Scientists from Scotland and the Czech Republic have together created a miniature real-life "tractor beam" - a beam of energy that can attract one object to another from a distance - as was depicted in the Star Trek series. In this case, the researchers (from the University of St Andrews (Scotland) and the Institute of Scientific Instruments (ISI) in the Czech Republic) were able to use a light beam to draw microscopic objects toward the light source.
Normally, when matter and light interact, matter is pushed away by the radiation pressure of light, such as is observed with comet tails pointing away from the sun. However the scientists were able to generate a special optical field that reverses that effect, which produces a "negative" force acting upon the minuscule particles that causes them to be pulled against the photon stream.
This is claimed to be the first experimental realization of the concept of such a "negative" optical force. Further, according to the researchers, the force is very selective in the properties - such as size and composition - of the particles that it acts on, which could allow simple and inexpensive optical sorting of micro-objects.
Practical areas that could benefit from this research include biomedical applications and fields involving intricate engineering. For more information see the original article ("Experimental demonstration of optical transport, sorting and self-arrangement using a ‘tractor beam’"). Also see an article from Physics World ("Optical tractor beam sorts tiny particles") for more background details.
http://www.edn.com/electronics-blogs/tech-edge/4407095/Star-Trek-style--tractor-beam--is-created-on-tiny-scale
