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Optical tweezers on your iPad

By Hamish Johnston

Imagine if you could reach out with your hands and grab a microscopic object – and watch as you move it about with micron precision or even spin it round. You could, for example, assemble a machine out of tiny components or poke and probe a bacterium or two.

Well, now all you need is an iPad – and a connection to a holographic optical tweezers system – thanks to a new software application created by researchers at the University of Glasgow and University of Bristol.

Holographic optical tweezers use a spatial light modulator to split and steer a laser beam so that it can be used to manipulate multiple microscopic objects in 3D.

The challenge, however, is how to interface such an instrument with a human operator.

In December I saw a fantastic lecture by Mervyn Miles of the University of Bristol that offered one solution – a custom-built “multi-touch table” with a screen that displays a live microscope image from holographic optical tweezers. If you pinch your fingers round a micron-sized glass ball, you can grab it with the tweezers and move it to another location.

Now Miles and colleagues have transferred this technology to an Apple iPad – perhaps not the cheapest electronic gadget, but much less expensive than their bespoke table.

You can watch a demonstration in the above video and read all about the iPad app in this paper in the Journal of Optics.

Posted by Hamish Johnston on Mar 4, 2011 4:14 PM | Permalink