Quantum optics using Rydberg polaritons

The smallest amount of light is known as a photon. Although photons are plentiful, controlling them one-by-one remains challenging. If we could gain more control we could make tremendous advances in many areas including imaging, sensing, computing and communications.

In this project, we aim to gain more control over individual photons using a special type of atom known as a Rydberg atom. In a Rydberg atom, one electron is excited to a state where it is on average very far from the nucleus. In this Rydberg state, the atom has greatly exaggerated properties. In particular, it becomes extremely sensitive to nearby Rydberg atoms. Over the last decade in Durham, we have shown how to map this sensitivity between Rydberg atoms into a strong interaction between photons. This idea, known as Rydberg quantum optics, has resulted in the strongest interaction between photons ever demonstrated.

The next steps on this Rydberg quantum optics journey is to make this system more useful. A major step change in utility that we are proposing is to combine the remarkable features of Rydberg quantum optics with the power of integrated photonics. We will use a fibre coupled chip-based architecture to project single photons on demand and control the interactions between photons. In addition, we will show how these devices can be interfaced with cold atom based quantum memories.

Another important challenge to make Rydberg photonics technologically relevant is to make underlying physics and potential devices work faster. Currently the speed limit is in the range of Mbits per second. In this project, we will explore what happens when we try to extend this into the Gbits per second range. As well as increase data rates, going faster also has another advantage in that we become less sensitive to atomic motion which is currently one of the processes that degrade efficiency.

The steps demonstrated in this proposal will facilities significant progress towards the dream of a quantum internet.