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 demonstrate experimentally the population inversion between 7S1/2 and 6P3/2 levels of cesium in thermal cesium cell with a 455.5 nm pumping laser.We calculate the relative population probabilities at each level the...We demonstrate experimentally the population inversion between 7S1/2 and 6P3/2 levels of cesium in thermal cesium cell with a 455.5 nm pumping laser.We calculate the relative population probabilities at each level theoretically with the density matrix method.In a steady state,5.8% atoms are at 7S1/2 level and 2.9% at 6P3/2 level,which builds up the population inversion between the two levels.We obtain the fluorescence spectra produced in thermal cesium cell in our experiment.The measured relative intensity of each available fluorescence spectral line in the experiment agrees very well with the theoretical result.The demonstrated population inversion between 7S1/2 and 6P3/2 levels can be used to construct an active optical clock of four-level system with a wavelength of 1469.9 nm.展开更多
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supported by the National Natural Science Foundation of China (Grant Nos. 10874009 and 11074011)
文摘We demonstrate experimentally the population inversion between 7S1/2 and 6P3/2 levels of cesium in thermal cesium cell with a 455.5 nm pumping laser.We calculate the relative population probabilities at each level theoretically with the density matrix method.In a steady state,5.8% atoms are at 7S1/2 level and 2.9% at 6P3/2 level,which builds up the population inversion between the two levels.We obtain the fluorescence spectra produced in thermal cesium cell in our experiment.The measured relative intensity of each available fluorescence spectral line in the experiment agrees very well with the theoretical result.The demonstrated population inversion between 7S1/2 and 6P3/2 levels can be used to construct an active optical clock of four-level system with a wavelength of 1469.9 nm.
