Question: I am not quite sure how lasers are used for photography, can you please explain to me how it works.

Tim Stephens answered on 23 Jun 2012:

There are two properties of lasers that I use for photography.

The first is the fact that you can control a laser beam much better than ‘normal’ light. This means that I can spread the laser beam out into a fan shape to let me light up a sheet within the area that I want to take pictures of. An example would be if I had a flow of air with small droplets of oil in it. If the room is dark, I could use the laser to light up a plane within that flow and then use a camera to see only the oil droplets that are lit up by the laser. This lets me make measurement of how fast the droplets are moving by tracking them from one picture to the next.

The second thing that I use lasers for is the fact that they can be made to make very short flashes of light. If you want to take a picture of something moving very quickly with normal lights, it looks very blurred in the photograph because it moved whilst the camera was taking the picture. WIth a short, bright flash of laser light (and no normal lights), the object hasn’t moved as far whilst the camera was taking the picture so you can capture a much clearer picture. There’s a nice little example on this page on our company website http://www.oxfordlasers.com/imaging/high_speed that shows the difference between pulsed laser lighting and normal continuous lighting