Scientists develop 'tractor beam'
A real-life miniature version of the "tractor beam" featured in the Star Trek series has been created by a team of scientists which could be used in medical testing.
Although light manipulation techniques have existed since the 1970s, researchers said this is the first time a light beam has been used to draw objects towards the light source, albeit at a microscopic level.
In the science fiction show, a tractor beam was a method of using a beam of light to pull spaceships and other large objects.
The team from the University of St Andrews and the Institute of Scientific Instruments (ISI) in the Czech Republic said they have found a way to generate a special optical field that efficiently reverses radiation pressure of light. It is hoped it could lead to more efficient medical testing, such as in the examination of blood samples.
The researchers said they have discovered a technique which will allow them to provide negative force acting upon minuscule particles.
Normally when matter and light interact, the solid object is pushed by the light and carried away in the stream of photons. Such radiation force was first identified by Johanes Kepler when observing that tails of comets point away from the sun.
Over recent years researchers have realised that while this is the case for most optical fields, there is a space of parameters when this force reverses.
The team, led by Dr Tomas Cizmar, research fellow in the school of medicine at the University of St Andrews, with Dr Oto Brzobohaty and Professor Pavel Zemanek, both of ISI, said they have now demonstrated the first experimental realisation of this concept together with a number of applications for bio-medical photonics and other discipline.
Dr Cizmar said: "Because of the similarities between optical and acoustic particle manipulation, we anticipate that this concept will provide inspiration for exciting future studies in areas outside the field of photonics."
Prof Zemanek said: "The whole team have spent a number of years investigating various configurations of particles delivery by light. I am proud our results were recognised in this very competitive environment and I am looking forward to new experiments and applications. It is a very exciting time."