Year: 2026
Type: preprint
Abstract: Portable atomic clocks are essential in a wide variety of applications, most notably in the operation of global navigation satellite systems. Existing portable atomic clocks utilizing microwave-based interrogation schemes are now routinely eclipsed by the next generation of atomic frequency standards based on optical interrogation. While optical frequency standards demonstrate greatly improved frequency stability, they have only recently reached a level of technical maturity required to demonstrate this improved performance outside of well curated laboratory environments. Here, we demonstrate a fully autonomous and portable optical frequency standard based on an efficient dual-color excitation of the $5S_{1/2}\rightarrow5D_{5/2}$ two-photon transition in $^{87}$Rb. The standard utilizes a combination of robust, highly developed commercial-off-the-shelf telecommunications technologies and a fully integrated portable optical frequency comb, providing the optical and microwave outputs vital for interfacing with existing electronic systems and infrastructure. The system demonstrates a fractional frequency stability of $1.9\times10^{-13}$ at 1s of integration time, reaching $3.5\times10^{-15}$ at 8000s of integration time without the need for drift removal. This portable demonstrator unit marks a significant achievement in the development of Rb optical atomic frequency standards, and for the deployment of optical atomic frequency standards outside of the laboratory.
Source: arXiv (Cornell University)
Institutions: Adelaide University, The University of Adelaide
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: Australian National Fabrication Facility, Australian Government, Asian Office of Aerospace Research and Development, Department of Science and Technology, Ministry of Science and Technology, India, National Institute of Standards and Technology, Defence Science and Technology Group, Air Force Office of Scientific Research
Awards: G2365865096, G3591598716
OpenAlex ID: W7212075016