• Question: What is the power of a lser measured in?

    Asked by 10mihalcioiub to Mike, Pip, Tianfu, Tim, Tom on 2 Jul 2012.
    • Photo: Tim Stephens

      Tim Stephens answered on 2 Jul 2012:

      It depends on the laser.
      Usually we measure Watts which is the amount of energy delivered divided by the time that the energy is delivered over.
      For lasers with very short pulses, this doesn’t make sense because the number of Watts you get is very very high. Instead, we would use the total amount of energy in a single pulse to describe how powerful the laser is – this is measured in Joules.

    • Photo: Tom Lister

      Tom Lister answered on 2 Jul 2012:

      Good answer Tim. Our ‘continous’ lasers put out about 0.5 Watts, which is much less than the light bulbs in my house. They can cut through skin though.

      The pulsed ones are around about 10 J per pulse, which fired at a rate of twice per second is about 20W on average (although the instant power is very high, like Tim said).

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