A Brillouin Laser Optical Atomic Clock

TL;DR

This paper demonstrates a portable optical atomic clock using a compact SBS laser interrogating a Sr+ ion, achieving high stability and promising applications in precise geodetic measurements and GPS technology.

Contribution

It introduces a miniaturized SBS laser-based optical clock with enhanced stability, suitable for portable and field applications, advancing the transition of optical clocks outside laboratory settings.

Findings

Achieved a short-term stability of 3.9 x 10^-14 at 1 second.

Utilized a self-referencing technique to stabilize the SBS laser against temperature drift.

Demonstrated potential for 100-fold improvement in GPS distance measurement resolution.

Abstract

Over the last decade, optical atomic clocks have surpassed their microwave counterparts and now offer the ability to measure time with an increase in precision of two orders of magnitude or more. This performance increase is compelling not only for enabling new science, such as geodetic measurements of the earth, searches for dark matter, and investigations into possible long-term variations of fundamental physics constants but also for revolutionizing existing technology, such as the global positioning system (GPS). A significant remaining challenge is to transition these optical clocks to non-laboratory environments, which requires the ruggedization and miniaturization of the atomic reference and clock laser along with their supporting lasers and electronics. Here, using a compact stimulated Brillouin scattering (SBS) laser to interrogate a $^8$$^8$Sr$^+$ ion, we demonstrate a promising component of a portable optical atomic clock architecture. In order to bring the stability of the SBS laser to a level suitable for clock operation, we utilize a self-referencing technique to compensate for temperature drift of the laser to within $170$ nK. Our SBS optical clock achieves a short-term stability of $3.9 \times 10^{-14}$ at $1$ s---an order of magnitude improvement over state-of-the-art microwave clocks. Based on this technology, a future GPS employing portable SBS clocks offers the potential for distance measurements with a 100-fold increase in resolution.