Quantum Photonics – Niels Bohr Institute - University of Copenhagen

Quantum Photonics

Quantum Photonics builds bridges between two areas of research: Quantum optics and nanophysics. The research is a combination of quantum optics, where you typically work with ultra-cold atomic gases and of nanophysics, where you work with solid-state matter.

The research group is focusing on developing techniques to control the quantum dynamic of a single quantum of light (a photon), which interacts with a single quantum of matter (an atom).

The solid matter the researchers are working with are so-called quantum dots, which are ‘artificial’ solid-state atoms. Quantum dots consist of thousands of atoms embedded in nano-photonic structures, so-called photonic crystals. In a photonic crystal, the interaction between a quantum dot and a single photon can be so powerful that quantum optical effects can be observed.

These artificial atoms have controllable energy levels that allow for the emission of one photon at a time. The photons are controlled by means of tailor made nano-photonic structures such as photonic crystals or plasmonic nanowires. Using these techniques it is possible to produce light sources that emit a single photon as needed or to entangle quantum dots and photons. Such nano-photonic units have the potential to be applied to quantum information.

The research will, among other things, pave the way for future quantum communication. If advanced quantum communication is to become a practical reality, you shouldn’t use ultra-cold atoms in a gaseous form, but rather in solid-state form, because computers are made up of electronic chips based on solid matter (semi-conducting materials).