The modulation transfer spectroscopy in an ytterbium hollow cathode lamp at 399 nm is measured. The error signal for frequency locking is optimized by measuring the dependences of its slope, linewidth and magnitude on...The modulation transfer spectroscopy in an ytterbium hollow cathode lamp at 399 nm is measured. The error signal for frequency locking is optimized by measuring the dependences of its slope, linewidth and magnitude on various parameters. Under the optimum condition, the laser frequency at 399 nm can be stabilized. The long-term stability of laser frequency is measured by monitoring the fluorescence signal of the ytterbium atomic beam induced by the locked laser. The laser frequency is shown to be tightly locked, and the stabilized laser is successfully applied to the cooling of ytterbium atoms.展开更多
We report construction of an iodine-stabilized laser frequency standard at 532 nm based on modulation transfer spectroscopy(MTS)technology with good reproducibility.A frequency stability of 2.5×10^(-14)at 1 s ave...We report construction of an iodine-stabilized laser frequency standard at 532 nm based on modulation transfer spectroscopy(MTS)technology with good reproducibility.A frequency stability of 2.5×10^(-14)at 1 s averaging time is achieved,and the frequency reproducibility has a relative uncertainty of 3.5×10^(-13),demonstrating the great stability of our setup.The systematic uncertainty of the iodine-stabilized laser frequency standard is evaluated,especially the contribution of the residual amplitude modulation(RAM).The contribution of the RAM in MTS cannot be evaluated directly.To solve this problem,we theoretically deduce the MTS signal with RAM under large modulation depth,and prove that the non-symmetric shape of the MTS signal is directly related to the MTS effect.The non-symmetric shape factor can be calibrated with a frequency comb,and in real experiments,this value can be obtained by least-squares fitting of the MTS signal,from which we can infer the RAMinduced frequency shift.The full frequency uncertainty is evaluated to be 5.3 kHz(corresponding to a relative frequency uncertainty of 9.4×10^(-12)).The corrected transition frequency has a difference from the BIPM-recommended value of 2 kHz,which is within 1σ uncertainty,proving the validity of our evaluation.展开更多
We report laser frequency stabilization with modulation transfer spectroscopy（MTS） on 85 Rb atoms. With both PZT（piezo-electric transducer） slow-loop feedback and current fastloop feedback to the laser head, we ge...We report laser frequency stabilization with modulation transfer spectroscopy（MTS） on 85 Rb atoms. With both PZT（piezo-electric transducer） slow-loop feedback and current fastloop feedback to the laser head, we get a linewidth narrowing less than 5 kHz simultaneously. Laser injection to a laser diode and frequency beating with another polarization spectroscopy based stabilization setup are also employed to check the narrow linewidth property. With the help of the technique, a linewidth around k Hz-level laser is obtained and pave the way for the locking of the lattice laser of ytterbium clock with transfer cavity technique. The setup can be used as a frequency reference for precise frequency control of atomic clock system.展开更多
We present a modulation transfer spectroscopy（MTS） configuration based on an acousto-optic modulator by using a variant of the typical double pass structure. One beam is modulated by using an acousto-optic modulator...We present a modulation transfer spectroscopy（MTS） configuration based on an acousto-optic modulator by using a variant of the typical double pass structure. One beam is modulated by using an acousto-optic modulator in opposite diffraction order to cancel the carrier frequency shift and produce a modulated pump beam. The line shape performance is investigated theoretically and experimentally. Laser frequency stabilization of the proposed configuration is demonstrated for the133 Cs ｜62 S1/2, F = 4 → ｜62 P3/2, F = 5 transition. The Allan deviations, which are measured by using beat note signals and the three-cornered hat method, are 3.6×10-11 in an integration time of 100 s and approximately 4×10-11 in a longer integration time.展开更多
This study investigates the application of miniature quantum references within small-scale optical atomic frequency standards,utilizing a diminutive^(87)Rb glass cell,dimensions of 6 mm×6 mm×6 mm,to establis...This study investigates the application of miniature quantum references within small-scale optical atomic frequency standards,utilizing a diminutive^(87)Rb glass cell,dimensions of 6 mm×6 mm×6 mm,to establish a quantum frequency standard.'By employing the transition spectrum from 5^(2)S_(1/2)F=2 to 5^(2)P_(3/2)F=3,this study successfully demonstrates the development of a compact rubidium atomic optical frequency standard via modulation transfer spectroscopy(MTS).Subsequent to frequency stabilization,the 780 nm clock laser exhibits a linewidth of 6.9 k Hz,and its out-of-loop short-term stability reaches4.1×10^(-13)@1 s,as confirmed through beat frequency analysis.This research not only provides a practical blueprint for the development of small optical atomic frequency standards but also lays down essential groundwork for future advancements in chip-level optical frequency standard technologies.展开更多
Optical clocks with thermal atoms are characterized by compact size,simple structure,reduced weight,and low power consumption and have the potential for broad out-of-the-lab and commercial applications.Here,we demonst...Optical clocks with thermal atoms are characterized by compact size,simple structure,reduced weight,and low power consumption and have the potential for broad out-of-the-lab and commercial applications.Here,we demonstrate a 459 nm optical clock based on the 6S_(1/2)-7P_(1/2)transition in thermal^(133)Cs atoms.Two methods,modulation transfer spectroscopy(MTS)and frequency modulation spectroscopy(FMS),are employed to stabilize the frequency of a 459 nm commercial laser to the atomic transition.The MTS-MTS and MTS-FMS beat-note measurements show short-term frequency stabilities of 3.7×10^(-13)/√t and 6.4×10^(-13)/√t,respectively,at the averaging time t.The 459 nm passive optical clock further serves as the pump for an active 1470 nm optical clock based on the cavityless lasing.The resultant 1470 nm output power reaches over 10μW and the pump-beam-induced light shift is estimated to be 2π×11 Hz with a fractional uncertainty of 2.4×10^(-18).These results demonstrate the feasibility of hybridizing passive and active optical clocks,providing a promising route toward compact multi-wavelength optical frequency standards.展开更多
We report the experimental results on measuring the isotope shifts and hyperfine splittings of all ytterbium isotopes for a 399-nm transition by using a quite simple and novel method. It benefits from the advantages o...We report the experimental results on measuring the isotope shifts and hyperfine splittings of all ytterbium isotopes for a 399-nm transition by using a quite simple and novel method. It benefits from the advantages of the modulation transfer spectroscopy in an ytterbium hollow cathode lamp and the Doppler-free spectroscopy in a collimated ytterbium atomic beam. The key technique in this experiment is simultaneously measuring the frequency separations of the two spectra twice, and the separation difference between two measurements is solely determined by the well-defined frequency of an acousto-optics modulator. Compared with the most of previously reported experimental results, ours are more accurate and completed, which will provide the useful information for developing a more accurate theoretical model to describe the interaction inside an ytterbium atom.展开更多
Atomic clocks represent the most advanced instruments for providing time-frequency standards,with increasing demand for designs that offer high frequency stability while minimizing size.Central to an atomic clock'...Atomic clocks represent the most advanced instruments for providing time-frequency standards,with increasing demand for designs that offer high frequency stability while minimizing size.Central to an atomic clock's function is the atomic vapor cell,which serves as the quantum reference.Compared to traditional cells,wafer-level micro-electro-mechanical systems(MEMS)vapor cells enable cost-effective,scalable production and facilitate integration with silicon-based chips.In this work,we present a wafer-level MEMS vapor cell featuring an innovative silicon-glass-silicon transverse optical path structure.A single wafer is used to fabricate 24 identical atomic vapor cells,each with precise dimensions of 14 mm×14 mm×4.3 mm,ensuring scalability.We demonstrate an optical frequency standard that combines modulation transfer spectroscopy(MTS)with a MEMS vapor cell,featuring a compact design with excellent performance.This frequency standard achieves stability over averaging times of 1–400 s,with short-term stability of 2.6×10^(-13)at 1 s and 5.1×10^(-14)at 200 s.The laser linewidth is only 3.9 kHz,marking a substantial improvement over existing thermal standards,and opening potential applications in navigation,radar,and precision measurement.This work provides a crucial step toward the development of chip-scale optical clocks.展开更多
We demonstrate a dual-wavelength optical frequency standard based on the dual-optical-transition modulation transfer spectroscopy(DOT-MTS)between different quantum transitions of the rubidium D1(795 nm)and D2(780 nm)l...We demonstrate a dual-wavelength optical frequency standard based on the dual-optical-transition modulation transfer spectroscopy(DOT-MTS)between different quantum transitions of the rubidium D1(795 nm)and D2(780 nm)lines.In a single rubidium atomic ensemble,modulation frequency sidebands from the 780 nm pump beam are simultaneously transferred to both the 780 and 795 nm probe lasers.The DOT-MTS enables the simultaneous stabilization of 780 and 795 nm lasers on a single vapor cell.Both lasers exhibit a frequency instability in the low 10-14range at 1 s of averaging,as estimated from the residual error signal.A theoretical model is developed based on the V-type atomic level structure to illustrate the dual-wavelength spectroscopy.This approach can be extended to develop a multi-wavelength optical frequency standard within a single atomic ensemble,broadening its applicability in fields such as precision metrology,Rydberg atoms,wavelength standards,optical networks,and beyond.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.10774044)the National Key Basic Research and Development Program of China(Grant No.2010CB922903)+1 种基金the Science and Technology Commission of Shanghai Municipality of China(Grant No.07JC14019)Shanghai Pujiang Talent Program of China(Grant No.07PJ14038)
文摘The modulation transfer spectroscopy in an ytterbium hollow cathode lamp at 399 nm is measured. The error signal for frequency locking is optimized by measuring the dependences of its slope, linewidth and magnitude on various parameters. Under the optimum condition, the laser frequency at 399 nm can be stabilized. The long-term stability of laser frequency is measured by monitoring the fluorescence signal of the ytterbium atomic beam induced by the locked laser. The laser frequency is shown to be tightly locked, and the stabilized laser is successfully applied to the cooling of ytterbium atoms.
基金the National Key Research and Development Program of China(Grant No.2017YFA0304401)Key-Area Research and Development Program of GuangDong Province,China(Grant No.2019B030330001)the National Natural Science Foundation of China(Grant Nos.11174095,61875065,91536116,and 11804108).
文摘We report construction of an iodine-stabilized laser frequency standard at 532 nm based on modulation transfer spectroscopy(MTS)technology with good reproducibility.A frequency stability of 2.5×10^(-14)at 1 s averaging time is achieved,and the frequency reproducibility has a relative uncertainty of 3.5×10^(-13),demonstrating the great stability of our setup.The systematic uncertainty of the iodine-stabilized laser frequency standard is evaluated,especially the contribution of the residual amplitude modulation(RAM).The contribution of the RAM in MTS cannot be evaluated directly.To solve this problem,we theoretically deduce the MTS signal with RAM under large modulation depth,and prove that the non-symmetric shape of the MTS signal is directly related to the MTS effect.The non-symmetric shape factor can be calibrated with a frequency comb,and in real experiments,this value can be obtained by least-squares fitting of the MTS signal,from which we can infer the RAMinduced frequency shift.The full frequency uncertainty is evaluated to be 5.3 kHz(corresponding to a relative frequency uncertainty of 9.4×10^(-12)).The corrected transition frequency has a difference from the BIPM-recommended value of 2 kHz,which is within 1σ uncertainty,proving the validity of our evaluation.
基金Supported by the National Natural Science Foundation of China(61227805,11574352,91536104,91636215)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB21030700)
文摘We report laser frequency stabilization with modulation transfer spectroscopy（MTS） on 85 Rb atoms. With both PZT（piezo-electric transducer） slow-loop feedback and current fastloop feedback to the laser head, we get a linewidth narrowing less than 5 kHz simultaneously. Laser injection to a laser diode and frequency beating with another polarization spectroscopy based stabilization setup are also employed to check the narrow linewidth property. With the help of the technique, a linewidth around k Hz-level laser is obtained and pave the way for the locking of the lattice laser of ytterbium clock with transfer cavity technique. The setup can be used as a frequency reference for precise frequency control of atomic clock system.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFA0302101)the Foundation of China Academy of Space Technologythe Initiative Program of State Key Laboratory of Precision Measurement Technology and Instruments,China
文摘We present a modulation transfer spectroscopy（MTS） configuration based on an acousto-optic modulator by using a variant of the typical double pass structure. One beam is modulated by using an acousto-optic modulator in opposite diffraction order to cancel the carrier frequency shift and produce a modulated pump beam. The line shape performance is investigated theoretically and experimentally. Laser frequency stabilization of the proposed configuration is demonstrated for the133 Cs ｜62 S1/2, F = 4 → ｜62 P3/2, F = 5 transition. The Allan deviations, which are measured by using beat note signals and the three-cornered hat method, are 3.6×10-11 in an integration time of 100 s and approximately 4×10-11 in a longer integration time.
文摘This study investigates the application of miniature quantum references within small-scale optical atomic frequency standards,utilizing a diminutive^(87)Rb glass cell,dimensions of 6 mm×6 mm×6 mm,to establish a quantum frequency standard.'By employing the transition spectrum from 5^(2)S_(1/2)F=2 to 5^(2)P_(3/2)F=3,this study successfully demonstrates the development of a compact rubidium atomic optical frequency standard via modulation transfer spectroscopy(MTS).Subsequent to frequency stabilization,the 780 nm clock laser exhibits a linewidth of 6.9 k Hz,and its out-of-loop short-term stability reaches4.1×10^(-13)@1 s,as confirmed through beat frequency analysis.This research not only provides a practical blueprint for the development of small optical atomic frequency standards but also lays down essential groundwork for future advancements in chip-level optical frequency standard technologies.
基金provided by CAS Project for Young Scientists in Basic Research(Grant No.YSBR-085)National Time Service Center(Grant No.E239SC1101)+1 种基金the funding of Wenzhou Major Science&Technology Innovation Key Project(Grant No.ZG2023021)supported by Innovation Program for Quantum Science and Technology(Grant No.2021ZD0303200).
文摘Optical clocks with thermal atoms are characterized by compact size,simple structure,reduced weight,and low power consumption and have the potential for broad out-of-the-lab and commercial applications.Here,we demonstrate a 459 nm optical clock based on the 6S_(1/2)-7P_(1/2)transition in thermal^(133)Cs atoms.Two methods,modulation transfer spectroscopy(MTS)and frequency modulation spectroscopy(FMS),are employed to stabilize the frequency of a 459 nm commercial laser to the atomic transition.The MTS-MTS and MTS-FMS beat-note measurements show short-term frequency stabilities of 3.7×10^(-13)/√t and 6.4×10^(-13)/√t,respectively,at the averaging time t.The 459 nm passive optical clock further serves as the pump for an active 1470 nm optical clock based on the cavityless lasing.The resultant 1470 nm output power reaches over 10μW and the pump-beam-induced light shift is estimated to be 2π×11 Hz with a fractional uncertainty of 2.4×10^(-18).These results demonstrate the feasibility of hybridizing passive and active optical clocks,providing a promising route toward compact multi-wavelength optical frequency standards.
基金Project supported by the National Natural Science Foundation of China(Grant No.10774044)the National Key Basic Research and Development Program of China(Grant No.2010CB922903)+1 种基金the Science Foundation of the Science and Technology Commission of Shanghai Municipality of China(Grant No.07JC14019)the Shanghai Pujiang Talent Program of China(Grant No.07PJ14038)
文摘We report the experimental results on measuring the isotope shifts and hyperfine splittings of all ytterbium isotopes for a 399-nm transition by using a quite simple and novel method. It benefits from the advantages of the modulation transfer spectroscopy in an ytterbium hollow cathode lamp and the Doppler-free spectroscopy in a collimated ytterbium atomic beam. The key technique in this experiment is simultaneously measuring the frequency separations of the two spectra twice, and the separation difference between two measurements is solely determined by the well-defined frequency of an acousto-optics modulator. Compared with the most of previously reported experimental results, ours are more accurate and completed, which will provide the useful information for developing a more accurate theoretical model to describe the interaction inside an ytterbium atom.
基金Beijing Nova Program(20240484696)INNOVATION Program for Quantum Science and Technology(2021ZD0303202)+1 种基金Wenzhou Major Science and Technology Innovation Key Project(ZG2020046)National Natural Science Foundation of China(62401019)。
文摘Atomic clocks represent the most advanced instruments for providing time-frequency standards,with increasing demand for designs that offer high frequency stability while minimizing size.Central to an atomic clock's function is the atomic vapor cell,which serves as the quantum reference.Compared to traditional cells,wafer-level micro-electro-mechanical systems(MEMS)vapor cells enable cost-effective,scalable production and facilitate integration with silicon-based chips.In this work,we present a wafer-level MEMS vapor cell featuring an innovative silicon-glass-silicon transverse optical path structure.A single wafer is used to fabricate 24 identical atomic vapor cells,each with precise dimensions of 14 mm×14 mm×4.3 mm,ensuring scalability.We demonstrate an optical frequency standard that combines modulation transfer spectroscopy(MTS)with a MEMS vapor cell,featuring a compact design with excellent performance.This frequency standard achieves stability over averaging times of 1–400 s,with short-term stability of 2.6×10^(-13)at 1 s and 5.1×10^(-14)at 200 s.The laser linewidth is only 3.9 kHz,marking a substantial improvement over existing thermal standards,and opening potential applications in navigation,radar,and precision measurement.This work provides a crucial step toward the development of chip-scale optical clocks.
基金Beijing Nova Program(20240484696)Innovation Program for Quantum Science and Technology(2021ZD0303202)Wenzhou Major Science and Technology Innovation Key Project(ZG2020046)。
文摘We demonstrate a dual-wavelength optical frequency standard based on the dual-optical-transition modulation transfer spectroscopy(DOT-MTS)between different quantum transitions of the rubidium D1(795 nm)and D2(780 nm)lines.In a single rubidium atomic ensemble,modulation frequency sidebands from the 780 nm pump beam are simultaneously transferred to both the 780 and 795 nm probe lasers.The DOT-MTS enables the simultaneous stabilization of 780 and 795 nm lasers on a single vapor cell.Both lasers exhibit a frequency instability in the low 10-14range at 1 s of averaging,as estimated from the residual error signal.A theoretical model is developed based on the V-type atomic level structure to illustrate the dual-wavelength spectroscopy.This approach can be extended to develop a multi-wavelength optical frequency standard within a single atomic ensemble,broadening its applicability in fields such as precision metrology,Rydberg atoms,wavelength standards,optical networks,and beyond.
