• Question: What sort of lazers do you use? (how powerfull? what do they do?)

    Asked by jordanikin to Allan, Angela, Diva, Harriet, Nathan on 27 Jun 2012. This question was also asked by rosiep.
    • Photo: Diva Amon

      Diva Amon answered on 27 Jun 2012:

      Hey jordanikin,
      In deep-sea biology, we only use lasers for one thing. Because the deep sea is so far down in the ocean, it means that there are really high pressures, cold temperatures and no light. This means that humans cant scuba dive down there themselves so now we use robots called Remotely Operated Vehicles (ROVs). These robots are extremely high tech – they have very powerful lights so we can see, lots of sensors so we can measure things, thrusters so we can drive them around and even manipulator arms so we can pick up animals and samples. There are also two lasers on our ROV which are fixed exactly 10 cm apart and shine outwards onto what the camera (and us) can see. Because they are perfectly 10cm apart, the two red laser light dots are also 10cm apart no matter what they shine on. This means that we can see how large what we are looking at is as the laser lights can be used to give a sense of scale. Kind of like a reference point. They aren’t very powerful but this is on purpose so we don’t hurt any of the animals or environments which we are investigating.

    • Photo: Nathan Langford

      Nathan Langford answered on 27 Jun 2012:

      Hi jordanikin,

      I used to be a laser physicist and we used lots of different types of lasers for lots of different reasons. I’ve used UV lasers (to make things fluoresce and to pump crystals), blue, green and red lasers (sometimes just for aligning beams, but sometimes also to make things absorb light) and also infrared lasers (mostly just to align things, but sometimes also to make other colours, like green).

      I’ve used gas lasers (like Helium-Neon lasers to trap small particles under a microscope and move them around using laser tweezers), diode lasers (to send alignment beams all around my optical table), and solid state lasers (to produce very short pulses with very high powers).

      I’ve used weak lasers as small as a few picowatts of power (that’s one millionth of one millionth of a Watt) to probe fragile things without destroying them, and very high-power lasers (over 1W, which is already plenty strong enough to burn things – you’re normal laser pointer is about 1 milliwatt in power) to pump nonlinear crystals and create entangled photon pairs.

      I’ve also used “continuous-wave” lasers, which are one long stream of light, and ultrafast pulsed lasers, with pulses down to 50 femtoseconds long (1 femtosecond is 1 thousandth of 1 millionth of 1 millionth of a second long).

      Cheers,
      Nathan.

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