World’s shortest light pulse contains just one photon
April 11, 2008
The world’s shortest light pulse containing just one photon has been produced by Oxford Univ. scientists.
The Oxford team can create individual photons that are 65 femtosecs in duration: that’s approximately fifty times shorter than any single photon previously produced. And every photon this source produces is identical to the previous one. Such photons could be a major breakthrough in quantum computing: the harnessing of quantum effects to perform calculations that would take conventional computers thousands of years to resolve.
“Creating single photons even under controlled conditions is extremely challenging,” says Peter Mosley of Oxford’s Dept. of Physics. “Even the purest laser light beam consists of many photons all bunched together. Our approach enables us to generate individual photon replicas, identical packets of light of very short duration that are ideal for quantum computing.”
Peter Mosley, a member of Oxford’s Ultrafast Group, is a co-author of a report of the research in this week’s Physical Review Letters.
He says that in a quantum information device based on light (where photonic logic gates replace electronic ones), having a stream of identical, high-quality single photons on tap is vital. “It is possible to make photons in pairs by sending laser light through special crystals. When a pair has been created, the detection of one of these photons heralds the presence of its twin. However these twin photons are entangled, meaning that the properties of one photon are inextricably linked to those of its partner and detecting one can ruin the quantum state of the other,” says Mosley.
“Our technique minimizes the effects of this entanglement, enabling us to prepare single photons that are extremely consistent and, to our knowledge, have the shortest duration of any photon ever generated. Not only is this a fascinating insight into fundamental physics but the precise timing and consistent attributes of these photons also makes them perfect for building photonic quantum logic gates and conducting experiments requiring large numbers of single photons.”
In the Oxford experiment the pairs of photons made had a central wavelength of about 830 nm, at the border between visible and near-infrared light. Each of these photons was about 65 femtosecs (65 millionths of a billionth of a second) long. In units of space, they were about 20 µm long. The shortest previously produced single photon was about 1 picosecond long.
Oxford’s Ultrafast Group: http://ultrafast.physics.ox.ac.uk/
Oxford Science Blog: http://www.ox.ac.uk/media/science_blog/index.html
SOURCE: Oxford Univ.
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The Oxford team can create individual photons that are 65 femtosecs in duration: that’s approximately fifty times shorter than any single photon previously produced. And every photon this source produces is identical to the previous one. Such photons could be a major breakthrough in quantum computing: the harnessing of quantum effects to perform calculations that would take conventional computers thousands of years to resolve.
“Creating single photons even under controlled conditions is extremely challenging,” says Peter Mosley of Oxford’s Dept. of Physics. “Even the purest laser light beam consists of many photons all bunched together. Our approach enables us to generate individual photon replicas, identical packets of light of very short duration that are ideal for quantum computing.”
Peter Mosley, a member of Oxford’s Ultrafast Group, is a co-author of a report of the research in this week’s Physical Review Letters.
He says that in a quantum information device based on light (where photonic logic gates replace electronic ones), having a stream of identical, high-quality single photons on tap is vital. “It is possible to make photons in pairs by sending laser light through special crystals. When a pair has been created, the detection of one of these photons heralds the presence of its twin. However these twin photons are entangled, meaning that the properties of one photon are inextricably linked to those of its partner and detecting one can ruin the quantum state of the other,” says Mosley.
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In the Oxford experiment the pairs of photons made had a central wavelength of about 830 nm, at the border between visible and near-infrared light. Each of these photons was about 65 femtosecs (65 millionths of a billionth of a second) long. In units of space, they were about 20 µm long. The shortest previously produced single photon was about 1 picosecond long.
Oxford’s Ultrafast Group: http://ultrafast.physics.ox.ac.uk/
Oxford Science Blog: http://www.ox.ac.uk/media/science_blog/index.html
SOURCE: Oxford Univ.
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