Physics
Glass Threads Cause Strong Connection Between Two Photons
Catherine Griffin
First Posted: Nov 03, 2014 12:45 PM EST
Scientists may have found a way to establish a strong connection between two single photons with the help of a glass fiber. The new method could open up completely new possibilities for quantum optics.
Normally, two photons in free space don't interact. Light waves can pass through each other without having any influence on each other at all. For many applications in quantum technology, though, interaction between photons is crucial.
In this case, the scientists built a system which creates a strong interaction between only two photons. In fact, this interaction is so strong that the phase of the photons is changed by 180 degrees. They managed this feat by using an ultra-thin glass fiber and coupling it to a tiny bottle-like light resonator so that light can partly enter the resonator, move in circles and return to the glass fiber.
When a single rubidium atom is coupled to the resonator, though, the system changes dramatically. Hardly any light enters the resonator anymore and the oscillation phase of the photon can't be inverted. When two photos arrive at the same time, things change.
"The atom is an absorber which can be saturated," said Arno Rauschenbeutel, one of the researchers, in a news release. "A photon is absorbed by the atom for a short while and then released into the resonator. During that time, it cannot absorb any other photons. If two photons arrive simultaneously, only one can be absorbed, while the other can still be phased shifted."
From a quantum mechanical point of view, there's no difference between these two photons. No one can tell which of the photons is being absorbed and which one has passed. When both hit the resonator at the same time, both experience a phase shift by 180 degrees.
"That way, a maximally entangled photon state can be created," said Rauschenbeutel. "Such states are required in all fields of quantum optics-in quantum teleportation, or for light-transistors which could potentially be used for quantum computing."
The findings are published in the journal Nature Photonics.
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First Posted: Nov 03, 2014 12:45 PM EST
Scientists may have found a way to establish a strong connection between two single photons with the help of a glass fiber. The new method could open up completely new possibilities for quantum optics.
Normally, two photons in free space don't interact. Light waves can pass through each other without having any influence on each other at all. For many applications in quantum technology, though, interaction between photons is crucial.
In this case, the scientists built a system which creates a strong interaction between only two photons. In fact, this interaction is so strong that the phase of the photons is changed by 180 degrees. They managed this feat by using an ultra-thin glass fiber and coupling it to a tiny bottle-like light resonator so that light can partly enter the resonator, move in circles and return to the glass fiber.
When a single rubidium atom is coupled to the resonator, though, the system changes dramatically. Hardly any light enters the resonator anymore and the oscillation phase of the photon can't be inverted. When two photos arrive at the same time, things change.
"The atom is an absorber which can be saturated," said Arno Rauschenbeutel, one of the researchers, in a news release. "A photon is absorbed by the atom for a short while and then released into the resonator. During that time, it cannot absorb any other photons. If two photons arrive simultaneously, only one can be absorbed, while the other can still be phased shifted."
From a quantum mechanical point of view, there's no difference between these two photons. No one can tell which of the photons is being absorbed and which one has passed. When both hit the resonator at the same time, both experience a phase shift by 180 degrees.
"That way, a maximally entangled photon state can be created," said Rauschenbeutel. "Such states are required in all fields of quantum optics-in quantum teleportation, or for light-transistors which could potentially be used for quantum computing."
The findings are published in the journal Nature Photonics.
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone