• Question: What do the laser pulses that you work with look like?

    Asked by nebula to Ashley on 11 Nov 2015.
    • Photo: Ashley Hughes

      Ashley Hughes answered on 11 Nov 2015:

      Quite a difficult to imagine I guess.

      If you were to see the laser as it is in real life without aid you would see nothing – I use infrared light which is invisable to us! Have a look at the spectrum here… it is just outside of the visible region, but closest to red.

      The shape of the light is like a ball, a sphere, and they come one after another due to some very clever mirrors and a computer that times them. This means I get a pulse of light that lasts for 1 femtosecond, and this arrives every 250 microseconds, so you would also have to slow time down to be able to see it yourself.

      I hope this helps somewhat.

      For reference,

      A microsecond is 0.000001 or 10−6 (ten to the minus 6) seconds, and a femtosecond is rediculously small…. 10−15(ten to the minus 15) or 1/1,000,000,000,000,000 of a second. That is one quadrillionth, or one millionth of one billionth, of a second.

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