ESR13-Thilina Muthu Arachaige

Thilina Muthu Arachaige

Optical non linearities with Rydberg atoms in an optical high finesse cavity.

My project

My task at the Surface Quantum optics group in Tubingen is to investigate the optical nonlinear behaviour arising from interaction between light fields in optical cavities and atoms with long-range interactions. To achieve this, we plan to employ a cloud of highly excited atoms, i.e. Rydberg atoms trapped inside a high finesse optical cavity. The findings are very beneficial to generate non-classical states of light and realize efficient quantum memories which are key components in quantum networks and quantum information processing.

Research focus

Our research focuses on reaching the quantum nonlinear regime in interacting light atom systems. Using Rydberg states of the atoms enables us to preserve the nonlinearity in our system via Rydberg blockade. The high finesse cavity extends our system to the quantum nonlinear regime. Thus, in developing the experimental setup, we will start with the preparation of the Rydberg atomic cloud in a high finesse optical cavity. The first goal is to observe strong coupling of light and Rydberg states in the optical cavity. Next we plan to investigate the Rydberg blockade followed by generation of non-classical states of light with Rydberg atoms.

Networking Opportunities

In order to develop the experiment I’m involved, I will use the rich knowledge and the expertise on both theory and experiments in cold Rydberg atoms available within the ColOpt network. This is planned both by attending the network meetings, and by research visits to industrial partner Toptica photonics in Munich (Germany), and research stays at University of Wisconsin in Madison (USA) on experiments with Rydberg atoms and University of Saarland (Germany) on atom-cavity theory. Moreover, we will collaborate with groups at University Tubingen as well.

Outcomes and Impact

The novelty in our project is the optical high finesse cavity in which the cloud of Rydberg atoms are trapped in. So far, only two groups have studied Rydberg atoms in optical cavities (moderate and low finesse) which lacked enough cooperativity to reach the quantum regime. Our approach promises sufficient enough cooperativity to reach the quantum regime while preserving the non-linearity. This will enable us to realize and implement not only efficient quantum memories, but also to generate non-classical states of light and combine with superconducting atom chips for quantum computing applications.



I did my bachelor studies in electrical engineering at Riga Technical University, Latvia.

In 2017, I completed master studies in Optics and nanoscience at Ecole Polytechnique and University Paris-Sud in France. Following the French system, I did two research internships, each for 1st and the 2nd year of the master at Laboratoire Kastler-Brossel (ENS-UPMC-College de France) in Paris.

For master 1, a 5 months internship working on a free space quantum memory with Caesium atoms and for master 2, following my interest in nanoscience, a 6 months internship investigating quantum fluids in micro-cavity polariton systems