Progress on Optical Clock Technology for Operational Timescales

TL;DR

This paper discusses recent progress in developing optical clock technology for continuous, long-term operational use, including hybrid clocks and atomic beam optical clocks, to improve timekeeping stability and reliability.

Contribution

It introduces new developments in optical clock integration for operational timescales, enabling continuous, high-precision timekeeping without reliance on traditional masers.

Findings

Hybrid clock with optical stability and long-term reference demonstrated.

Atomic beam optical clocks support 24/7 operations with improved performance.

Development of an optical lattice as a frequency standard is underway.

Abstract

While optical clock technology has advanced rapidly in recent years, incorporating the technology into operational timescales has progressed more slowly. The highest accuracy frequency standards for groundbreaking measurements do not easily translate to critical timing where continuous, uninterrupted operation over many months and years is required. For example, intermittent steering of a hydrogen maser with an optical standard fails to harness all of the dramatic improvements possible with optical technology. Here we present progress on development and integration of optical-clock technology for operational timescales. An optical oscillator steered to an atomic fountain comprises a hybrid clock with optical-level stability at short times and a reliable long-term reference, and obviates the need for a steered maser. Atomic beam optical clocks are being developed to support 24/7 operations at a level that improves upon the performance of the U.S. Naval Observatory's rubidium fountains. An optical lattice is being developed as a gold-standard frequency reference, complementing the role of the atomic beam clocks.