Bulletin of the American Physical Society
2006 37th Meeting of the Division of Atomic, Molecular and Optical Physics
Tuesday–Saturday, May 16–20, 2006; Knoxville, TN
Session T6: New Experimental Techniques |
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Chair: Yuan-Yu Jau, Princeton University Room: Knoxville Convention Center 301C |
Friday, May 19, 2006 10:30AM - 10:42AM |
T6.00001: Multiply-Charged Positive Ion Polarizabilities from Rydberg Ion Fine Structure Stephen R. Lundeen, Laura E. Wright, Erica L. Snow Experimental methods originally developed for study of fine structure patterns in high-L Rydberg states of neutral atoms and molecules have recently been extended to allow study of similar states in Rydberg states of multiply-charged ions[1]. Initial studies, carried out in Rydberg states of Si$^{+}$ and Si$^{2+}$, led to determination of the polarizabilities of Na-like and Mg-like Silicon ions [2,3], but similar studies may be feasible in a wide range of systems. Continued studies are aimed at studying ions with higher charge, such as the closed shell ion Kr$^{6+}$, and eventually the Radon-like ions U$^{6+}$ and Th$^{4+}$. [1] S.R. Lundeen in \textit{Advances in Atomic, Molecular and Optical Physics, Vol. 52}, edited by P.R. Berman and C.C. Lin, p. 161 [2] R.A. Komara, M.A. Gearba, S.R. Lundeen, C.W. Fehrenbach, Phys. Rev. A 67, 062502 (2003) [3] R.A. Komara, M.A. Gearba, C.W. Fehrenbach, and S.R. Lundeen, J. Phys. B, At. Mol. Opt. Phys. 28, 2787 (2005) [Preview Abstract] |
Friday, May 19, 2006 10:42AM - 10:54AM |
T6.00002: Progress in High-Field Optical Pumping of Alkali Metal Nuclei B. Patton, K. Ishikawa, Y.-Y. Jau, W. Happer We present preliminary results of an attempt to polarize alkali metal nuclei via optical pumping in a large (9.4-tesla) magnetic field. NMR measurements of $^{87}$Rb and $^{133}$Cs films in optical cells will be reported. Depopulation pumping of alkalis can easily produce electron polarizations of order unity, as measured during spin-exchange optical pumping of noble gases [1]. At low magnetic fields ($< \sim$1 kG), the strong hyperfine coupling between the alkali electron and nucleus allows angular momentum exchange from one to the other, resulting in nuclear polarization enhancement through optical pumping. In the high magnetic fields required for NMR, however, this interaction is largely decoupled and electron-nuclear spin exchange must rely upon the $\delta A \textbf{I} \cdot \textbf{S}$ interaction induced by buffer gas collisions (also called the ``Carver rate''). High-field optical pumping experiments may allow for a more precise measurement of this rate, as well as yielding insight into the transfer of angular momentum from the polarized alkali vapor to the bulk alkali metal on the cell walls. The technical challenges of high-resolution NMR of alkali metals at 9.4 tesla will be discussed. \newline \textbf{1}. E. Babcock, I. Nelson, S. Kadlecek, et al., Physical Review Letters \textbf{91}, 123003 (2003). [Preview Abstract] |
Friday, May 19, 2006 10:54AM - 11:06AM |
T6.00003: NMR studies of Phase Transitions in Alkali Metal Films on Glass Substrates K. Ishikawa, B. Patton, Y.-Y. Jau, W. Happer We report NMR spectra of thin $^{87}$Rb films on glass in an investigation of the ``curing'' process which is commonly observed in alkali cells. The cells were cycled in temperature over a range of 5 C to 170 C and the rubidium solid-liquid phase transition was studied. The spectra of these two phases are resolvable at 9.4 T because of their different Knight shifts. Hysteresis in the observed phases confirmed reports of a curing phenomenon, and after time a supercooled liquid Rb peak could be detected at temperatures far below the predicted freezing point of 39 C. Moreover, a third NMR peak was observed at temperatures below the melting point whose frequency varied with temperature and spanned the solid and liquid frequency ranges. To our knowledge, this is the first study to characterize this additional resonance. We have also performed analogous measurements on $^{133}$Cs films. [Preview Abstract] |
Friday, May 19, 2006 11:06AM - 11:18AM |
T6.00004: Optical Transfer Cavity Stabilization using Tunable Sidebands of RF Current-Modulated Injection-Locked Diode Lasers. Parisa Bohlouli-Zanjani, James D.D. Martin It is demonstrated that RF current modulation of a frequency stabilized injection-locked diode laser allows the stabilization of an optical cavity to adjustable lengths, by variation of the RF frequency. This transfer cavity may be used to stabilize another laser at an arbitrary wavelength, in the absence of atomic or molecular transitions suitable for stabilization. Implementation involves equipment and techniques commonly used in laser cooling and trapping laboratories, and does not require electro- or acousto-optic modulators. Using this technique, we stabilize a transfer cavity using a RF current modulated diode laser, which is injection locked to a 780 nm reference diode laser. The reference laser is stabilized using saturated absorption in a Rb cell. A Ti:sapphire laser at 960 nm is then locked to this transfer cavity and may be precisely scanned by varying the RF modulation frequency. We demonstrate the suitability of this system for the excitation of laser cooled Rb atoms to Rydberg states. [Preview Abstract] |
Friday, May 19, 2006 11:18AM - 11:30AM |
T6.00005: Engineered Light Fields Designed to Manipulate Cold Atoms Matthew Pasienski, Hong Gao, Matthew White, Brian DeMarco We report experimental progress toward using spatial light modulator (SLM) technology to optically trap atoms and to coherently manipulate atomic hyperfine states. An SLM can be used to create arbitrary intensity patterns from a focused gaussian laser beam by imprinting a spatially varying phase (or ``kinoform") on the beam. We will discuss the development and implementation of computer algorithms to design kinoforms for controlling the intensity of light in two and three dimensions. Comparison between predicted and measured intensity patterns will be described. [Preview Abstract] |
Friday, May 19, 2006 11:30AM - 11:42AM |
T6.00006: Autler Townes Effect as a Probe of Molecular Electronic Transition Dipole Moments Ergin Ahmed, Peng Qi, Omer Salihoglu, Bediha Beser, Svetlana Kotochigova, Marjatta Lyyra We present a fundamentally new approach for measuring the transition dipole moment of molecular transitions, footnote{E. Ahmed et al., J. Chem. Phys. 2006 (in press).} which combines the benefits of quantum interference effects, such as the Autler-Townes (AT) splitting, with the familiar R-centroid approximation. This method is superior to other experimental methods for determining the absolute value of the R-dependent electronic transition dipole moment function, since it requires only an accurate measurement of the coupling laser electric field amplitude and the determination of the Rabi frequency from an Autler Townes split fluorescence spectral line. Using this cw triple resonance excitation technique the internuclear distance dependence of the transition moment function can be determined at several very different values of the R-centroid. The transition dipole moments of the A - X of Sodium and Lithium dimers will be illustrated for demonstration purposes. Results will be compared with ab initio calculations. [Preview Abstract] |
Friday, May 19, 2006 11:42AM - 11:54AM |
T6.00007: Buffer gas loading and Doppler cooling of strontium ions in a planar Paul trap Robert Clark, Kenneth Brown, Jaroslaw Labaziewicz, Philip Richerme, Isaac Chuang Traditional geometries for ion traps involve three dimensional structures which may be difficult to assemble in complex geometries demanded by applications such as large-scale quantum computation. Planar Paul traps provide an alternative approach [Chiaverini et. al., Quant. Inf. Comput. 5, 419 (2005)], in which the RF and DC electrodes are placed in a single plane, providing simpler fabrication and greater optical access to the trapped ions. We have designed and constructed a planar Paul trap using copper electrodes on a Rogers 4350 substrate. Strontium ions were loaded into this structure at UHV, and also at high vacuum using helium buffer gas cooling. The temperature of the ion cloud as a function of buffer gas pressure is compared to predictions from a model which includes ion-helium collisions and RF heating. The measured trap parameters, including secular frequencies, trap depth, and RF heating rates, agree well with a pseudopotential model based on finite-element electrostatic calculations. [Preview Abstract] |
Friday, May 19, 2006 11:54AM - 12:06PM |
T6.00008: Evanescent wave magnetometer Z. Wu, K. Zhao We describe a new type of atomic magnetometer, the evanescent wave magnetometer, which uses evanescent wave to measure the Larmor frequency of Rb atoms within a distance $\sim 10^{-5}\rm \, cm$ from the cell surface. The evanescent wave magnetometer has an extraordinarily small measurement volume of alkali metal vapor, which in our experiment is $5\times 10^{-7}\,\rm cm^3$. It is less susceptible to field inhomogeneities than conventional atomic magnetometers, and consequently suited for measuring or mapping fields with a large spatial gradient. Under our experimental conditions the minimum detectable magnetic field change is 0.4 nT. The sensitivity of the evanescent wave magnetometer is $20\,\rm pT\, Hz^{-1/2}$ between 0.5 and 50 Hz. Its spin shot-noise limited sensitivity is estimated to be $\rm 1.8\,pT\,Hz^{-1/2}$ for a measurement time of 1 second when the spin coherence time is limited by spin exchange collisions. [Preview Abstract] |
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