• Question: what type of lasers do you use to observe gravitational waves?

    Asked by Shaisky to David on 23 Jun 2016.
    • Photo: David Robertson

      David Robertson answered on 23 Jun 2016:

      We need lasers that don’t change much with time, so their brightness and wavelength have to be very stable. For the space mission we use a NPRO Nd:YAG laser with a wavelength of 1064nm, and a power of 50mW 🙂

      What all that means is that the laser is actually a fancy crystal, about the size of your thumbnail with some magnets to make it run properly and some diode lights to power it. The laser light is invisible and has a wavelength of about 1micron (a thousandth of a mm).

      NPRO stands for Non-Planar Ring Oscillator which is to do with the shape of the laser crystal.

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