Bulletin of the American Physical Society
41st Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 55, Number 5
Tuesday–Saturday, May 25–29, 2010; Houston, Texas
Session X4: Precision Atomic Spectroscopy |
Hide Abstracts |
Sponsoring Units: GPMFC Chair: Brett Depaola, Kansas State University Room: Regency Ballroom |
Saturday, May 29, 2010 10:30AM - 10:42AM |
X4.00001: Stabilized 2051 nm TmHo:YLF laser and applications in Barium 137 Matthew Hoffman, Adam Kleczewski, Eric Magnuson, Boris Blinov, E.N. Fortson We report on the development of a tunable frequency stabilized laser operating at a wavelength of 2051 nm and its applications in $^{137}$Ba$^{+}$. A commercially available TmHo: YLF laser was frequency doubled using a periodically poled lithium niobate crystal and then frequency shifted using a broadband acousto-optic modulator. The shifted 1025 nm beam was then sent into a reference cavity with a finesse of approximately 350,000 made of ultra-low expansion glass, and the laser frequency is stabilized using the Pound-Drever-Hall method. Using a linear Paul trap, we confine and laser cool single barium ions, and excite the 6S$_{3/2}$ to 5D$_{3/2}$ clock transition at 2051 nm. We plan to use this electric quadrupole transition as a clock transition in an optical frequency standard. This TmHo: YLF laser will also be employed to perform precision spectroscopy of the 5D$_{3/2}$ manifold which will allow us to determine the nuclear magnetic octopole moment of $^{137}$Ba. Finally, we have plans to use this laser to test atomic parity non-conservation in a single trapped $^{137}$Ba ion. [Preview Abstract] |
Saturday, May 29, 2010 10:42AM - 10:54AM |
X4.00002: Improved dipole transition strengths in Ba$^{+}$ from Ba Rydberg spectroscopy Shannon L. Woods, Stephen R. Lundeen, Erica L. Snow Recent determinations of the dipole transition strengths between the 6$^{2}$S$_{1/2}$ ground state of Ba$^{+}$ and the 6$^{2}$P$_{1/2}$ and 6$^{2}$P$_{3/2}$ levels combined two types of Rydberg Ba fine structure measurements, perturbed binding energy measurements and K-splitting measurements, to determine both transition strengths and their ratio more precisely than allowed by existing lifetime measurements [1]. The precision of these results, however, was limited not by the Rydberg measurements, but by uncertainty in the calculation of the polarizability of Ba$^{2+}$ which had not been measured directly. The recently reported measurement of this polarizability [2] allows an improved analysis of existing Rydberg data and reduces the uncertainty in the inferred transition strengths.\\[4pt] [1] Shannon L. Woods, S. R. Lundeen, and Erica L. Snow, Phys. Rev. A 80, 042516 (2009)\\[0pt] [2] Erica L. Snow, et. al. private communication. [Preview Abstract] |
Saturday, May 29, 2010 10:54AM - 11:06AM |
X4.00003: Absolute and ratio measurements of the polarizability of Na, K, and Rb with an atom interferometer William Holmgren, Melissa Revelle, Vincent Lonij, Alexander Cronin We present absolute and ratio measurements of the ground state electric dipole polarizability of sodium, potassium, and rubidium using a Mach-Zehnder atom interferometer with an electric field gradient. The uncertainty of each absolute measurement is less than 1.0\% and the uncertainty of each ratio measurement is 0.3\%. Our measurements serve as improved tests of atomic structure calculations. [Preview Abstract] |
Saturday, May 29, 2010 11:06AM - 11:18AM |
X4.00004: Specific mass shift measurements in radioactive Rb isotopes by Doppler-free two-photon transitions Tao Kong, T. Wiebe, A. Chatwin-Davies, A. Berman, A. Gorelov, M. Pearson, J. Behr, S. Behling, G. Gwinner For an exotic particle search involving the decay of laser trapped Rb nuclear isomers, the fast-moving decay daughters must be photo-ionized to measure their momentum. Doppler-free two-photon 5S$_{1/2}$ to 5D$_{5/2}$ transition is used to selectively photo-ionize the daughter isotopes. We have measured the 5D$_{5/2}$ state hyperfine structure and isotope shifts of $^{86m}$Rb, $^{86g}$Rb and $^{81g}$Rb, with accuracy between 0.1 $\sim $ 0.9 MHz. Systematic errors have been investigated offline on $^{87}$Rb under the same experimental conditions, and the dominant effect is a Zeeman shift $\sim $ 0.2 MHz. The specific mass shift difference between S$_{1/2}$ to P$_{3/2}$ transition and S$_{1/2}$ to D$_{5/2}$ transition in those isotopes is deduced by making a King Plot, which also utilized isotope shift data measured by other groups [F. Nez, Optics Communications, 1993][C. Thibault, PRC, 1981]. Tests of time changes of fine structure constant $\alpha $ need isotope shifts of alkali-like species [Berengut, PRA, 2003]. [Preview Abstract] |
Saturday, May 29, 2010 11:18AM - 11:30AM |
X4.00005: Spectroscopy of low Rydberg n$p$ states of $^{7}$Li Paul Oxley, Patrick Collins Laser-induced florescence spectroscopy of an atomic Lithium beam has been performed and the absolute energies of the n$p$ atomic states with $8\le n\le 15$ have been measured. The atoms are excited to these states by a total of four narrow bandwidth frequency-stabilized diode lasers. We review the experimental apparatus and techniques used to excite these states and present their absolute energies, which are an order of magnitude more precise than previous measurements. We compute the quantum defects of the states and compare them with recent theoretical calculations. The agreement is excellent. [Preview Abstract] |
Saturday, May 29, 2010 11:30AM - 11:42AM |
X4.00006: 2D Fourier-transform Spectroscopy of Potassium Vapor Xingcan Dai, Alan D. Bristow, Denis Karaiskaj, Steven T. Cundiff 2D Fourier-transform (2DFT) spectroscopy is a time-domain technique that measures the coherent optical response in two spectral dimensions. This method has elucidated the structure and electronic dynamics in molecules and semiconductors [1], where many-body interactions are expected. Here we demonstrate how 2DFT spectroscopy isolates specific quantum excitation pathways in a simple quantum system, namely potassium vapor in a thin transmission cell [2]. A femtosecond pulse sequence excites both the D1 and D2 lines simultaneously to reveal coupling between the transitions as a result of quantum interference and Raman-like coherences. Observations agree well with numerical simulations based on the optical Bloch equations. The non-radiative Raman pathways have population-time dependence and are isolated by altering the 2DFT projection. Density-dependent measurements show distortion of the 2DFT spectral features due to pulse propagation effects. Unexpected two-quantum coherences are observed and attributed to interatomic interactions.\\[4pt] [1] Cundiff \textit{et al}, Acc. Chem. Res. 42, 1423 (2009).\\[0pt] [2] Dai \textit{et al}, arXiv:1001.1955v1 [Preview Abstract] |
Saturday, May 29, 2010 11:42AM - 11:54AM |
X4.00007: Absolute frequency measurements of the lithium D lines using an optical frequency comb Clayton Simien, Samuel Brewer, Joseph Tan, John Gillaspy, Craig Sansonetti High precision spectroscopic measurements of the isotope shift of low-lying lithium transitions can be combined with precise theory to probe the relative nuclear charge radii of various lithium isotopes. This technique is of particular interest for exotic isotopes for which scattering experiments are not feasible. But recently measured isotope shifts for the D1 and D2 lines of the stable isotopes $^{6}$Li and $^{7}$Li remain in strong disagreement with each other and with theory. Experimental values for the splitting isotope shift (SIS), believed to be the most reliable prediction, are not even consistent as to sign and disagree with theory by as much as 16 standard deviations. We will report results from a new experiment in progress at the NIST. We observe the D lines by crossing a highly collimated lithium beam with a very stable tunable laser. Unlike previous experiments, we directly measure the optical frequency of the laser at every data point by using an optical frequency comb referenced to a cesium clock. Initial results suggest that fully resolved lithium hyperfine components will be determined with an uncertainty of a few tens of kilohertz. We expect to obtain precise new values for the fine structure, hyperfine structure, and isotope shifts of the lithium D lines and a definitive test of the calculated SIS. [Preview Abstract] |
Saturday, May 29, 2010 11:54AM - 12:06PM |
X4.00008: Precision Measurements of the J=0 to J=2 Fine-Structure Interval in the Triplet 2P State of Helium-4 Marc Smiciklas, David Shiner Our research involves measuring to high precision the fine-structure intervals in He-4 using an atomic beam apparatus and a 1083nm excitation laser with tunable sidebands. Along with a complete redesigned apparatus, many recent improvements have been implemented into our experimental setup. These include optical pumping for state preparation, electric field quenching of the singlet state, an improved metastable source for much larger signals, and an improved detector for low background. We now use different initial and final metastable states for interaction and detection over our previous technique. These changes have allowed us to greatly improve on our systematic and consistency checks, most notably, a consistency check in which we measure the hyperfine splitting in metastable He-3. Discussed will be these recently completed improvements, along with our current results. [Preview Abstract] |
Saturday, May 29, 2010 12:06PM - 12:18PM |
X4.00009: The Asymptotic Expansion Method as a Test of Large-Scale CI Calculations for Helium Rida El-Wazni, Gordon W.F. Drake The asymptotic expansion (AE) method based on a core polarization potential for the Rydberg electron continues to be of interest as a test of other computational methods because of the exceptionally high accuracy that the AE method yields for states of high angular momentum. The method itself is well established from earlier work by R. Drachman and by G. Drake [1]. In the present work, we extend that tabulated results for the Rydberg states of helium up to $L = 15$. A comparison with recent large-scale configuration interaction calculations for the nonrelativistic energies reveals that there are serious disagreements unless one takes care in the CI calculation to include all the possible angular momentum couplings that contribute [2]. The results will be extended to include a complete set of relativistic and QED corrections to give final energies that are essentially exact for all practical purposes.\\[4pt] [1] G.W.F. Drake and Z.-C. Yan, Phys.\ Rev.\ A {\bf 46}, 2378 (1992).\newline [2] R. El-Wazni and G.W.F. Drake, Phys.\ Rev.\ A {\bf 80}, 064501 (2009). [Preview Abstract] |
Saturday, May 29, 2010 12:18PM - 12:30PM |
X4.00010: Development of a configuration-interaction plus all-order method for atomic calculations Marianna Safronova, M.G. Kozlov, Dansha Jiang We developed a theoretical method within the framework of relativistic many-body theory to accurately treat correlation corrections in atoms with few valence electrons. This method combines the all-order approach currently used in precision calculations of properties of monovalent atoms with the configuration-interaction approach that is applicable for many-electron systems. This approach has been tested on the calculation of energy levels of divalent systems from Mg to Hg. We have demonstrated an improvement of at least a factor of 3 in agreement with experimental values for the two-electron binding energies and most excited-state energies in comparison with the CI+MBPT (many-body perturbation theory) method [1]. In the present work, we have extended CI+all-order method to the calculation of the transition properties and polarizabilities of divalent systems. Results are reported for the blackbody radiation shifts and magic wavelengths of divalent systems that are of interest to atomic clock development. \\[4pt] [1] M. S. Safronova, M. G. Kozlov, W. R. Johnson, and Dansha Jiang, Phys. Rev. A 80, 012516 (2009) [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700