Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Proceedings of the ... annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting/Proceedings of a meeting - Precise Time and Time Interval (PTTI) Systems and Applications Meeting

A Compact Optical Rubidium Atomic Frequency Standard

Gretchen R. Phelps, N. Lemke, Kyle W. Martin, Christopher Erickson, John H. Burke

Published Feb 26, 2016• 3 citations
Publisher

Abstract

Precision navigation and timing is an important focus in the Air Force Research Laboratory's experimental efforts. The development and testing of an optical frequency standard is suitable for an array of both terrestrial and space based applications. An optical atomic clock based upon a two-photon transition at 778 nm in rubidium, is an ideal candidate to meet the requirements of Global Satellite Navigation System (GNSS), while being a viable option for other applications. Here we demonstrate that a simple architecture, using off-the-shelf components and an external cavity diode laser system that is confined to less than 3 ft2 of breadboard, exhibits a frequency instability of 7 x 10-13/??, for times less than 100 seconds.

DOI
10.33012/2016.13158

Related papers

Compact Optical Clock with 5×10 −13 Instability at 1 s

Gretchen R. Phelps, N. Lemke, Christopher Erickson +2 more

We present a compact optical atomic clock design based on a two-photon transition at 778 nm in rubidium that is capable of a frequency instability of 5×10−13 at 1 s. The simple architecture occupies less than 30 L volume and currently uses commercial off-the-shelf components making this system an attractive, appealing, and competitive candidate to meet GPS-III spacecraft frequency stability requirements. Copyright © 2018 Institute of Navigation.

NAVIGATION Journal of the Institute of Navigation•Mar 1, 2018•19 citations

The optical rubidium atomic frequency standard at AFRL

N. Lemke, Gretchen R. Phelps, John H. Burke +2 more

We present a compact optical frequency standard based on two-photon spectroscopy at 778 nm in a rubidium vapor cell. We demonstrate fractional instability of 3e-13/, √τ/s for timescales up to 10,000 s. Additionally, we describe a secondary system operation in which the short-term stability is improved (though at the expense of the long-term stability) using increased laser power, resulting in 1 s instability <; 1e-13. The system has been designed as an advanced atomic frequency standard for GNSS applications, and is currently being investigated for demonstration on AFRL's Navigation Technology Satellite 3 (NTS-3), an upcoming space flight experiment to middle earth orbit scheduled for launch in 2022.

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)•Jul 1, 2017•3 citations

A Portable Dual-Color Two-Photon Rubidium Optical Frequency Standard

Sarah Scholten, Emily Ahern, Clayton R. Locke +8 more

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.

arXiv:2609.08083•Sep 8, 2026•0 citations

Compact Optical Atomic Clock Based on a Two-Photon Transition in Rubidium

Kyle W. Martin, Gretchen R. Phelps, N. Lemke +7 more

Optical frequency standards surpass their microwave counterparts in both stability and accuracy, yet they are often bulky, power-hungry, and unable to operate outside of a well-controlled laboratory environment. Leveraging a two-photon transition in ${}^{87}$Rb vapor and recent advances in fiber frequency combs, the authors build an optical clock to beat the current portable standards, with an architecture that can be made compact and low-power. These results point the way to a real-world optical frequency standard of even higher stability, for applications such as satellite navigation.

arXiv:1903.11231•Physical Review Applied•Jan 18, 2018•171 citations

High-performance, compact optical standard

Zachary L. Newman, Vincent N. Maurice, Connor D. Fredrick +6 more

We describe a high-performance, compact optical frequency standard based on a microfabricated Rb vapor cell and a low-noise, external cavity diode laser operating on the Rb two-photon transition at 778 nm. The optical standard achieves an instability of 1.8 × 10 − 13 τ − 1 / 2 for times less than 100 s and a flicker noise floor of 1 × 10 − 14 out to 6000 s. At long integration times, the instability is limited by variations in optical probe power and the ac Stark shift. The retrace was measured to 5.7 × 10 − 13 after 30 h of dormancy. Such a simple, yet high-performance optical standard could be suitable as an accurate realization of the meter or, if coupled with an optical frequency comb, as a compact atomic clock comparable to a hydrogen maser.

arXiv:2105.00610•Optics Letters•Aug 17, 2021•77 citations

Miniaturized optical frequency reference for next-generation portable optical clocks

Vincent N. Maurice, Zachary L. Newman, Susannah M. Dickerson +7 more

Optical frequency standards, or lasers stabilized to atomic or molecular transitions, are widely used in length metrology and laser ranging, provide a backbone for optical communications and lie at the heart of next-generation optical atomic clocks. Here we demonstrate a compact, low-power optical frequency reference based on the Doppler-free, two-photon transition in rubidium-87 at 778 nm implemented on a micro-optics breadboard. Our optical reference achieves a fractional frequency instability of 2.9×10−12/ τ for averaging times τ less than 103 s, has a volume of ≈35 cm3 and operates on ≈450 mW of electrical power. The advanced optical integration presented here demonstrates a key step towards the development of compact optical clocks and the broad dissemination of SI-traceable wavelength references.

arXiv:2003.13172•Optics Express•Jul 15, 2020•71 citations
Precision navigation and timing is an important focus in the Air Force Research Laboratory's experimental efforts. The development and testing of an optical frequency standard is suitable for an array of both terrestrial and space based applications. An optical atomic clock based upon a two-photon transition at 778 nm in rubidium, is an ideal candidate to meet the requirements of Global Satellite Navigation System (GNSS), while being a viable option for other applications. Here we demonstrate that a simple architecture, using off-the-shelf components and an external cavity diode laser system that is confined to less than 3 ft2 of breadboard, exhibits a frequency instability of 7 x 10-13/??, for times less than 100 seconds.
We present a compact optical frequency standard based on two-photon spectroscopy at 778 nm in a rubidium vapor cell. We demonstrate fractional instability of 3e-13/, √τ/s for timescales up to 10,000 s. Additionally, we describe a secondary system operation in which the short-term stability is improved (though at the expense of the long-term stability) using increased laser power, resulting in 1 s instability <; 1e-13. The system has been designed as an advanced atomic frequency standard for GNSS applications, and is currently being investigated for demonstration on AFRL's Navigation Technology Satellite 3 (NTS-3), an upcoming space flight experiment to middle earth orbit scheduled for launch in 2022.
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 5S1/2→5D5/25S_{1/2}\rightarrow5D_{5/2}5S1/2​→5D5/2​ two-photon transition in 87^{87}87Rb. 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 1.9×10−131.9\times10^{-13}1.9×10−13 at 1s of integration time, reaching 3.5×10−153.5\times10^{-15}3.5×10−15 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.
Optical frequency standards surpass their microwave counterparts in both stability and accuracy, yet they are often bulky, power-hungry, and unable to operate outside of a well-controlled laboratory environment. Leveraging a two-photon transition in 87{}^{87}87Rb vapor and recent advances in fiber frequency combs, the authors build an optical clock to beat the current portable standards, with an architecture that can be made compact and low-power. These results point the way to a real-world optical frequency standard of even higher stability, for applications such as satellite navigation.
We describe a high-performance, compact optical frequency standard based on a microfabricated Rb vapor cell and a low-noise, external cavity diode laser operating on the Rb two-photon transition at 778 nm. The optical standard achieves an instability of 1.8 × 10 − 13 τ − 1 / 2 for times less than 100 s and a flicker noise floor of 1 × 10 − 14 out to 6000 s. At long integration times, the instability is limited by variations in optical probe power and the ac Stark shift. The retrace was measured to 5.7 × 10 − 13 after 30 h of dormancy. Such a simple, yet high-performance optical standard could be suitable as an accurate realization of the meter or, if coupled with an optical frequency comb, as a compact atomic clock comparable to a hydrogen maser.
Optical frequency standards, or lasers stabilized to atomic or molecular transitions, are widely used in length metrology and laser ranging, provide a backbone for optical communications and lie at the heart of next-generation optical atomic clocks. Here we demonstrate a compact, low-power optical frequency reference based on the Doppler-free, two-photon transition in rubidium-87 at 778 nm implemented on a micro-optics breadboard. Our optical reference achieves a fractional frequency instability of 2.9×10−12/ τ for averaging times τ less than 103 s, has a volume of ≈35 cm3 and operates on ≈450 mW of electrical power. The advanced optical integration presented here demonstrates a key step towards the development of compact optical clocks and the broad dissemination of SI-traceable wavelength references.