An ion-neutral hybrid trap is built to study low-energy ion-atom collisions. The ion-neutral hybrid trap is combined with two spatially concentric traps: a linear Paul trap for the ionic species and a magneto-optical ...An ion-neutral hybrid trap is built to study low-energy ion-atom collisions. The ion-neutral hybrid trap is combined with two spatially concentric traps: a linear Paul trap for the ionic species and a magneto-optical trap(MOT) for the neutral species. The total ion atom collision rate coefficient k_(ia)between^(87)Rb atoms and optically dark ^(87)Rb^+ ions is measured by monitoring the reduction of the steady-state MOT atoms by sequentially introducing various mechanisms, namely photoionization and ion-atom collisions. In contrast to other experiments, a concise experimental procedure is devised to obtain the loss rates of the MOT atoms due to photoionization and ion atom collisions in one experimental cycle, and then the collision rate k_(ia) of cold ^(87)Rb atoms with ^(87)Rb^+ ions is deduced to 0.94(±0.24)× 10^(-13) m^3/s with T_i= 3770(±100) K measured by the time of fligt of the ion signal.The measurements show good agreement with the collision rate derived from the Langevin model.展开更多
We calculate the Rydberg and autoionization Rydbergspectra of antimony(Sb) from first principles by relativistic multichannel theory within the framework of multichannel quantum defect theory. Our calculation can be u...We calculate the Rydberg and autoionization Rydbergspectra of antimony(Sb) from first principles by relativistic multichannel theory within the framework of multichannel quantum defect theory. Our calculation can be used to classify and assign the atomic states described in recently reported three Rydberg series and four autoionizing states. The perturbation effects on line intensity, variation and line profile are discussed. Assignments of the perturber states and autoionizing states are presented.展开更多
We have deduced analytical solutions of an energy level diagram of the doubly driven/dressed atom for a two-level atom exposed to a strong near-resonant bichromatic laser field in a special case, i.e., the bichromatic...We have deduced analytical solutions of an energy level diagram of the doubly driven/dressed atom for a two-level atom exposed to a strong near-resonant bichromatic laser field in a special case, i.e., the bichromatic field with frequencies ω1 and ω2, and Rabi frequencies ?1 and ?2, in which the first coupling field of ?1 acts on the bare atomic levels, and then the resulting singly dressed states are driven by the second coupling field of ?2, thus resulting in the doubly dressed atom.We have measured the probe absorption spectra of a doubly driven two-level atom. The system consists of 52S1/2, F= 2 and 5~2P_(3/2), F'= 3 states of ^(87)Rb atoms in a magneto-optical trap(MOT) as well as the cooling/trapping beams and an additional coupling field. As for the spectroscopic properties of the doubly driven two-level atom, theoretical analytical solutions are in general agreement with the experimental spectrum as a whole.展开更多
The influence of an ionizing laser on the pump-probe spectra of^(87)Rb over the transition 5^(2)S_(1/2),F=2→5^(2)P_(3/2),F'=3 is experimentally studied in an operating magneto-optical trap.These spectral features...The influence of an ionizing laser on the pump-probe spectra of^(87)Rb over the transition 5^(2)S_(1/2),F=2→5^(2)P_(3/2),F'=3 is experimentally studied in an operating magneto-optical trap.These spectral features,including gain peak,a dispersion-like structure and absorption peak,become weak as the intensity of the ionizing laser increases.Moreover,the profiles of the absorption peak and gain peak vary as the ionizing laser intensity changes.Such results indicate that there is more than one component in the two features and that each component has different dependences on the number of^(87)Rb atoms.展开更多
基金Supported by Beijing Natural Science Foundation(1164016)National Natural Science Foundation of China(11604334,61227807,61575108)Tsinghua Initiative Scientific Research Program(2013THZ02-3)
基金Supported by the National Natural Science Foundation of China under Grant Nos 11604334,61227807 and 61575108the Tsinghua Initiative Scientific Research Program under Grant No 2013THZ02-3the Beijing Natural Science Foundation under Grant No 1164016
文摘An ion-neutral hybrid trap is built to study low-energy ion-atom collisions. The ion-neutral hybrid trap is combined with two spatially concentric traps: a linear Paul trap for the ionic species and a magneto-optical trap(MOT) for the neutral species. The total ion atom collision rate coefficient k_(ia)between^(87)Rb atoms and optically dark ^(87)Rb^+ ions is measured by monitoring the reduction of the steady-state MOT atoms by sequentially introducing various mechanisms, namely photoionization and ion-atom collisions. In contrast to other experiments, a concise experimental procedure is devised to obtain the loss rates of the MOT atoms due to photoionization and ion atom collisions in one experimental cycle, and then the collision rate k_(ia) of cold ^(87)Rb atoms with ^(87)Rb^+ ions is deduced to 0.94(±0.24)× 10^(-13) m^3/s with T_i= 3770(±100) K measured by the time of fligt of the ion signal.The measurements show good agreement with the collision rate derived from the Langevin model.
基金Supported by the Beijing Natural Science Foundation under Grant No 1164016the National Natural Science Foundation of China under Grant No 11604334the Funding from TRIUMF which receives Federal Funding via a Contribution Agreement with the National Research Council of Canada and through a Natural Sciences and Engineering Research Council of Canada under Grant No 386343-2011
文摘We calculate the Rydberg and autoionization Rydbergspectra of antimony(Sb) from first principles by relativistic multichannel theory within the framework of multichannel quantum defect theory. Our calculation can be used to classify and assign the atomic states described in recently reported three Rydberg series and four autoionizing states. The perturbation effects on line intensity, variation and line profile are discussed. Assignments of the perturber states and autoionizing states are presented.
基金Project supported by Beijing Natural Science Foundation,China(Grant No.1164016)the National Natural Science Foundation of China(Grant Nos.11604334,61227807,and 61575108)the Tsinghua Initiative Scientific Research Program,China(Grant No.2013THZ02-3)
文摘We have deduced analytical solutions of an energy level diagram of the doubly driven/dressed atom for a two-level atom exposed to a strong near-resonant bichromatic laser field in a special case, i.e., the bichromatic field with frequencies ω1 and ω2, and Rabi frequencies ?1 and ?2, in which the first coupling field of ?1 acts on the bare atomic levels, and then the resulting singly dressed states are driven by the second coupling field of ?2, thus resulting in the doubly dressed atom.We have measured the probe absorption spectra of a doubly driven two-level atom. The system consists of 52S1/2, F= 2 and 5~2P_(3/2), F'= 3 states of ^(87)Rb atoms in a magneto-optical trap(MOT) as well as the cooling/trapping beams and an additional coupling field. As for the spectroscopic properties of the doubly driven two-level atom, theoretical analytical solutions are in general agreement with the experimental spectrum as a whole.
基金the National Natural Science Foundation of China under Grant No 11074299Tsinghua University Initative Scientific Research Program under Grant No 20101081779.
文摘The influence of an ionizing laser on the pump-probe spectra of^(87)Rb over the transition 5^(2)S_(1/2),F=2→5^(2)P_(3/2),F'=3 is experimentally studied in an operating magneto-optical trap.These spectral features,including gain peak,a dispersion-like structure and absorption peak,become weak as the intensity of the ionizing laser increases.Moreover,the profiles of the absorption peak and gain peak vary as the ionizing laser intensity changes.Such results indicate that there is more than one component in the two features and that each component has different dependences on the number of^(87)Rb atoms.
