London Press Service
COMING SOON? – COMPUTERS THAT RUN ON LIGHT
The dream of creating photonic computers – devices that are run by using light rather than electronics – and getting them on to the desktop has got a step closer to reality with the start of a research project later this year.
Physicists at the University of Bath, England, are to look at developing attosecond technology, the ability to send out light in a continuous series of pulses that last only an attosecond, one billion-billionth of a second.
The research could not only develop the important technology of photonics but could give physicists that chance to look at the world of atomic structure very closely for the first time.
In June 2007, Dr. Fetah Benabid, of the Department of Physics at Bath, will lead a team of researchers to develop a new technique that would enable them to synthesise waveforms using light photons with the same accuracy that electrons are used in electronics.
Waveform synthesis is the ability to control very precisely the way that electric fields vary their energy.
The research is funded by a grant of 820,000 pounds from the UK’s Engineering & Physical Sciences Research Council. “Harnessing optical waves would represent a huge step, perhaps the definitive one, in establishing the photonics era,” said Dr. Benabid. “If successful, the research will be the basis for a revolution in computer power as dramatic as that over the past 50 years.
“Since the development of the laser, a major goal in science and technology has been to emulate the breakthroughs of electronics by using optical waves. We feel this project could be a big step in this.”
Ordinarily, electric fields rise and fall in energy in a regular pattern similar to the troughs and crests of waves on the ocean, but modern electronics allows a close control over the shape of the “wave” – in effect creating waves that are square or triangular or other shapes rather than curved.
It is this control of the variation of the electric field that allows electronic devices such as computers to function in the precise way needed.
But electronics has its limitations, and the development of ever-smaller silicon chips that has allowed computers to double in memory size every 18 months or so will come to an end in the next few years because the laws of physics do not permit chips smaller than a certain size.
Instead, engineers are looking to the science of photonics – that uses light to convey information – as a much more powerful alternative. But up to now, photonics can use light whose waveform is in one shape only – a curve known as a sine wave – and this has limited value for the communications needed to run a computer, for example.
The Bath University researchers want to allow photonics to create waveforms in a variety of patterns. To do this, they are using the new photonic crystal fibres that are a great step forward in photonics because, unlike conventional optical fibres, they can channel light without losing much of its energy.
In the research, light of one wavelength will be passed down a photonic crystal fibre that then branches off in a tree-like arrangement of fibres, each with a slightly separate wavelength, creating a broad “comb-like” spectrum of light from ultraviolet to the middle of the infrared range.
This broad spectrum would allow close control over the electric field that is the basis of conveying enormous amounts of information that modern devices such as computers need.
“Harnessing optical waves would represent a huge step, perhaps the definitive one, in establishing the photonics era,” said Dr. Benabid. “Since the development of the laser, a major goal in science and technology has been to emulate the breakthroughs of electronics by using optical waves.
“We feel this project could be a big step in this. If successful, the research will be the basis for a revolution in computer power as dramatic as that over the past 50 years.”
Dr. Benabid explained that the technology that could be built if his research is successful could, for instance, make lasers that operate at wavelengths that today’s technology cannot now create and which would be important for surgery.
The continual series of short bursts of light would not only dramatically affect technology, it would also advance physics by giving researchers the chance to look inside the atom.
Although atoms can now be “seen” using devices such as electron microscopes, it has not been possible to examine their fast dynamics.
By sending the light in short bursts into an atom, researchers would be able to work out the movements of electrons, the tiny negatively charged particles that orbit the atom’s nucleus.
This may throw light, literally, on the strange quantum world of sub-atomic particles that have no definite position but are only “probably” in one place until observed.
By Richard Maino