do lasers work?

    Asked by Galaxies to Sarah, Connor, Jillian, Lidunka, Steven on 15 Jun 2015. This question was also asked by Winnie, wolf spirit ( Ox0), Florence.
    • Photo: Sarah Beasley

      Sarah Beasley answered on 15 Jun 2015:

      Hey 🙂 Hmm, where to start!

      The word LASER is actually an acronym; it stands for Light Amplification by Stimulated Emission of Radiation.

      When certain materials absorb a photon, an electron gets excited into a different energy band. This can randomly then emit a photon again, which is called ‘spontaneous emission’. The ‘stimulated’ emission is what lasers use, where we can actually control when the photos are given off.

      Lasers are basically machines that take billions of atoms, and pump out trillions of photons (particles of light) so that they all line up into a really concentrated light beam. It’s essentially a tube with a mirror at each end, but one of the mirrors isn’t as good at reflecting light as the other one, so that’s the end which lets the laser light out.

      The important bit to remember is that laser light is monochromatic, which means all similar wavelengths, coherent, which means they’re all at the same angle (phase), and collimated, so in parallel waves.

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