Discovery of a new way to manipulate light a million times more efficiently

Using a special hollow-core photonic crystal fibre, a team at the University of Bath, UK, has opened the door to what could prove to be a new sub-branch of photonics, the science of light guidance and trapping.

The team, led by Dr Fetah Benabid, reports on the discovery, which relates to the emerging attotechnology, the ability to send out pulses of light that last only an attosecond, a billion billionth of a second.

These pulses are so brief that they allow researchers to more accurately measure the movement of sub-atomic particles such as the electron, the tiny negatively-charged entity which moves outside the nucleus of an atom. Attosecond technology may throw light, literally, upon the strange quantum world where such particles have no definite position,only probable locations.

To make attosecond pulses, researchers create a broad spectrum of light from visible wavelengths to x-rays through an inert gas. This normally requires a gigawatt of power, which puts the technique beyond any commercial or industrial use.

But Dr Benabid’s team used a photonic crystal fibre (pcf), the width of a human hair, which traps light and the gas together in an efficient way. Until now the spectrum produced by photonic crystal fibre has been too narrow for use in attosecond technology, but the team have now produced a broad spectrum, using what is called a Kagomé lattice, using about a millionth of the power used by non-pcf methods.

“This new way of using photonic crystal fibre has meant that the goal of attosecond technology is much closer," said Dr Benabid, of the University of Bath’s Department of Physics, who worked with students Mr Francois Couny and Mr Phil Light, and with Dr John Roberts of the Technical University of Denmark and Dr Michael Raymer of the University of Oregon, USA.

“The greatly reduced cost and size of producing these phenomenally short and powerful pulses makes exploring matter at an even smaller detail a realistic prospect.”

Dr Benabid’s team has not only made an important step in applied physics, but has contributed to the theory of photonics too. The effectiveness of photonic crystal fibre has lain so far in its exploitation of what is called photonic band gap, which stops photons of light from “existing” in the fibre cladding and enabled them to be trapped in the inside core of the fibre.

Instead, the team makes use of the fact that light can exist in different ‘modes’ without strongly interacting. This creates a situation whereby light can be trapped inside the fibre core without the need of photonic bandgap. Physicists call these modes bound states within a continuum.

The existence of these bound states between photons was predicted at the beginning of quantum mechanics in the 1930s, but this is the first time it has been noted in reality, and marks a theoretical breakthrough.

Source: University of Bath

Brightening the future for optical circuits
(PhysOrg.com) -- By working together to share costs and know-how, European researchers are shaking up the way research and development is carried out on optical chips.
European light research opens door for optical storage and computing
The goal of replacing electronics with optics for processing data in computers is coming closer through cutting edge European research into the mysterious properties of “fast and slow” light. The long term aim is to boost processing speeds and data storage densities by several orders of magnitude and take the information technology industry into a new era, combining greatly improved performance with dramatically lower energy consumption.
Optical fibre: secure in all the chaos
Secure messages hidden in chaotic waveforms, transmitted at up to 10 gigabits per second, is the vision behind a group of dedicated European researchers. Now they are prototyping the equipment that could make the vision a reality.
Discovery cuts cost of next generation optical fibers
Scientists have discovered a way of speeding up the production of hollow-core optical fibres - a new generation of optical fibres that could lead to faster and more powerful computing and telecommunications technologies.
Team develops tiny optical switch
A team of researchers at the University of St. Andrews has developed one of the smallest optical switches ever made.
Utra-fast fibre lasers, dopey photons... what’s next?
When lasers were developed in the 1960s, they were a solution looking for a problem to solve. Since then, they have become an essential tool in industries as diverse as nanotechnology and biomedicine. A new generation of ultra-fast fibre lasers being developed in Europe is creating even more uses for the beams of high-intensity light, while lowering production and maintenance costs and increasing efficiency.
Light sheds on new fibre's potential to change technology
Photonic crystal fibre’s ability to create broad spectra of light, which will be the basis for important developments in technology, has been explained for the first time in an article in the leading science journal Nature Photonics.
Trapped rainbow: New technique to slow down, stop and capture light offers bright future for internet, powerful computer
Professor Ortwin Hess, his PhD student Kosmas Tsakmakidis of the Advanced Technology Institute and Department of Physics at the University of Surrey and Professor Alan Boardman from Salford University have revealed a technique which may be able to slow down, stop and capture light.

Discovery of a new way to manipulate light a million times more efficiently

Related stories:

News discussion: