Dissertations / Theses on the topic 'Rubidium'
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1
Thompson, Sarah Theresa. "Rubidium-85 Feshbach molecules." Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3219200.
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Trachy, Marc Lawrence. "Photoassociative ionization in cold rubidium." Diss., Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/695.
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Schultz, Eric M. "Quantum interference spectroscopy with rubidium." Kansas State University, 2010. http://hdl.handle.net/2097/4614.
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Master of ScienceDepartment of Physics
Brett D. DePaola
A recent powerful spectroscopic technique that has been implemented using femtosecond lasers excites atoms or molecules through quantum interference effects. The results are oscillations in excited state populations that represent the optical frequencies used in the excitation pathway, these frequencies can be found by Fourier analysis. The technique uses a Mach-Zender interferometer wherein one femtosecond pulse is split into two pulses that are phase coherent. These pulses are the pump and probe pulses which are delayed with respect to one another by a variable time. During the delay between pulses the state excited by the first (pump) pulse evolves in time before the probe pulse is used to excite the atom into its final state. The observed final state population exhibits interference between the several possible pathways to the final state. The information gained from this method will allow for advances in other processes such as the dynamics of photo-association.
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Dewey, Wayne. "A GPS Disciplined Rubidium Clock." International Foundation for Telemetering, 1989. http://hdl.handle.net/10150/614469.
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International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, CaliforniaSub-Microsecond timing accuracy for event tagging and multisite synchronization is possible using the Global Positioning System. In order to maintain a high degree of accuracy during periods when no satellites are visible, a highly stable local time base is required. For those cases which require Cesium Oscillator stability, initial cost and continuing maintenance of the Cesium Oscillator must be considered. A viable alternative is attained by using the Global Positioning System and an oscillator disciplining process. With this system, near Cesium performance can be achieved using a more rugged lower cost Rubidium oscillator. Additionally, when 24 hour satellite coverage becomes available, system performance may surpass that of a Cesium in long term stability as well as long term drift. This presentation describes the system components, including Global Positioning System receiver, Miniaturized Controllable Rubidium Oscillator and Global Positioning System Clock. Clock timing accuracy and short and long term frequency stability results are discussed along with the control algorithms used in the disciplining process. A brief discussion of the computer modeling tools used is also presented.
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Himsworth, Matthew. "Coherent manipulation of ultracold Rubidium." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/72369/.
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The production of dense samples of atoms whose translational velocity can be parameterized by temperatures in the microkelvin range has revolutionized the fields of spectroscopy, metrology, quantum computing and sensitive tests of quantum mechanics. Such ultracold temperatures may be reached by Doppler cooling which uses a velocitysensitive scattering force. This technique relies upon atoms which have closed electronic transitions between two states so that the atoms may continuously absorb photon momenta and do not spontaneous decay into a dark state. Very few atoms fulfil this condition and attempts to cool molecules are inhibited by their extra degrees of freedom, via rotation and vibration, which add manifolds of extra states. This thesis describes the early experimental stages of investigation into coherent laseratom interactions which may be used as a general all-optical method to impart momentum to atoms and molecules and thus manipulate their velocity. The thesis covers the construction and operation of stable diode lasers, a magneto-optical trap to produce cold samples of the test species Rubidium and a high-power, phase and intensity, controllable laser to induce Raman transitions. Studies into the spectroscopy of Rubidium and the nature of coherent Raman interactions in multilevel atoms is also covered. Experimental results shows that coherent Raman transitions between the 5S1/2 ground states has been achieved in the form of sinc-squared lineshapes and Rabi-flopping.
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Sinclair, Gary F. "Cross-phase modulation in rubidium-87." Thesis, St Andrews, 2009. http://hdl.handle.net/10023/735.
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Saers, Robert. "Ultracold rubidium atoms in periodic potentials." Doctoral thesis, Umeå universitet, Fysik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1821.
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This thesis includes both experimental and theoretical investigations, presented in a series of eight papers. The experimental part ranges from the construction procedures of an apparatus for Bose-Einstein condensates, to full scale experiments using three different set-ups for ultracold atoms in optical lattices. As one of the main themes of the thesis, an experimental apparatus for production of Bose-Einstein Condensates is under construction. A magneto-optically trapped sample, hosting more than 200 million 87Rb atoms, have successfully been loaded into a magnetic trap with high transfer rate. The lifetime of the sample in the magnetic trap is in the range of 9 s, and the atoms have been shown to respond to evaporative cooling. The experiment is ready for optimization of the magnetic trap loading, and evaporative cooling parameters, which are the final steps for reaching Bose-Einstein condensation. The set-up is designed to host experiments including variable geometry optical lattices, and includes the possibility to align laser beams with high angular precision for this purpose. The breakdown of Bloch waves in a Bose-Einstein condensate is studied, attributed to the effect of energetic and dynamical instability. This experimental study is performed using a Bose-Einstein condensate in a moving one-dimensional optical lattice at LENS, Florence Italy. The optical lattice parameters, and the thermal distribution of the atomic sample required to trigger the instabilities, are detected, and compared with a theoretical model developed in parallel with the experiments. In close connection with these one-dimensional lattice studies, an experimental survey to characterize regimes of superradiant Rayleigh scattering and Bragg scattering is presented. Tunneling properties of repulsively bound atom pairs in double well potentials are characterized in an experiment at Johannes Gutenberg University, Mainz Germany. A three-dimensional optical lattice, producing an array of double wells with tunable properties is let to interact with a Bose-Einstein condensate. Pairs of ultracold atoms are produced on one side in the double wells, and their tunneling behavior, dependent on potential barrier and repulsion properties, is studied. A theoretical study of the crossover between one- and two-dimensional systems has been performed. The simulations were made for a two-dimensional array of atoms, where the behavior for different tunneling probabilities and atom-atom repulsion strengths was studied. Scaling relations for systems of variable sizes have been examined in detail, and numerical values for the involved variables have been found.
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Scotto, Stefano. "Rubidium vapors in high magnetic fields." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30318/document.
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La spectroscopie optique des atomes simples permet une mesure très précise des propriétés atomiques et des perturbations extérieures, comme par exemple des champs électriques ou magnétiques appliqués. Le spectre Zeeman correspond à une signature du champ magnétique. Dans cette thèse nous présentons l'étude de la réponse du rubidium aux champs magnétiques intenses, dans le but d'utiliser celle-ci comme une sonde de champ magnétique dans l'intervalle de 0.1 T à 60 T. Ce travail a été réalisé dans le cadre du projet RUHMA (RUbidium Atoms in High MAgnetic fields). Notre étude ouvre la voie à la métrologie optique des champs intenses, en déterminant un champ magnétique grâce à la mesure d'une fréquence optique. Le principe de l'expérience consiste à comparer les spectres atomiques expérimentaux et les spectres théoriques calculés, afin d'obtenir la valeur de l'intensité du champ. Nous avons réalisé des premiers tests en champ magnétiques statiques, compris entre 0.06 T et 0.2 T. Dans ce régime, nous avons étudié en détails les effets dus à la structure particulière des niveaux d'énergie du système atomique: des configurations à trois ou quatre niveaux produisent des nouvelles résonances et influencent l'amplitude des signaux observés . Après cette phase préliminaire, le régime de champs intenses (entre 1 T et 60 T) a été exploré, en utilisant les bobines pulsées du Laboratoire National des Champs Magnétiques Intenses de Toulouse. L'une des tâches critiques de ce travail a été la miniaturisation du système expérimental, dans le but de satisfaire les contraintes imposées par une expérience en champ intense. Avec ce système nous avons pu étudier la métrologie des champs pulsés jusqu'à environ 58 T , ce qui est, à ce jour, le champ le plus intense auquel un gaz atomique n'a jamais été soumis. L'incertitude relative de notre méthode est de l'ordre de 10-4Optical spectroscopy of simple atoms allows a very precise measurement of the atomic properties and of the external perturbations, as applied magnetic or electric fields. The Zeeman spectrum represents a magnetic field fingerprint. In this work we present our investigations about rubidium response to high magnetic fields in order to use it as magnetic field probe in the range 0.1 T - 60 T. This work was carried out in the framework of the RUHMA (RUbidium Atoms in High MAgnetic fields) project. Our investigation opens the path to magnetic field optical metrology, converting a magnetic field measurement into an optical frequency determination. The principle of the experiment is to compare experimental atomic spectra with computed theoretical spectra, in order to extract the value of the magnetic field strength. We performed our preliminary tests in static magnetic fields, ranging from 0.06 T to 0.2 T. In this framework we investigated in details some complex spectroscopic structures due to the multi-level nature of the atomic system. After this preliminary phase, the 1T-60T range have been investigated using the pulsed magnets of the Laboratoire National des Champs Magnétiques Intenses in Toulouse. We carried out an effort of miniaturization of the experimental setup in order to satisfy the constraints imposed by high magnetic field experiments. We performed metrology of pulsed magnetic field up to 58 T, which is the highest field an atomic gas has never been exposed. The accuracy of our method attained the level of 10-4
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Majeed, Hawri Omer. "Rubidium Rydberg Spectroscopy for the Micromaser." Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515550.
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Martay, Hugo E. L. "Coherent control of cold rubidium dimers." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.533833.
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Schommers, W. [Verfasser]. "Molekulardynamische Rechnungen fuer Rubidium / W. Schommers." Karlsruhe : KIT-Bibliothek, 2009. http://d-nb.info/1186904860/34.
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Brown, David Ross S. B. Massachusetts Institute of Technology. "Trapping cold rubidium in a fiber." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40908.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2007.Includes bibliographical references (p. 79-80).
In this thesis, we demonstrate the novel technique of loading cold ⁸⁷Rb into a red-detuned optical dipole trap within a hollow core photonic fiber. This confines the atoms to 6 microns in two dimensions. We initially cooled the Rubidium in a magneto-optical trap. The great confinement of the Rubidium allows for increased optical depths per atom and therefore increased interaction rates with probing light.
by David Ross Brown.
S.B.
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Hill, Cameron Louis. "Rubidium Packaging for On-Chip Spectroscopy." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5697.
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This thesis presents rubidium packaging methods for integration using anti-resonant reflecting optical waveguides (ARROWs) on a planar chip. The atomic vapor ARROW confines light through rubidium vapor, increases the light-vapor interaction length, decreases the size of the atomic cell to chip scales, and opens up possibilities for waveguide systems on chips for additional optoelectronic devices. Rubidium vapor packaging for long-life times are essential for realizing feasibly useful devices. Considerations of outgassing, leaking and chemical compatibilities of materials in rubidium vapor cells lead to an all-metal design. The effect of these characteristics on the rubidium D2 line spectra is considered.
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GOZZELINO, MICHELE. "Pulsed rubidium clock towards space applications." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2836782.
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Brandt, Lukas. "Trapping of rubidium atoms using optical tweezers." Thesis, University of Oxford, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558210.
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This thesis describes the realisation of a novel dipole force trapping method for cold neutral atoms, the optical tweezers. They are formed by imaging a spatial light modulator onto a mirror surface, by an aspherical lens. The spatial light modulator, a digital mirror device, consists of an array 1024 by 768 of micro-mirrors, which can individually be switched between the on and off position with a full frame refresh rate of 4 kHz and hence can create arbitrary light patterns in real time. Atoms are trapped through the dipole force in them. The optical tweezers have a potential depth on the order of 1 mK. A magneto-optical surface-trap cools and traps Rubidium atoms close to the mirror surface. Unlike a normal magneto-optical trap, which traps atoms in free space, this trap incorporates a mirror, above which the atoms are trapped and then loaded into the optical tweezers. I will show that we managed to load atoms into the dipole traps with a variety of different potential landscapes and observe them with a highly sensitive CCD-camera through fluorescence imaging. . . Furthermore I study a scheme to use a high powered, but spatial multimode diode laser for atom trapping. An optical diffuser smoothes out the otherwise poor quality profile, to make the high power diode laser applicable for optical tweezers.
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Chamberlain, Debra K. "Materials behaviour in liquid potassium and rubidium." Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280314.
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Chen, Hongxin. "Electromagnetically induced transparency in laser-cooled rubidium." Thesis, Open University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265348.
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Campbell, Gretchen K. (Gretchen Kathleen). "⁸⁷Rubidium Bose-Einstein condensates in optical lattices." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/39295.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, February 2007.Includes bibliographical references (p. 130-142).
Bose-Einstein condensates in optical lattices have proven to be a powerful tool for studying a wide variety of physics. In this thesis a series of experiments using optical lattices to manipulate 87Rb Bose-Einstein condensates are described. A systematic shift of the photon recoil momentum due to the index of refraction of a dilute gas of atoms has been observed. The recoil frequency was measured interferometrically using a two-pulse Ramsey interferometer. The two pulses were created using a one dimensional optical lattice. By measuring the resulting frequency as a function of the lattice detuning from the atomic resonance, we found a distinctive dispersive shape for the recoil frequency that fit the recoil momentum as n,.hk. A one-dimensional optical lattice was used to modify the dispersion relation of the condensate in order to demonstrate the matter-wave analogue of Optical Parametric Generation (OPG) and Amplification (OPA) of photons. A condensate was loaded into a moving optical lattice with adjustable quasimomentum k0. As the value for k0o was varied, we observed elastic scattering into two distinct final momentum states k1 and k2.
(cont.) When a small fraction of atoms was first transferred to k1 before ramping on the lattice, we observed the amplification of scattered atoms into k1 and k2. The superfluid-Mott Insulator transition was studied using microwave spectroscopy in a deep three-dimensional optical lattice. Using the density dependent clock shift we were able to spectroscopically distinguish sites with different occupation numbers, and to directly image sites with occupation number from 1 to 5, revealing the shell structure of the Mott Insulator phase.
by Gretchen K. Campbell.
Ph.D.
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Breuer, John. "Cold elastic collisions of sodium and rubidium." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29690.
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Thesis (M. S.)--Physics, Georgia Institute of Technology, 2010.Committee Chair: Kennedy, Brian; Committee Member: Chapman, Michael; Committee Member: Zangwill, Andrew. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Craig, Samantha L. "Rubidium Oscillator Error Model for Specific Force and Magnetic Field Susceptibility." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1398126124.
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Köhl, Michael. "Kohärente Atomoptik mit dem Atomlaser." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963248472.
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Burger, Sven. "Erzeugung und Untersuchung dunkler Solitonen in Bose-Einstein-Kondensaten." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=959954112.
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Buchkremer, Felix B. J. "Kohärenz in miniaturisierten Speicher- und Leiterstrukturen für neutrale Atome." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=96364548X.
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Schneider, Stephan. "Bose-Einstein-Kondensation in einer magnetischen Z-Falle." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968888291.
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Lundegaard, Lars Fahl. "High-pressure diffraction studies of rubidium phase IV." Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/2757.
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Rb-IV is the stable high-pressure phase of rubidium between 16 and 21 GPa. The structure of Rb-IV has long been known to be complex, but it is only recently that it has been solved as being an incommensurate host-guest composite structure, comprising a tetragonal host framework containing chains of "guest" atoms that form structures incommensurate with the host along their common c- axis. While similar composite structures have been observed in a number of other elemental metals, Rb-IV is unique in that on pressure decrease below 16.7 GPa at 300 K, the chains of guest atoms become disordered and liquid-like. This thesis is a detailed structural study of Rb-IV. High-pressure, combined with high-temperature powder diffraction techniques, have been used to map the P-T phase diagram of rubidium between 15 GPa and 20 GPa and between 298 K and 600 K. The results show that the guest order-disorder transition pressure is strongly temperature dependent, and that the disordered phase is observed to the highest temperatures. Technical developments, which have made it possible to extract reliable modulation reflection intensities from a Rb-IV single crystal, are described. The resulting data are used for a full modulated structure refinement of Rb-IV, revealing a saw-tooth shaped modulation of the guest structure, from which new information on the host-guest interactions has been extracted. Inelastic X-ray scattering techniques have been used to measure the longitudinal acoustic (LA) phonons in a Rb-IV single crystal. Two LA-like phonon branches, one for each of the two composite subsystems, are observed along the common c-axis. The sound velocities in the host and guest structures are determined and the pressure dependence is shown to differ by a factor of two. Finally, developments that will enable future combined high-pressure high- temperature single-crystal diffraction studies, and single-crystal diffraction studies at pressures above 100 GPa, will be presented.
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Chu, Yiwen. "Loading rubidium atoms into a hollow core fiber." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40904.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2007.Includes bibliographical references (p. 71-73).
We demonstrate a procedure for cooling, trapping, and transferring rubidium atoms into a hollow core photonic band gap fiber. The atoms are first collected in a magneto-optical trap (MOT) and then cooled using polarization gradient cooling. Magnetic traps are then used to confine and transfer the atoms toward the face of the fiber. An optical dipole trap formed using laser light propagating through the fiber guide the atoms and confine them away from the fiber walls. We hope to use this system to achieve large optical depths with possible applications to quantum computing.
by Yiwen Chu.
S.B.
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Kowalczyk, Anna Urszula. "Manipulation and control of ultra-cold rubidium atoms." Thesis, Open University, 2013. http://oro.open.ac.uk/54835/.
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During the course of this PhD an experimental set-up has been designed and implemented to confine neutral atoms in microscopic dipole traps and to manipulate their internal states by laser excitation to Rydberg states. A lot of effort was devoted to the stabilization of the laser sources for two-photon excitation to the Rydberg states, using techniques based on modulation transfer spectroscopy and electromagnetically induced transparency (EIT). Taking advantage of the EIT spectroscopy scheme, we have measured for the first time the electric dipole moments for the transitions between the first excited 5P3/2 and Rydberg nDS/2 level of rubidium. These measurements provided benchmarking of existing theoretical models to calculate the reduced matrix elements and have helped us to identify the D'yachkov Pankratov method as a particularly reliable one. Therefore we made use of the existing code to calculate the relative radial matrix elements for bound-bound, bound-free and free-free transitions between arbitrary states of alkali atoms. Our results allowed us to identify many features of interest and several Cooper minima have been revealed for the first time. The preparation of a new apparatus required ultra-high vacuum for efficient laser cooling and trapping experiments. A unique 4-beam magneto-optical trap has been designed and implemented in our new system. The tetrahedral MOT operating at a very acute beams angle has been demonstrated for the first time. The characterisation of the basic properties of our MOT has highlighted. some interesting new cooling mechanisms that do not fully match existing theoretical models and will require further investigation. It has been demonstrated that our tetrahedral MOT is suitable to prepare cold, diluted reservoirs of atoms and therefore efficiently load our microscopic dipole trap.
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Chen, Sophia Lee. "Two-Photon Direct Frequency Comb Spectroscopy of Rubidium." Oberlin College Honors Theses / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1337650567.
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Wu, Sheldon Shao Quan. "Hydrocarbon-free resonance transition 795 nm rubidium laser." Diss., [La Jolla] : University of California, San Diego, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p3356349.
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Thesis (Ph. D.)--University of California, San Diego, 2009.Title from first page of PDF file (viewed July 9, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 110-113).
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Singh, Swati. "Progress towards ultra-cold ensembles of rubidium and lithium." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/32067.
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The work described in this thesis is related to various projects that I worked on towards the production of ultra-cold ensembles of ⁸⁵Rb, ⁸⁷Rb and fermionic ⁶Li. In the past few years, ultra-cold atomic gases have evolved into a mature field of research, driving various theoretical and experimental groups towards new possibilities. This thesis starts with an overview of the research direction of the field and the lab in particular, to use ultra-cold fermionic atoms as quantum simulators for several condensed matter problems. It discusses the experimental route to quantum degeneracy in a sample of ultra-cold atoms and techniques to get there. The rest of the thesis primarily discusses the first step to degeneracy- production of ultra-cold ensembles of rubidium and lithium. It starts with the theoretical concepts that enable laser cooling and trapping. The interaction between light and atoms and how it leads to a decrease in temperature of the ensemble is discussed. The limits of different cooling mechanism with relevance of the atoms of interest are described. The starting point for all laser cooling experiments is an atomic source, the details of the requirements and efficiency of different atomic sources is discussed, emphasizing our choice of sources for the two atoms. Other technical details such as the vacuum system and the control system for the experiment are briefly discussed. Preliminary data from our first ensembles of ultra-cold lithium and rubidium is shown. At the end, the planning and progress of the first experiments that we aim to achieve with these ultra-cold atoms namely looking for Feshbach resonances and studying the effect of DC electric fields on them, and studies with ultra-cold lithium atoms in optical lattices, is discussed.Science, Faculty of
Physics and Astronomy, Department of
Graduate
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Buggle, Christian. "Collective and collisional properties of the Rubidium quantum gas." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2005. http://dare.uva.nl/document/78220.
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McCabe, David J. "The formation of ultracold rubidium molecules using ultrafast photoassociation." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:65e44f72-1995-45f0-8751-898735e54b6e.
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The establishment of robust laser-cooling techniques for the formation of ultracold atoms has provided a test-bed for low-temperature science, with scattering events changing character from incoherent thermal interactions to coherent quantum mechanical events. A natural extension is the pursuit of ultracold molecules in prescribed low-energy internal states. Atomic cooling techniques, however, do not generalize to the molecular regime due to the complex energy-level structure afforded by its extra degrees of motion. An indirect approach to ultracold molecule formation - photoassociation using ultrafast laser pulses - is the focus of this thesis. A broadband field associates atom pairs into a localized molecular wavepacket that evolves within the attractive excited-state potential. A suitably timed dump pulse may thus be applied to stabilize population into deeply bound ground vibrational states. This strategy may be generalized to any species whose spectroscopy matches the pulse spectrum, and offers a coherent population transfer scheme that does not require precise knowledge of the system. This thesis presents experiments using high-energy photoassociation pulses applied to ultracold rubidium atoms. The pulses quench the background ground-state molecular population but form bound dimers within the excited state. A pump-probe experiment was designed to chart the excited-state dynamics; however, the oscillations predicted by theoretical calculations were not evident in the molecular signal. The nature of the dynamics is expected to be strongly dependent on the initial state of the atom pairs addressed by the ultrafast pulse: a bound molecular population provides an additional candidate to free atoms. A spectroscopic measurement characterizes these bound molecules and identifies their formation mechanism. A subsequent experiment provides evidence that the predominant contributor to the pump-probe signal is the unbound initial population. The consequences with regard to both the observation of excited-state dynamics and the subsequent application of a dump pulse are discussed.
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Sheard, Benjamin T. "Magnetic transport and Bose-Einstein condensation of rubidium atoms." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:dedece2b-c33a-415b-9d6b-570263042797.
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This thesis describes the design, construction and optimisation of a new apparatus to produce Bose-Einstein condensates (BECs) of 87Rb atoms. The main aim in building this system was to include a high resolution imaging system capable of resolving single atoms. Optical access for the imaging system was created by including a stage of atom transport in which the atoms are magnetically transferred ~50 cm from a magneto-optical trap (MOT), where they are initially collected, to a glass science cell where experiments are carried out and imaging takes place. Two magnetic transport schemes have been demonstrated, based on approaches first used in other laboratories. First, a scheme in which the atoms are transferred in a moving pair of magnetic trapping coils. Second, a hybrid scheme where the atoms are translated part of the distance in the moving coils, and the rest of the way by switching the current in a chain of fixed coils. This second scheme was designed to allow optical access for a high numerical aperture microscope objective to be placed immediately next to the science cell for high resolution imaging. The atoms were first collected in a large pyramid MOT which can be loaded with 3 × 10^9 atoms in a time of 20 s. Around half of these atoms – those in the |F = 1, mF = −1> magnetic substate – were then magnetically trapped prior to transport. The typical fraction of the trapped atoms transferred to the science cell was ~30% and ~18% for the moving coils and hybrid schemes respectively. Evaporative cooling was carried out on the atom cloud following transport with the moving coils and loading into a time-orbiting potential trap. The optimised cooling sequence lasted for 28 s and consistently produced a pure condensate with 5 × 10^5 atoms. A BEC has also been produced by evaporative cooling following hybrid transport. The next experimental steps will be to optimise the hybrid transfer approach further and install the high resolution imaging system. The system is well-placed to continue an ongoing series of experiments in which ultracold atoms are trapped in RF-dressed potentials. These potentials will be used to study low-dimensional quantum gases as well as in experiments where small atom number BECs are rapidly rotated to enter the fractional quantum Hall regime.
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Harris, Magaret L. "Realisation of a cold mixture of rubidium and caesium." Thesis, Durham University, 2008. http://etheses.dur.ac.uk/2300/.
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This thesis describes a new apparatus designed to study cold, ultracold, and quantum degenerate mixtures of rubidium and caesium atoms. The Rb- Cs mixture is prepared using a double magneto-optical trap (MOT) system in which a two-species pyramid MOT acts as a source of cold atoms for a 'science' MOT. The first results of experiments on the magneto-optically trapped mixture are presented, including measurements of trap loss rates due to single-species and interspecies inelastic collisions. A technique for reducing interspecies loss by spatially separating the MOTs during loading is described. This technique allows 50-50 mixtures of Rb and Cs atoms to be loaded into a magnetic trap at close to their respective maximum single- species atom numbers. Alternatively, one species can be loaded with arbitrarily small amounts of the other. The displaced MOT technique is thus аn excellent starting point for investigations of interspecies Feshbach resonances and sympathetic cooling of Rb-Cs mixtures in magnetic and optical traps. In addition, a model of polarisation spectroscopy based on numerical integration of population rate equations is described. Theoretical polarisation spectra generated by the model are shown to agree with experimental spectra for the F = I + 1/2 → F' transitions in Rb and Cs. An investigation of the sub-Doppler dichroic atomic vapour laser locking (DAVLL) technique demonstrates how locking signals can be optimised for the Rb D2 transitions. The role of polarisation purity in generating the spectra is discussed, and impurities are modeled using a Jones matrix approach. Comparisons with polarisation spectroscopy and DAVLL are used to enhance understanding of atom-light interactions in spectroscopic systems, and indicate methods for optimising locking signals for use in cold atom experiments.
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Nortier, F. M., H. T. Bach, E. R. Birnbaum, J. W. Engle, M. E. Fassbender, J. F. Hunter, K. D. John, et al. "Rubidium metal target development for large scale 82Sr production." Helmholtz-Zentrum Dresden - Rossendorf, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-164250.
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Strontium-82 (t1/2 = 25.5 d) is one of the medical isotopes produced on a large scale at the Isotope Production Facility (IPF) of the Los Alamos National Laboratory (LANL), employing a high intensity 100 MeV proton beam and RbCl targets. A constant increase in the 82Sr demand over the last decade combined with an established thermal limit of molten RbCl salt targets [1,2] has challenged the IPF’s world leading production capacity in recent years and necessitated the consideration of low-melting point (39.3 °C) Rb metal targets. Metal targets are used at other facilities [3–5] and offer obvious production rate advantages due to a higher relative density of Rb target atoms and a higher expected thermal performance of molten metal. One major disadvantage is the known violent reaction of molten Rb with cooling water and the potential for facility damage following a catastrophic target failure. This represents a significant risk, given the high beam intensities used routinely at IPF. In order to assess this risk, a target failure experiment was conducted at the LANL firing site using a mockup target station. Subsequent fabrication, irradiation and processing of two prototype targets showed a target thermal performance consistent with thermal modeling predictions and yields in agreement with predictions based on IAEA recommended cross sections [6].
Target failure test: The target failure test bed (FIG. 1) was constructed to represent a near replica of the IPF target station, incorporating its most important features. One of the most vulnerable components in the assembly is the Inconel beam window (FIG. 2) which forms the only barrier between the target cooling water and the beam line vacuum. The test bed also mimicked relevant IPF operational parameters seeking to simulate the target environment during irradiation, such as typical cooling water flow velocities around the target surfaces. While the aggressive thermal effects of the beam heating could not be simulated directly, heated cooling water (45 °C) ensured that the rubidium target material remained molten during the failure test. A worst case catastrophic target failure event was initiated by uncovering an oversized predrilled pinhole (1 mm Φ) to abruptly expose the molten target material to fast flowing cooling water.
Prototype target irradiations: Two prototype Rb metal target containers were fabricated by machining Inconel 625 parts and by EB welding. The target containers were filled with molten Rb metal under an inert argon atmosphere. Follow-ing appropriate QA inspections, the prototype targets were irradiated in the medium energy slot of a standard IPF target stack using beam currents up to 230 µA. After irradiation the targets were transported to the LANL hot cell facili-ty for processing and for 82Sr yield verification.
During the target failure test, cooling water conductivity and pressure excursions in the target chamber were continuously monitored and recorded at a rate of 1 kHz. Video footage taken of the beam window and the pinhole area combined with the recorded data indicated an aggressive reaction between the Rb metal and the cooling water, but did not reveal a violent explosion that could seriously damage the beam window. These observations, together with thermal model predictions, provided the necessary confidence to fabricate and fill prototype targets for irradiation at production-scale beam currents. X-ray imaging of filled targets (FIG. 3) shows a need for tighter control over the target fill level. One prototype target was first subjected to lower intensity (< 150 µA) beams before the second was irradiated at production level (230 µA) beams. During irradiation, monitoring of cooling water conductivity indicated no container breach or leak and, as anticipated given the model predictions, the post irradiation target inspection showed no sign of imminent thermal failure (see FIG. 4). Subsequent chemical processing of the targets followed an established procedure that was slightly modified to accommodate the larger target mass. TABLE 1 shows that post chemistry 82Sr yields agree to within 2 % of the in-target production rates expected on the basis of IAEA recommended cross sections. The table also compares 82Sr yields from the Rb metal targets against yields routinely obtained from RbCl targets, showing an increase in yield of almost 50 %.
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Pursehouse, James. "Electron and photon interactions in magnesium, calcium and rubidium." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/electron-and-photon-interactions-in-magnesium-calcium-and-rubidium(cf98e2a6-ae7d-45b9-91c4-33f148a5678e).html.
Full textAbstract:
In the experiments detailed in this thesis, a series of scattering experiments were conducted in a versatile scattering chamber. In order to conduct these experiments, various electronic equipment was designed and built, including new computer controlled electron analyser power supplies. This new equipment was tested, adopted in this work, and is described in this thesis. The superelastic scattering technique was used on magnesium atoms to obtain a set of atomic collision parameters (ACPs), which describe the interaction. This was achieved by exciting a beam of magnesium atoms to the 3(1)P(1) excited state using resonant laser radiation around 285 nm, and using an electron beam with well defined momentum to de-excite the atoms. The momentum of the outgoing electrons was measured as the polarisation and scattering angle were varied, to obtain the ACPs. These measurements were carried out over an angular range of 30 degrees to 120 degrees and with incident energies equivalent to 35 eV, 40 eV, 45 eV, and 55 eV. A set of theoretical data was compared to the experimental results and found to be reasonably accurate at describing the interaction. Laser-aligned and ground-state (e,2e) ionisation measurements were taken from the 4(1)S(0) and 4(1)P(1) states of calcium. The measurements were taken with the energy of the scattered and ejected electrons set at 30 eV, and with one outgoing electron angle set to 45 degrees. The differential cross section was determined for a range of angles of the second electron, ranging from 30 degrees to 65 degrees. The incident and outgoing electron momenta were all defined in the same plane with the laser polarisation being in a plane perpendicular to the incident electron. The laser aligned (e,2e) measurements were compared to two theoretical models, one of which (a 3DW model) predicted an identically zero cross section when the laser polarisation was perpendicular to the scattering plane. The other model (a TDCC model) predicted a non-zero cross section, in agreement with the experiment. Simultaneous time-resolved two-colour photoionisation from the 5(2)P(3/2) and 6(2)P(3/2) states of rubidium was also conducted. These experiments investigated two pathways to creating 0.36 eV photoelectrons from rubidium. Photoelectrons were produced by either using laser radiation at ~780 nm to resonantly excite atoms to the 5(2)P(3/2) state followed by laser radiation at ~420 nm to ionise the atoms, or laser radiation at ~420 nm was used to resonantly excite atoms to the 6(2)P(3/2) state followed by radiation at ~780 nm which then ionised the atoms. Ionisation differential cross sections were measured over a full 360 degrees by rotating the laser polarisation vectors. By selectively detuning the laser beam so as to select individual ionisation pathways, and then by tuning both lasers to resonance, quantum interferences between the pathways that lead to ionisation were observed.
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Elnour, Huzifa Mohammed Ahamed Mohammed. "Development of a magneto optical trap for Rubidium 87." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85586.
Full textAbstract:
Thesis (MSc)-- Stellenbosch University, 2013.ENGLISH ABSTRACT: A Magneto Optical Trap (MOT) is a configuration formed by three orthogonal pairs of counterpropagating circularly polarized laser beams and a magnetic field gradient. A MOT is used to cool, capture and trap large numbers of atoms in vacuum at very low temperature in K range. In this thesis the development of an experimental setup for realising a MOT of 87Rb atoms is presented. The atomic structure of Rb and the theoretical background of laser cooling and magneto optical trapping was reviewed. The influence of rubidium background pressure in the vacuum system, the laser beam size and the power and frequency on the number of the trapped atoms were studied in literature. The trapping and repumping lasers were characterised experimentally. Six circularly polarised trapping beams with equal power were formed and properly aligned to intersect at the center of the trapping cell. Two optical setups were designed and exploited to investigate and optimise the trapping beam polarisation. The repumping laser beam was successfully aligned and colinearly combined into all the trapping beams. Three different experimental setups for saturated absorption spectroscopy were developed. Saturated absorption spectra showing the hyperfine structure of both 85Rb and 87Rb isotopes were measured and are discussed. Using two saturated absorption spectroscopy setups, the frequencies of both lasers were successfully locked to the trapping and repumping transitions of 87Rb respectively. A rectangular trapping cell was designed and attached to the vacuum system. A pressure of about 10¯7 mbar was achieved. The magnetic field coils were characterised and affixed on both sides of the cell in an anti-Helmholtz configuration. Setups for imaging and quantification of the 87Rb atoms in the MOT were designed. Finally, the procedures for demonstrating a MOT are presented. In conclusion, the current status of the project is reported, with recommendations for the future work.
AFRIKAANSE OPSOMMING: ’n Magneto optiese val (Magneto Optical Trap, MOT) is ’n konfigurasie wat gevorm word deur drie ortogonale laserbundelpare, wat elk uit twee sirkelvormig gepolariseerde bundels met teenoorgestelde voortplantingsrigtings bestaan, en ’n magneetveld gradient. ’n MOT word gebruik om ’n groot aantal atome af te koel, te vang en vas te hou in vakuum by ’n baie lae temperatuur in die K bereik. In hierdie tesis word die ontwikkeling van ’n eksperimentele optelling vir die realisering van ’n MOT van 87Rb atome voorgelê. Die atoomstruktuur van Rb en die teoretiese agtergrond van laser afkoeling en ’n magneto optiese val is hersien. Die invloed van die rubidium agtergronddruk in die vakuumstelsel, die grootte van die laserbundels en die laser drywing en frekwensie op die aantal gevangde atome is bestudeer uit die literatuur. Die MOT-laser en die optiese pomplaser is eksperimenteel gekarakteriseer. Ses sirkelvormig gepolariseerde MOT-laserbundels met gelyke drywings is gevorm en behoorlik belyn om in die middel van die MOT-sel te kruis. Twee optiese opstellings is ontwerp en gebruik om die polarisasie van die MOT-laserbundels te ondersoek en te optimeer. Die optiese pomplaserbundel is suksesvol belyn en ko-liniêr ekombineer met al die MOT-laserbundels. Drie verskillende eksperimentele opstellings vir versadigde absorpsie spektroskopie is ontwikkel. Versadigde absorpsie spektra wat die hiperfyn struktuur van beide die 85Rb en 87Rb isotope toon is gemeet en bespreek. Deur twee versadigde absorpsie spektroskopie opstellings te gebruik is die frekwensies van beide lasers suksesvol gestabiliseer op die MOT- en optiese pomp-oorgange van 87Rb onderskeidelik. ’n Reghoekige MOT-sel is ontwerp en aangesluit by die vakuumstelsel. ’n Druk van ongeveer 10¯7 mbar is bereik. Die magneetveld spoele is gekarakteriseer en weerskante van die sel gemonteer in ’n anti-Helmholtz konfigurasie. Ten einde word die prosedures vir die demonstrasie van ’n MOT voorgelê. In die gevolgtrekking word daar verslag gedoen oor die status van die projek, met aanbevelings vir toekomstige werk.
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Johnson, Luke Anthony Mavilio. "Precision laser spectroscopy of rubidium with a frequency comb." Thesis, University of Leeds, 2011. http://etheses.whiterose.ac.uk/4375/.
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The development of the optical frequency comb technique has transformed the field of spectroscopy, allowing the measurement of atomic transition frequencies to unprecedented levels of accuracy. In this thesis a frequency comb has been used to make absolute frequency measurements of optical transitions to highly excited Rydberg levels in Rb. The reliable measurement of these levels plays an important role in improving the accuracy of atomic models and the widely used Rb atom is an excellent candidate for such studies. A laser system has been constructed and optimised for resolving these highly excited states in an ordinary vapour cell, using a Doppler-free technique of purely optical detection. After several developments to the apparatus, the absolute energies of a collection of Rydberg levels have been measured to an accuracy of 3 parts in 1010, demonstrating the first sub-megahertz accuracy optical Rydberg spectroscopy. A vapour cell is a convenient and straightforward solution for finding Rydberg levels and these findings show that cell-based detection techniques could potentially permit rapid advances in the field. Along the way, the vapour cell sample has also highlighted many interesting areas of exploration: For example, it has allowed long term laser stabilisation to Rydberg levels for experiments such as the micromaser. Also, the Rydberg atoms in the cell have been manipulated by microwaves, allowing the study of high ` = 4 states, which has illuminated a whole range of new experiments. It has even been found that one of the limiting factors of these cell-based schemes may be the knowledge of the frequency of lower lying transitions, which has ultimately led this research into a secondary area, involving the measurement of the Rb D lines with a frequency comb. Together, these findings have exposed a large variety of atomic physics to be investigated in the future.
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Guinea, William Edward. "Polarisation and Alignment Studies in Electron Scattering From Rubidium." Thesis, Griffith University, 2009. http://hdl.handle.net/10072/367197.
Full textAbstract:
Measurements have been made of the A2 spin asymmetry in the scattering of polarised
electrons from rubidium atoms. Results have been taken at an incident energy of 15,
20, 30, 50 and 80eV for elastic scattering, and at 15, 20, 30 and 50eV for 5S to 5P
excitation where the fine structure has not been resolved. The measurements covered
the angular range 30° to 110°. Results were taken using a crossed beam type
experiment, with a hemispherical electrostatic detector. Polarised electrons were
provided by a conventional gallium arsenide spin-polarised electron source. The Rmatrix
and relativistic distorted wave calculations available demonstrate good
agreement with the experimental results, though there are some clear discrepancies
between the magnitudes and positions of the extrema as predicted by theory. These A2
results follow on from those taken by Went (2003).
A study of the autoionisation resonances of rubidium has also been undertaken. This
consisted of first measuring the angular variation of the autoionisation resonances in
the angular range 30° to 130°, at an incident energy of 1keV. A crossed beam method
was also used for these results, though electrons were provided by a conventional
electron gun. Significant relative angular variation between sets of autoionisation
resonances was observed. The results taken represent the first experimentally
determined values of the alignment parameter, A20 and R0, the isotropic distribution
ratio for the leading autoionisation doublet of rubidium. The experimentally
determined values of A20 and R0 were not inconsistent with the theoretical values
available for comparison.
Finally an attempt was made to measure a circular dichroism in the angular
distribution of autoionised electrons due to stepwise laser/electron impact excitation
(CPDAD). The experimental detection of such a circular dichroism would be the very
first of its kind. Such a measurement would also help validate the theoretical approach
that predicted its existence. Preliminary investigation requires identification of an
autoionisation resonance that is enhanced with the stepwise excitation procedure. A
crossed beam experiment identical to the procedure immediately above was
undertaken using a conventional electron gun. Laser light resonant with the D2 line of rubidium was provided by a titanium-sapphire laser, while a diode laser was used to
repump the dark state. Measurements were taken at incident energies of 250, 450, 700
and 1000eV at ejected electron angles of 75°, 75°, 90° and 90° respectively. No
enhancement was visible with the stepwise process for any of the observed
autoionisation resonances, so it was not possible to study CPDAD.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Physical sciences
Science, Environment, Engineering and Technology
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Carradus, Maria. "Structural studies of Na'+K'+-ATPase." Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342323.
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Hopkins, Stephen Antony. "Laser cooling of rubidium atoms in a magneto-optical trap." n.p, 1995. http://oro.open.ac.uk/19431/.
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Zhang, Zhaonian. "Impact of rubidium clock aiding on GPS augmented vehicular navigation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0023/MQ31407.pdf.
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Saha, Satyajit. "Parity nonconserving neutron spin rotation in bromine, cesium and rubidium /." Thesis, Connect to this title online; UW restricted, 1990. http://hdl.handle.net/1773/9663.
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Hopkins, Stephen. "Laser cooling of rubidium atoms in a magneto-optical trap." Thesis, Open University, 1996. http://oro.open.ac.uk/19431/.
Full textAbstract:
This thesis describes theoretical and experimental work concerning radiation forces on atoms, with particular reference to rubidium atoms confined in a magneto-optical trap. After a short history of the field of laser cooling, a review of the semiclassical theory of mechanical interactions between two-level atoms and electromagnetic radiation is given. Different formulations of the semiclassical theory are discussed, including a new formulation in terms of momentum transfer amongst the plane wave modes of the electromagnetic field. Two important applications of light forces on atoms, namely 'optical molasses' and the 'magneto-optical trap', are then described with emphasis on experimental parameters. Three sub-Doppler cooling mechanisms, 'sisyphus cooling', 'motion-induced orientation cooling' and the 'magnetically-assisted sisyphus effect', are described and their role in optical molasses and the magneto-optical trap is discussed. A new study of the polarisation gradients which occur in 3-D monochromatic light fields is presented and quantifies their relative presence in different light field configurations. Polarisation gradient parameters are developed and shown to be directly related to the relativistic spin tensor of the light field. Implications of this polarisation gradient study for laser cooling work are discussed. The design, construction from scratch, operation and testing of a magneto-optical trap for rubidium are described, including novel designs for two vacuum cells. Preliminary experiments to characterise the trap are described and results are presented; they primarily concern the number and distribution of atoms in the trap. Finally. the theory of time domain spectroscopy is reviewed. The construction and testing of a pulsed dye laser for study of coherent transients in samples of laser-cooled atoms and a proposed experiment to measure the temperature of cold atoms using coherent transients are described. Factors expected to influence the shape of coherent transients in cold atoms are discussed.
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Streed, Erik William. "⁸⁷Rubidium Bose-Einstein condensates : machine construction and quantum Zeno experiments." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34400.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2006.Includes bibliographical references (p. 121-130).
This thesis details construction of a new apparatus for the production of 87Rb Bose-Einstein condensates and a subsequent quantum Zeno effect experiment. An experimental apparatus for producing large Bose-Einstein condensates of 87Rb is described in detail. A high flux thermal atomic beam is decelerated by a Zeeman slower and is then captured and cooled in a magneto-optical trap. The atoms are then transfered into a cloverleaf style Ioffe-Pritchard magnetic trap and cooled to quantum degeneracy with radio frequency induced forced evaporation. Condensates containing up to 20 million atoms can be produced every few minutes. The quantum Zeno effect is the suppression of transitions between quantum states by frequent measurement. Oscillation between two ground hyperfine states of a magnetically trapped 87Rb Bose-Einstein condensate, externally driven at a transition rate WR, was substantially suppressed by destructively measuring one of the levels with resonant optical scattering. While an ideal continuous measurement will stop the transition, any real measurement method will occur at a finite rate. The suppression of the transition rate in the two level system was quantified for pulsed measurements with a time between pulses t and weak continuous measurements with a scattering rate y. We observe that the weak continuous measurements exhibit the same suppression in the transition rate as the pulsed measurements when ySt = 3.60(0.43). This is in agreement with the previously predicted value of 4. Increasing the measurement frequency suppressed the transition rate to 0.005WR.
by Erik William Streed.
Ph.D.
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Federicci, Rémi. "Étude des propriétés diélectriques dans le dititanate de rubidium : Rb2Ti2O5." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066589/document.
Full textAbstract:
Les travaux présentés dans ce manuscrit traitent de l'étude du dititanate de rubidium de stoechiométrie Rb$_{2}$Ti$_{2}$O$_{5}$. Ce matériau a été synthétisé dans les laboratoires du LPEM, en collaboration avec l'Institut des Matériaux Jean Rouxel de Nantes. Le procédé de synthèse par voie chimique est présenté de façon détaillée dans le manuscrit. Une caractérisation par diffraction de rayons X en fonction de la température, réalisée sur poudre et monocristal a montré que le groupe d'espace du composé est C2/m. Des calculs de relaxation structurale utilisant la théorie de la fonctionnelle de densité (DFT ) par méthode ab initio sont venus confirmer ces résultats. Une étude des modes vibratoires du réseau cristallin par spectroscopie Raman et IR en fonction de la température est aussi présentée dans ce manuscrit. Des calculs DFT sur les modes vibratoires du Rb$_{2}$Ti$_{2}$O$_{5}$ sont également présentés pour compléter l'étude spectroscopique. Des études par Microscope Electronique à Transmission ainsi que Microscope Electronique à Balayage viennent ajouter des informations sur la structure cristalline et la topographie du matériau. La majeure partie des travaux présentés dans ce manuscrit concerne des mesures de transport réalisées sur ce composé. Cette étude se compose d'un ensemble de mesures comportant des cycles I-V, Q-V et des mesures de permittivité en fréquence, le tout sur une large plage de température (100\,K-400\,K). Une valeur colossale de la permittivité relative (10$^8$) avec une variation de six ordres de grandeurs entre les basses et hautes fréquences, ainsi que des signatures dans les courants de polarisation de déplacement attestant d'un comportement de type ferroélectrique ont été mis en évidence. Nous avons montré que les échantillons de Rb$_{2}$Ti$_{2}$O$_{5}$ sont très faiblement conducteurs électroniquement mais de bons conducteurs ioniques. Nous avons mis en évidence des propriétés d'accumulation de charge ionique donnant lieu à des macro-dipôles expliquant une valeur colossale de la constante diélectrique. Ces propriétés s'activent dans une plage de température comprise entre 200K et 330K. Nous avons de surcroît démontré que ce matériau offrait de manière intrinsèque les propriétés d'un système de permittivitéThe work described in this thesis report deals with the dielectric investigation of the rubidium peroxititanate with stoechiometry Rb$_{2}$Ti$_{2}$O$_{5}$. This material has been synthetized in the LPEM (ESPCI Paris) with the collaboration of Institut des Matériaux Jean Rouxel (Nantes, France). The synthesis process is based on chemical solid state reactions and is detailed in this report. An X-Ray diffraction caracterization as function of the temperature was realized on powders and single cristals and showed that the material structure is C2/m. Structural relaxation computations using Density Functional Theory (DFT) confirmed these results. A deep investigation of the phonon modes by means of Raman and Infrared spectroscopy as function of temperature was also performed and results are presented and discussed in the thesis. DFT computations of the phonon modes of the Rb$_{2}$Ti$_{2}$O$_{5}$ are also displayed to finalize the structural study. Transverse Electron Miscroscopy and Scanning Electron Microscopy also brought useful information concerning the crystal structure and the topography of the materials. The main part of the work presented in this thesis is related to electrical transport measurements performed on Rb$_{2}$Ti$_{2}$O$_{5}$ crystals. This study consists of a temperature dependence investigation of I-V and Q-V cycles as well as permittivity measurements as function of frequency. We report a colossal relative permittivity (10$^8$) with a variation of almost six order of magnitude between low and high frequencies, and signatures in the displacement currents attesting of a huge variation of polarization due to ferroelectic-like behavior. We showed that the samples of Rb$_{2}$Ti$_{2}$O$_{5}$ are very weak electronic conductors (10$^{-9}$\,S.cm$^{-1}$) but very good ionic conductors (10$^{-3}$\,S.cm$^{-1}$). We have evidenced ionic charge accumulation properties giving rise to macro-dipoles explaining this colossal dielectric constant value. These properties were found to be activated within a temperature range of 200\,K -330\,K. In addition it was demonstrated that this material genuinely behaves as a memristive system
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Wennberg, Ulrika. "On Demand Generation of Single Photons Locked to Rubidium Transitions." Thesis, KTH, Tillämpad fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279444.
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Zhang, Yuhong. "OBSERVATION OF EIT IN RUBIDIUM VAPOR USING THE HANLE EFFECT." Miami University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=miami1186165356.
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Nirrengarten, Thomas. "Piégeage magnétique d'atomes de Rubidium au voisinage d'une surface supraconductrice." Paris 6, 2007. https://tel.archives-ouvertes.fr/tel-00410067.
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Le but des expériences de puces à atomes est la réalisation de micropièges magnétiques et la manipulation très précise d'un nuage d'atomes refroidis. La présence de la surface de la puce à proximité des atomes peut toutefois se révéler gênante pour le piégeage. Les fluctuations du champ magnétique induites par le bruit de courant dans la puce engendrent des pertes et diminuent le temps de vie dans le piège. Ce bruit est dû à la résistivité finie du métal utilisé pour réaliser la puce. Des modèles théoriques présentés dans cette thèse laissent penser que l'utilisation de pistes supraconductrices pourrait réduire ces pertes. Nous décrivons ensuite le dispositif cryogénique et la séquence expérimentale qui nous ont permis d'observer le premier piège magnétique sur puce supraconductrice. Le temps de vie à 440 microns de la surface avoisine deux minutes ce qui est très prometteur. Nous présentons enfin l'étape de refroidissement du nuage jusqu'à l'obtention d'un condensat de Bose-Einstein.
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Romanov, Gleb Vladimirovich. "Optical Control of Multi-Photon Coherent Interactions in Rubidium Atoms." W&M ScholarWorks, 2017. https://scholarworks.wm.edu/etd/1516639561.
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In the last few decades, coherent light-atom interactions have opened unprecedented possibilities for the coherent control of atomic and optical quantum systems, paved the way for the practical realization of quantum information technologies, and allowed for the creation of novel quantum-enhanced sensors. This dissertation investigates the interaction of multiple near-resonant optical fields with hot rubidium atoms under the conditions of electromagnetically induced transparency. The main goal of the presented research is to address some fundamental challenges in using such systems for practical applications. The EIT effect relies on the strong coupling of an optical probe field and a collective long-lived ensemble of atomic spins by the means of a strong classical optical control field in a Lambda configuration. While optically-thick atomic vapor is necessary to achieve such a strong coupling regime, the increasing optical depth of the atomic ensemble also leads to the effective enhancement of other nonlinear light-atom interactions, such as the four-wave mixing effect. Here we discuss the possibility to control four-wave mixing in a three-level system without deteriorating the coherent properties of EIT by introducing an additional absorber resonant exclusively with the Stokes field. The exclusive detection of a weak probe field in the presence of a strong control field is a challenging experimental task, especially at the few-photon level. Many experiments employ polarization and/or frequency filtering to compete the task. We present an alternative filtering technique based on optical vortices for cases when the traditional methods are not sufficient or restrict the experimental arrangements. Finally, we demonstrate the possibility to manipulate the group velocity of a pulsed squeezed vacuum field by using the optical dispersion modification via Zeeman spin coherence in rubidium atoms. By changing the interaction condition, we demonstrate the switch between the ``slow'' and (for the first time) ``fast'' light regime. We also show that increased optical depth simultaneously leads to the enhancement of pulse advancement and the deterioration of squeezing fidelity in the output pulses.