CQT PhD Thesis Defense by Adam Florentin Thierry
Title: Vacuum Rabi Splitting In A Compact Near-Concentric Cavity
Date/Time: 07-May, 04:30PM
Venue: CQT Level 3 Conference Room, S15-03-17
Abstract:The exploration of strong atom--light interaction is crucial as a building block for engineering quantum computing nodes. Such nodes can be realised with atoms, which require mediators to enhance their interaction with incoming photons, due to their small cross-section. Optical cavities, tools governed by cavity quantum electrodynamics (cavity-QED), fulfil this mediator role by confining the photons in a small mode volume. While a small mode volume can be implemented in conventional high-finesse optical cavities, less-explored configurations, such as near-concentric cavities, also exhibit this feature. Near-concentric cavities provide a unique balance of a small mode volume and significant optical access for atom manipulation, while only requiring low finesse to operate. However, it is sensitive to misalignment when operating close to the concentric regime.
We present a near-concentric optical cavity system to address this longitudinal and transverse stability close to the concentric regime. The cavity system features a compact cage-like tensegrity mirror support structure, with a cavity length of 11mm. We demonstrate the low residual cavity length variation of the structure at a close critical distance from the concentric regime, while allowing control of all necessary degrees of freedom. With this stability, we observe the vacuum Rabi splitting in the presence of ten trapped atoms. This measurement showcases the ability of our atom–cavity system to reach the strong coupling regime.
This near-concentric cavity geometry provides a viable alternative to near-planar cavity geometries for cavity-QED experiments. One notable advantage is its high optical access to the centre of the cavity mode, beneficial for atomic state preparation in quantum information processing schemes. Leveraging the mechanical stability and strong interaction capabilities of the developed near-concentric cavity opens up new possibilities for implementing quantum logic gates with low-finesse resonators.