Towards continuous spectroscopy and superradiance

Superradiance, a collective phenomenon that enables lasing from narrow clock transitions, holds great promise for active optical clocks. We present two experimental setups designed for continuous superradiance.

In our setup, we focus on continuous superradiance with ultracold ${\rm ^{88}Sr}$ atoms on the ${\rm ^1S_0\rightarrow ^3P_0}$ clock transition, achieved by opening the transition with a magnetic field. Superradiant emission is simulated using parameters inspired by our apparatus\footnote{ S. Dubey \emph{et al.}, arXiv:2409.06575 (2024).}. Experimentally, we aim to achieve continuous operation by spatially, rather than temporally, separating the laser cooling steps\footnote{ C. Chun-Chia, \emph{et al.}, Nature \textbf{606}, 683–687 (2022).}. We also propose an advanced loading scheme for quasi-continuous, long-distance transport, based on a two-stage MOT combined with a Bloch accelerator technique. Towards this goal, we are exploring a new method of position-dependent spectroscopy with our second-stage MOT and combining it with a new generation of frequency comb to create a long-term stable $10~{\rm MHz}$ source.