Using mirrors to improve the quality of light particles

September 11, 2017

Scientists from the University of Basel's Department of Physics and the Swiss Nanoscience Institute have succeeded in dramatically improving the quality of individual photons generated by a quantum system. The scientists have successfully put a 10-year-old theoretical prediction into practice. With their paper, published recently in Physical Review X, they have taken an important step towards future applications in quantum information technology.

For a number of years, scientists have been working on using electron spins to store and process information. A possible approach is to use a quantum system in which the quantum state of the electron spin is linked to that of the emitted light particles (photons).

Nitrogen vacancy centers (NV centers) are considered a proven structure for this approach, allowing electron spins to be read and manipulated easily. These NV centers are natural defects in the crystal lattice of diamond, over which researchers have gained control over the last decades.

Better photons are needed

NV centers are particularly interesting in the field of quantum information processing, as they emit individual photons that carry information about the state of their electron spin. These photons in turn can create quantum entanglement between various NV centers; this entanglement can be established even over large distances and can thus be used for data transmission.

However, for applications in quantum information technology, significant improvements will be needed in the quantity and above all the quality of the emitted photons, since so far only a fraction of the photons can be used to produce entanglement.

Successful optimization

Doctoral student Daniel Riedel has now succeeded in boosting the yield of useful photons from these NV centers from 3% to a current value of 50%. In addition, he has been able to almost double the rate at which the photons are emitted.

Riedel achieved these significant improvements by placing a nanofabricated piece of diamond, measuring just a few hundred nanometers across, between two tiny mirrors. It had already been described theoretically 10 years ago that the placement of NV centers inside a cavity ought to increase the yield of photons. Until now, however, no research group had managed to put this theory into practice.

The paper emerged as part of a doctoral thesis at the Swiss Nanoscience Institute's PhD School, which was established in 2012. "We have overcome an important hurdle on the path towards the quantum internet," says supervisor Professor Richard Warburton of the Department of Physics at the University of Basel.

Professor Patrick Maletinsky, who also supervised the work, adds: "The unique combination of expertise in the field of photonics, special diamond structures and nanofabrication here in Basel meant it was possible to overcome this 10-year-old challenge for the first time."
-end-


University of Basel

Related Photons Articles from Brightsurf:

An electrical trigger fires single, identical photons
Researchers at Berkeley Lab have found a way to generate single, identical photons on demand.

Single photons from a silicon chip
Quantum technology holds great promise: Quantum computers are expected to revolutionize database searches, AI systems, and computational simulations.

Physicists "trick" photons into behaving like electrons using a "synthetic" magnetic field
Scientists have discovered an elegant way of manipulating light using a ''synthetic'' Lorentz force -- which in nature is responsible for many fascinating phenomena including the Aurora Borealis.

Scientists use photons as threads to weave novel forms of matter
New research from the University of Southampton has successful discovered a way to bind two negatively charged electron-like particles which could create opportunities to form novel materials for use in new technological developments.

The nature of nuclear forces imprinted in photons
IFJ PAN scientists together with colleagues from the University of Milano (Italy) and other countries confirmed the need to include the three-nucleon interactions in the description of electromagnetic transitions in the 20O atomic nucleus.

Pushing photons
UC Santa Barbara researchers continue to push the boundaries of LED design a little further with a new method that could pave the way toward more efficient and versatile LED display and lighting technology.

Photons and electrons one on one
The dynamics of electrons changes ever so slightly on each interaction with a photon.

An advance in molecular moviemaking shows how molecules respond to two photons of light
Some of the molecules' responses were surprising and others had been seen before with other techniques, but never in such detail or so directly, without relying on advance knowledge of what they should look like.

The imitation game: Scientists describe and emulate new quantum state of entangled photons
A research team from ITMO University, MIPT and Politecnico di Torino, has predicted a novel type of topological quantum state of two photons.

What if we could teach photons to behave like electrons?
The researchers tricked photons - which are intrinsically non-magnetic - into behaving like charged electrons.

Read More: Photons News and Photons Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.