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

arXiv:2310.10175 · Optics Express

Dual-interrogation method for suppressing light shift in Rb 778 nm two-photon transition optical frequency standard

Dou Li, Kangqi Liu, Pengfei Wang, Songbai Kang

Published Jan 2, 2024• 10 citations
arXivHTMLPDF

Abstract

two-photon transition optical frequency standard (2hν-OFS). The approach used an auxiliary system to calibrate the light shift of the primary system in real time to mitigate the absolute light shift and suppress the sensitivity of the system to the light power. Results show that after using the DI method, the absolute light shift and light-power sensitivity of the system were reduced by a factor of 10. The proposed method will improve the accuracy of the Rb 778 nm 2hν-OFS and increase the mid- and long-term stability. The method can also be applied to other vapor-cell atomic frequency standards that experience light shifts.

DOI
10.1364/oe.512205

Related papers

Suppressing the light shift in a two-photon rubidium optical frequency reference

Yorick Andeweg, John E. Kitching, Matthew T. Hummon

The two-photon transition in rubidium is an attractive candidate for use in the next generation of field-deployable atomic clocks and frequency references. However, this transition is known to suffer from a large AC Stark shift, through which fluctuations in the intensity of the interrogation laser cause fluctuations of the clock frequency, often limiting long-term stability. We implement an interrogation protocol known as the auto-compensated shift (ACS) in a two-photon rubidium optical frequency reference, reducing its sensitivity to optical intensity fluctuations by a factor of 1000. ACS alleviates the tradeoff between short-term and long-term stability imposed by the light shift and enables us to simultaneously achieve a fractional instability of 3 x 10^-14 at an integration time of 1 s and 2 x 10^-14 at an integration time of 10,000 s. We also examine a stability limit imposed on clocks using ACS by frequency noise on the laser.

Optical and Quantum Sensing and Precision Metrology II•Mar 5, 2026•0 citations

A frequency shift compensation method for light shift and vapor-cell temperature shift in atomic clocks

Dou Li, Kangqi Liu, Linzhen Zhao +1 more

Light shift and vapor-cell temperature shift are the two most significant factors dominating the long-term instability of compact atomic clocks. Due to the different physical mechanisms, there is not yet a solution that can effectively suppress the frequency shifts induced by these two effects. Here, we propose a 'resonance-offset' locking approach that compensates for the two physical frequency shifts. In this approach, the additional offset locking shift can effectively counteract the atomic resonance shifts arising from changes in vapor-cell temperature and light power, reducing the net impact on the clock's frequency to nearly zero. We have demonstrated this strategy on the 778 nm Rubidium two-photon optical frequency standard, successfully compensating for light shift and cell-temperature shift, respectively. This general method is particularly appealing for compact vapor-cell microwave and optical atomic clocks designed for the excellent stability rather than accuracy.

arXiv:2405.14281•May 23, 2024•0 citations

Light shift mitigation for the 5S-5D two-photon transition in rubidium

Roman Blum, Stefan Kundermann, Thibaud Ruelle +2 more

The rubidium two-photon optical atomic clock is a promising technology for applications that require a compact yet stable timekeeping device. However, its long-term frequency stability is often limited by the light shift (or AC Stark effect). In a rubidium two-photon frequency standard, we demonstrate in experiment that the light shift of the 778.1 nm wavelength probe beam can be mitigated with another, 1556.2 nm wavelength beam.

SPIE Quantum Technologies•Apr 5, 2024•0 citations

Beam geometry and temperature effects on the frequency stability of a 8 7 Rb two-photon optical frequency standard

Jiongyang Zhang, Yuhua Xiao, Ji Wang +8 more

Abstract High-precision time–frequency standards play vital roles in fundamental physics, geodesy, navigation, and communication. This paper reports experimental progress on an optical frequency standard (OFS) based on the 5S 1/2 → 5D 5/2 two-photon transition in 87 Rb. A 1556 nm communication-band laser is frequency-doubled to generate a 778.1 nm clock laser, which excites Rb atoms via counter-propagating beams. The 420 nm fluorescence is collected to obtain a high signal-to-noise-ratio transition spectrum. The effects of laser power and vapor cell temperature on the fluorescence intensity were systematically investigated. The impact of laser beam waist and atomic collisions on frequency shifts was analyzed. Results show that replacing a tightly focused beam with a large collimated one reduced the laser power-induced frequency shift by two orders of magnitude. Furthermore, increasing the vapor temperature enhances collision-induced frequency shifts, adversely affecting long-term stability. Under optimized conditions, the system achieved a short-term fractional frequency stability of 2.6 × 10 −13 at 1 s, reaching 5.3 × 10 −15 at 10 000 s. This work lays a critical technical foundation for the development of compact and high-performance OFSs.

Journal of Physics B Atomic Molecular and Optical Physics•May 5, 2026•1 citation

Simple method of light-shift suppression in optical pumping systems

B. H. McGuyer, Yuan‐Yu Jau, W. Happer

We report a simple method to suppress the light shift in optical pumping systems. This method uses only frequency modulation of a radio frequency or microwave source, which is used to excite an atomic resonance, to simultaneously lock the source frequency to the atomic resonance and lock the pumping light frequency to suppress the light shift. We experimentally validate the method in a vapor-cell atomic clock and verify the results through numerical simulation. This technique can be applied to many optical pumping systems that experience light shifts. It is especially useful for atomic frequency standards because it improves long-term performance, reduces the influence of the laser, and requires less equipment than previous methods.

arXiv:1302.4160•Applied Physics Letters•Jun 22, 2009•56 citations

Compact frequency standard at 1556 nm based on the two-photon transition in rubidium at 778 nm

Michel Poulin, Christine Latrasse, Driss Touahri +2 more

This is a progress report on the realization of a compact and transportable frequency standard at 1556 nm based on a two-photon transition in rubidium at 778 nm. These hyperfine transitions present great metrological interest. They have a narrow theoretical linewidth of 150 kHz when observed with a 1556 nm laser, and their absolute frequency is known with an uncertainty of 5.2 X 10-12. In this experiment, we use a high power 1556 nm DFB laser and reduce its linewidth to the 10 kHz level using optical feedback from a confocal cavity. We generate its second harmonic in a periodically poled LiNbO3 crystal and use this signal to injection-lock a Fabry-Perot laser emitting 42 mW at 778 nm. The slave laser is used to observe the Doppler-free two- photon transitions: two counter-propagating beams excite rubidium atoms which emit a blue fluorescence on resonance. This 420 nm light is detected on the side of the Rb cell with a photomultiplier. Such an optical frequency standard at 1556 nm, standing in the multiwavelength telecommunications systems window, becomes an attractive source for absolute frequency calibration of WDM components, optical spectrum analyzers and wavemeters.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Oct 8, 1998•0 citations
two-photon transition optical frequency standard (2hν-OFS). The approach used an auxiliary system to calibrate the light shift of the primary system in real time to mitigate the absolute light shift and suppress the sensitivity of the system to the light power. Results show that after using the DI method, the absolute light shift and light-power sensitivity of the system were reduced by a factor of 10. The proposed method will improve the accuracy of the Rb 778 nm 2hν-OFS and increase the mid- and long-term stability. The method can also be applied to other vapor-cell atomic frequency standards that experience light shifts.
The two-photon transition in rubidium is an attractive candidate for use in the next generation of field-deployable atomic clocks and frequency references. However, this transition is known to suffer from a large AC Stark shift, through which fluctuations in the intensity of the interrogation laser cause fluctuations of the clock frequency, often limiting long-term stability. We implement an interrogation protocol known as the auto-compensated shift (ACS) in a two-photon rubidium optical frequency reference, reducing its sensitivity to optical intensity fluctuations by a factor of 1000. ACS alleviates the tradeoff between short-term and long-term stability imposed by the light shift and enables us to simultaneously achieve a fractional instability of 3 x 10^-14 at an integration time of 1 s and 2 x 10^-14 at an integration time of 10,000 s. We also examine a stability limit imposed on clocks using ACS by frequency noise on the laser.
Light shift and vapor-cell temperature shift are the two most significant factors dominating the long-term instability of compact atomic clocks. Due to the different physical mechanisms, there is not yet a solution that can effectively suppress the frequency shifts induced by these two effects. Here, we propose a 'resonance-offset' locking approach that compensates for the two physical frequency shifts. In this approach, the additional offset locking shift can effectively counteract the atomic resonance shifts arising from changes in vapor-cell temperature and light power, reducing the net impact on the clock's frequency to nearly zero. We have demonstrated this strategy on the 778 nm Rubidium two-photon optical frequency standard, successfully compensating for light shift and cell-temperature shift, respectively. This general method is particularly appealing for compact vapor-cell microwave and optical atomic clocks designed for the excellent stability rather than accuracy.
Abstract High-precision time–frequency standards play vital roles in fundamental physics, geodesy, navigation, and communication. This paper reports experimental progress on an optical frequency standard (OFS) based on the 5S 1/2 → 5D 5/2 two-photon transition in 87 Rb. A 1556 nm communication-band laser is frequency-doubled to generate a 778.1 nm clock laser, which excites Rb atoms via counter-propagating beams. The 420 nm fluorescence is collected to obtain a high signal-to-noise-ratio transition spectrum. The effects of laser power and vapor cell temperature on the fluorescence intensity were systematically investigated. The impact of laser beam waist and atomic collisions on frequency shifts was analyzed. Results show that replacing a tightly focused beam with a large collimated one reduced the laser power-induced frequency shift by two orders of magnitude. Furthermore, increasing the vapor temperature enhances collision-induced frequency shifts, adversely affecting long-term stability. Under optimized conditions, the system achieved a short-term fractional frequency stability of 2.6 × 10 −13 at 1 s, reaching 5.3 × 10 −15 at 10 000 s. This work lays a critical technical foundation for the development of compact and high-performance OFSs.
We report a simple method to suppress the light shift in optical pumping systems. This method uses only frequency modulation of a radio frequency or microwave source, which is used to excite an atomic resonance, to simultaneously lock the source frequency to the atomic resonance and lock the pumping light frequency to suppress the light shift. We experimentally validate the method in a vapor-cell atomic clock and verify the results through numerical simulation. This technique can be applied to many optical pumping systems that experience light shifts. It is especially useful for atomic frequency standards because it improves long-term performance, reduces the influence of the laser, and requires less equipment than previous methods.
This is a progress report on the realization of a compact and transportable frequency standard at 1556 nm based on a two-photon transition in rubidium at 778 nm. These hyperfine transitions present great metrological interest. They have a narrow theoretical linewidth of 150 kHz when observed with a 1556 nm laser, and their absolute frequency is known with an uncertainty of 5.2 X 10-12. In this experiment, we use a high power 1556 nm DFB laser and reduce its linewidth to the 10 kHz level using optical feedback from a confocal cavity. We generate its second harmonic in a periodically poled LiNbO3 crystal and use this signal to injection-lock a Fabry-Perot laser emitting 42 mW at 778 nm. The slave laser is used to observe the Doppler-free two- photon transitions: two counter-propagating beams excite rubidium atoms which emit a blue fluorescence on resonance. This 420 nm light is detected on the side of the Rb cell with a photomultiplier. Such an optical frequency standard at 1556 nm, standing in the multiwavelength telecommunications systems window, becomes an attractive source for absolute frequency calibration of WDM components, optical spectrum analyzers and wavemeters.