• Question: If the objects you are taking images of are really small, wouldn't the speed be affected by the laser itself?

    Asked by michaelplease to Tim on 23 Jun 2012.
    • Photo: Tim Stephens

      Tim Stephens answered on 23 Jun 2012:

      Great question!
      Light can exert a force on objects, and there have been some researchers working on using lasers as ‘tweezers’. I’m sure that a google search for “laser tweezers” would turn up some links to their research.
      The lasers that are used for laser tweezers are (I think) much more intense than the lasers that I use, and the particles that they are able to manipulate are quite a bit smaller than the ones that I normally image. So, whilst there will be some effect on the objects, it will be so small that it can be completely ignored compared with the effect of things like gravity and air currents in the laboratory.

Comments

  • Photo: stinley

    stinley commented on :

    this is called the uncertainty principle. say that you were using radiation to find the position of a subatomic particle and you used a gamma ray you could find the position easily but the high frequency radiation would change the speed and direction. If you used a radio wave then you could find out the speed and direction but it would be difficult to find the position.