Speaker
Description
Optical cavities are among the most powerful tools for enhancing atom–light coupling and constitute a key building block for future quantum technologies based on light–matter interfaces. Rydberg atoms, with their strong and tunable interactions, are a particularly attractive non-linear medium for such interfaces. We present the design and construction of a low-finesse, rectangular, traveling-wave (“ring”) cavity integrated with our existing 87Rb Rydberg experiment operating on the D2 line at 780 nm, with the goal of enhancing the atom–light interaction and decreasing the decoherence rate of the existing setup.
The resonator is a macroscopic cavity located outside the vacuum chamber and consists of four planar mirrors and two intra-cavity lenses that form the cavity waist. This design is straightforward to implement and avoids the astigmatism that arises from a non-zero angle of incidence on spherical mirrors. The traveling-wave geometry removes the standing- wave modulation of a linear resonator, while the lenses ease the alignment procedure and can be placed close to the existing vacuum chamber to create a tight focus of about 5 µm. The non-planar geometry additionally allows independent control of the transverse-mode structure and the polarization eigenmodes, enabling nearly circularly polarized eigenmodes. The cavity is actively stabilized to a 787 nm laser that is in turn locked to an ultra-stable Fabry–Perot reference cavity.
Based on our current design and data from the existing experiment, we anticipate a collective cooperativity of about 100. This platform opens a route toward cavity-mediated interactions between Rydberg atoms, combining the enhanced coupling of a small-waist ring cavity with the strong, long-range interactions of Rydberg states.