Entangled photon source is ’20 times brighter’
1 min read
A team from the Laboratoire de Photonique et de Nanostructures (LPN) of the French National Centre for Scientific Research CNRS has developed a light source for entangled photons said to be 20 times brighter than all existing systems.
The researchers have developed a 'photonic molecule' system in which a semiconductor quantum dot emits a pair of entangled photons per excitation pulse from a laser. This photonic molecule constitutes a trap for each of the photons of the pair and allows them to be collected efficiently. The source can generte one pair of photons for every eight pulses, compared to fewer than one pair every 100 pulses for other approaches. In the future, the researchers believe they should be able to reach a rate close to one pair of photons per pulse.
Using this device could make it possible to manufacture electroluminescent diodes of entangled photon pairs, with rates close to 1GHz. LPN scientists have also shown that the photonic molecule concept allows the quality of the entanglement of the emitted photon pairs to be improved.
Entanglement has far reaching application in fields such as quantum cryptography, quantum computation and quantum teleportation.
The image represents, in the top right hand corner, the new component produced in the LPN experiment: two pillars of micrometric size are coupled to form the 'photonic molecule'. The semiconductor quantum dot (of nanometric size) is inserted into one of the pillars (visible as the bright spot in the right hand pillar). The lower part of the image shows the radiation pattern of the entangled photons emitted by the component.
