Fully Collective Superradiant Lasing with Vanishing Sensitivity to Cavity Length Vibrations

TL;DR

This paper proposes a superradiant laser system with multi-level atoms and auxiliary cavities that achieves ultra-narrow linewidths and extremely low sensitivity to cavity vibrations, advancing continuous atomic clock technology.

Contribution

It introduces a novel multi-level atomic scheme with collective pumping and decay, overcoming previous lasing threshold limitations and reducing vibration sensitivity to near zero.

Findings

Achieves an $ ext{O}(100 ext{ μHz})$ linewidth superradiant laser.

Demonstrates cavity vibration sensitivity below $ ext{O}(10^{-14}/g)$.

Identifies parameter regimes with zero vibration sensitivity at steady state.

Abstract

To date, realization of a continuous-wave active atomic clock has been elusive primarily due to parasitic heating from spontaneous emission while repumping the atoms. Here, we propose a solution to this problem by replacing the random emission with coupling to an auxiliary cavity, making repumping a fully collective process. While it is known that collective two-level models do not possess a generic lasing threshold, we show this restriction is overcome with multi-level atoms since collective pumping and decay can be performed on distinct transitions. Using relevant atomic parameters, we find this system is capable of producing an $\mathcal{O}$(100 $\mu$Hz)-linewidth continuous-wave superradiant laser. Our principal result is the potential for an operating regime with cavity length vibration sensitivity below $\mathcal{O}(10^{-14} / g)$, including a locus of parameter values where it completely vanishes even at steady-state.