Tesis sobre el tema "Magneto-optical trap"
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Jarvis, Kyle. "The blue-detuned magneto-optical trap". Thesis, Imperial College London, 2018. http://hdl.handle.net/10044/1/63833.
Texto completoBounds, Alistair David. "A Rydberg-dressed magneto optical trap". Thesis, Durham University, 2018. http://etheses.dur.ac.uk/12541/.
Texto completoNguyen, Hai Truong. "Magneto optical trap recoil ion momentum spectroscopy /". Search for this dissertation online, 2003. http://wwwlib.umi.com/cr/ksu/main.
Texto completoHambach, Moritz. "Development of a magneto-optical trap for CaF molecules". Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/54851.
Texto completoElnour, 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.
Texto completoENGLISH 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.
Rushton, Joseph. "A novel magneto-optical trap for integrated atom chips". Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/382951/.
Texto completoMuckley, Eric S. "Constructing a magneto-optical trap for cold atom trapping /". Click here to view, 2009. http://digitalcommons.calpoly.edu/physsp/2.
Texto completoProject advisor: Katharina Gillen. Title from PDF title page; viewed on Jan. 14, 2010. Includes bibliographical references. Also available on microfiche.
Hopkins, Stephen Antony. "Laser cooling of rubidium atoms in a magneto-optical trap". n.p, 1995. http://oro.open.ac.uk/19431/.
Texto completoGrünert, Jan. "Ultracold metastable calcium atoms in a bichromatic magneto-optical trap". [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965196445.
Texto completoHopkins, Stephen. "Laser cooling of rubidium atoms in a magneto-optical trap". Thesis, Open University, 1996. http://oro.open.ac.uk/19431/.
Texto completoPatel, Sunil. "A chirped, pulsed laser system and magneto-optical trap for rubidium". Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/66245/.
Texto completoYu, QinQin. "Characterization of a two-color magneto-optical trap for a spin-squeezed optical lattice clock". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100323.
Texto completoCataloged from PDF version of thesis.
Includes bibliographical references (pages 57-58).
We experimentally realize a magneto-optical trap (MOT) for ytterbium that simultaneously scatters light from two atomic transitions, in order to reduce the minimum magnetic field gradient required for trapping atoms. From the experimental data, we propose a model of the MOT where one transition is responsible for trapping the atoms the other transition is responsible for cooling the atoms. In order to test this model and to better understand the dynamics of this two-color MOT, we perform numerical simulations of the contributions of each transition to the steady-state number of trapped atoms. We then compare the results of the simulations with the experimental results and conclude that the model of the separated trapping and cooling functions is a good model for the two-color MOT. Finally, we examine other elements for which the two-color MOT is possible and derive a condition for the linewidths of the two transitions such that the atoms are trapped.
by QinQin Yu.
S.B.
Van, Dongen Janelle. "Simultaneous cooling and trapping of 6Li and 85/87Rb". Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/351.
Texto completoGattobigio, Giovanni Luca. "Manipulation of a large magneto-optical trap : application to four-wave mixing". Nice, 2008. http://www.theses.fr/2008NICE4022.
Texto completoMartin, Paul. "Development of a Strontium Magneto-Optical Trap for Probing Casimir–Polder Potentials". Thesis, University of Oregon, 2017. http://hdl.handle.net/1794/22797.
Texto completoCook, Eryn. "Laser Cooling and Trapping of Neutral Strontium for Spectroscopic Measurements of Casimir-Polder Potentials". Thesis, University of Oregon, 2018. http://hdl.handle.net/1794/23192.
Texto completoShah, Mudessar H. "Model-independent measurement of the excited fraction in a magneto-optical trap(MOT)". Diss., Manhattan, Kan. : Kansas State University, 2006. http://hdl.handle.net/2097/235.
Texto completoLadouceur, Keith. "Experimental advances toward a compact dual-species laser cooling apparatus". Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2508.
Texto completoMilori, Debora Marcondes Bastos Pereira. "Caracterização de uma armadilha magneto-optica para átomos de sódio em célula de vapor". Universidade de São Paulo, 1994. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-30042009-090336/.
Texto completoAmong the various atomic motion control techniques using radiation pressure magneto-optic trapping has been looked at with great enthusiasm because it produces samples of cold atoms (temperatures about μK), with high densities and confined in small regions of space. Due to these motivations the efforts for developing and characterizing these atoms traps has been high. Once the atom is captured by the magneto-optic trap, it goes through an intense process of desacceleration via Doppler Effect and ends up confined in the potential well genered by the interaction with the magnetically Field. The number and the density of the trapped atoms, the size of the cloud and the loading process are strongly related to trap parameters, such as: magnetic Field gradient, laser beam intensity and background vapor temperature. This work deals with the characterization of a trap of this kind for sodium atoms through a systematic study, in order to discover the conditions for a better performance. At the same time theoretical models are developed in order to understand in depth the atomic forces involved in the production of a new kind of material which is this highly refrigerated gas.
Mancini, Marilia Wellichan. "Perdas colisionais devido ao processo de mudança de estrutura fina em uma armadilha magneto-óptica de rubídio". Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-11092007-110102/.
Texto completoWe report the observation of trap-loss collisional rates due to fine structure changing collisions between cold and trapped 85Rb atoms. We have measured, by photoionization of the atomic fragments in 5P1/2 state originated in these collisions, the rates through the atoms leave the trap induced by this loss mechanism. We carried out experiments to determine the rate dependence with the intensity of the trapping laser, and with the frequency, using the catalisys technique. We also measured the contribution of this process to the total trap-loss rate and determined that fine structure changing is not the dominant loss mechanism. It was also observed that the hyperfine structure plays an important role in the rate behavior. We compared our results with those given by a semiclassical theoretical approach, the Gallagher-Pritchard model, and some disagreements were observed. We proposed some arguments to explain these discrepancies. We believe that such results should stimulate theoretical work on this field.
Salas, Andres David Rodriguez. "Geração de uma armadilha magneto-óptica de estrôncio 88". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-05112012-155605/.
Texto completoThis work presents the construction of the assembly of an experimental system for cooling strontium atoms. The construction of the system is focused on the collective scattering in atomic cold cloud and ultra cold using the Mie theory. The strontium is an element that permits two stage of cooling, the first using the strong transition between singlet states ¹S₀-¹P₁ of Γ=(2π) 32 MHz, and a second stages is the weak transition between singlet and triplet states ¹S₀-³P₁ de Γ=(2π) 7.5MHz. The objective of this work is building the system for cooling strontium atoms using the first transition. The construction of the system is presented in several parts. First is described the construction of oven as vapor source strontium, where the strontium metal is heated to Temperature Range T = 600°C. The oven has a microtubule system responsible for collimating the atomic beam, these microtubules has an internal diameter of D ≈ 180µm and a length of 8mm. After implementation of the oven system and the microtubes were measured transverse velocity profile and the divergence of the atomic beam that leaves the oven, the width value was f wr=(2π)108MHzand beam divergence value was α ≈ 4,12. The second part of the system relies on the construction of the Zeeman slower responsible for decelerating the atoms of the atomic beam using a laser beam antipropagating of λ = 461 nm nm with a circularly polarized , the detuning used after of the characterization of the system was Δ = (2π)580 MHz. Atoms felt the effects of pressure force radiative within a tube length of 0.28m to compensate the Doppler shift due to motion a of atoms used an arrangement of coils in configuration \"spin flip\" to generate the magnetic field to compensate this effect. The third and main part of the system was the construction of magneto-optical trap (MOT), the atoms coming out of the Zeeman decelerator are confined and cooled by a combination of six counterpropagating beams, three of which are retro reflected using the transition Γ = (2π)32MHz, the detuning of the beam after the characterization of the system was Δ = (-2π) 39 MHz and the opposite polarization for each pair of beam in the same direction. After the construction of the system was made the first magneto-optical trap of strontium atoms 88, the temperature of the trap was atoms to the vertical he expansion was Tv = 4.7mK and the horizontal axis TH = 4 mK 4, also was measured loading time of the atoms in the trap tcharge = 0.15s as optical pumping state ³P₂- ³D₂. The lifetime with and without optical pumping was tlife = 0.3s and tlife = 0.03s respectively.
Gattobigio, Giovanni Luca. "Manipulation of a Large Magneto-Optical Trap:application to Four-Wave Mixing". Phd thesis, Université de Nice Sophia-Antipolis, 2008. http://tel.archives-ouvertes.fr/tel-00312718.
Texto completoSilva, Ilde Guedes da. "Estruturas espaciais de átomos de Na em armadilha magneto-óptica". Universidade de São Paulo, 1994. http://www.teses.usp.br/teses/disponiveis/54/54131/tde-21022014-101849/.
Texto completoIn this work we demonstrate the confinement of neutral sodium atoms using the magneto-optical trap, where the atoms were captured directly from the low velocity tail of the room-temperature atomic vapor contained in the closed vacuum cell. We observed besides the cloud shaped, circular structures like a ring of trapped atoms that apeears when we introduce a misalignment among the trapping beams. We studied the behavior of ring radius with respect to several trapping parameters as: magnetic-field gradient, laser intensity, detuning, and misalignment. The experiments were performed in the low density regime (N<10s), so the ring radius is independent of the number of trapped atoms. Hence, the results obtained can be explained using a simple model that takes into account a radial coordinate dependent (or macroscopic) vortex force and the usual magneto-optical trap forces
Glover, Rohan David. "Atomic and optical Collisions with Cold Metastable Neon". Thesis, Griffith University, 2012. http://hdl.handle.net/10072/367016.
Texto completoThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Physical Sciences
Science, Environment, Engineering and Technology
Full Text
Lytle, Christian y Christian Lytle. "Spectroscopy of Neutral Mercury in a Magneto-Optical Trap Based on a Novel Ytterbium Fiber-Amplified Cooling Laser Source". Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621471.
Texto completoMatherson, Kristen Joy. "Laser Cooling Trapping of Metastable Neon and Applications to Collision Measurements". Thesis, Griffith University, 2010. http://hdl.handle.net/10072/367097.
Texto completoThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Physical Sciences
Science, Environment, Engineering and Technology
Full Text
Peñafiel, Edwin Eduardo Pedrozo. "Absorção cooperativa de dois fótons em átomos frios". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-04102011-155751/.
Texto completoIn this work we study the cooperative two-photon absorption in collisional processes between cold trapped sodium atoms. Nonlinear effects require high density samples to be observed. We redesign our experimental system to achieve samples up to 1012 atoms/ cm3 .The key changes were building a spin-flip Zeeman slower, implementing differential pumping between the oven and the chamber and changing the oven´s design. In order to understand and improve the measurement processes we did photoionization from the states 32P1/2 e 32P3/2. With this data we could calculate the ionization cross section for each of these states, which is in agreement with values reported in the literature. These results show that the new design of the system allows a great starting point for measuring of two-photon absorption. An attempt to measure the absorption of two-photon was made. A small increase in the number of ions produced per unit time was observed in a region shifted to the red of about 4.5 GHz from where we initially expected the transition to occur. This probably indicates two-photon absorption. Thus, both the measurement of cross section of states and the attempt to measure the absorption of two photons, provide a solid foundation for understanding what is the best way to obtain more decisive results with regard to cooperative absorption, and the advantages of performance of our system in future experiments.
Souther, Nathan Jon. "Light Shift Measurements of Cold Rubidium Atoms using Raman Pump-Probe Spectroscopy". Miami University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=miami1250622906.
Texto completoPaul, Justin Reiford. "Construction and characterization of a neutral Hg magneto-optical trap and precision spectroscopy of the 61S 0 - 63P0 Hg199 clock transition". Thesis, The University of Arizona, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3717608.
Texto completoIn this dissertation I present theory and experimental results obtained in the Jones research group at the University of Arizona investigating the feasability of neutral Hg as a candidate for an atomic clock. This investigation includes laser-cooling and trapping of several neutral Hg isotopes as well as spectroscopy of the 61S0 - 6 3P0 doubly forbidden clock transition in neutral Hg199.
We demonstrate precision spectroscopy of the ground state cooling/trapping transition of neutral mercury at 254 nm using an optically pumped semiconductor laser (OPSL). This demonstration exhibits the utility of optically pumped semiconductor lasers (OPSLs) in the field of precision atomic spectroscopy. The OPSL lases at 1015 nm and is frequency quadrupled to provide the trapping light for the ground state cooling transition. We get up to 1.5 W single-frequency output power having a linewidth of <10 kHz in the IR with active feedback. We frequency quadruple the OPSL in two external cavity stages to produce up to 120 mW of deep-UV light at 253.7 nm.
I give a detailed characterization of the construction and implementation of the neutral Hg vapor cell magneto-optical trap (MOT). The trap can be loaded in as quickly as 75 ms at background vapor pressures below 10-8 torr. At reduced background pressure (<10-10 torr) the loading time approaches ∼2 sec.
We describe construction and stabilization of a laser resonant with the Hg199 clock transition and the methods employed to find and perform the experimentally delicate spectroscopy of the clock transition. We present experimental results and analysis for our initial spectroscopy of the 61S0 - 63 P0 clock transition in the Hg199 isotope of neutral mercury.
Daily, Jared Estus. "Two-Photon Ionization of the Calcium 4S3D 1D2 Level in an Optical Dipole Trap". Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd713.pdf.
Texto completoPaul, Justin Reiford. "Construction and Characterization of a Neutral Hg Magneto-Optical Trap and Precision Spectroscopy of the 6¹S₀ - 6³P₀ Hg¹⁹⁹ Clock Transition". Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/565889.
Texto completoPereira, Andrea Antunes. "Estudo de colisões inelásticas heteronucleares no sistema rubídio(Rb)/césio(Cs) em regimes de baixas temperaturas". Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-09092008-123340/.
Texto completoDouble trapping of neutral atoms is one of the most recent advances in the study of collisions cold. Experimentally obtained the rates of loss due to the interaction of species alkaline mixed (Cs / Rb). We use a magneto-optical trap mixed operating with beams of high intensity allowing the cooling and containment of the samples successfully. This work is so important because it represents the first step to study the process of formation of molecules heteronucleares cold. A comparison between two techniques of monitoring procedures for cargo of atoms was performed. The results both qualitatively and quantitatively were satisfactory. And the rates of loss of interest and analyze the rates considering the ratio between the masses of atoms involved and focusing on the effect caused by the difference of mass between them thus completing the main objective of this dissertation.
Agyare, Benjamin A. "INVESTIGATION OF ATOMIC MOTION IN OPTICAL LATTICES VIA INTENSITY CORRELATION MEASUREMENT". Miami University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=miami1186171967.
Texto completoAgomuo, John Chidowerem. "Excitation and photoionization of laser-cooled atoms in the AC-driven magneto-optical trap (AC-MOT), using resonant and non-resonant radiation". Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/excitation-and-photoionization-of-lasercooled-atoms-in-the-acdriven-magnetooptical-trap-acmot-using-resonant-and-nonresonant-radiation(1e69ad21-035e-4fc5-a3a5-80a7943e7641).html.
Texto completoMagalhães, Kilvia Mayre Farias. "Obtenção da degenerescência quântica em sódio aprisionado". Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-24012008-083710/.
Texto completoUsing a system composed of a QUIC trap loaded from a slowed atomic beam, we have performed experiments to observe the Bose-Einstein Condensation of Na atoms. In order to obtain the atomic distribution in the trap, we use an in situ out of resonance absorption image of a probe beam to determine the temperature and the density, which are use to calculate the phase space D. We have followed D as a function of the final evaporation frequency. The results show that at 1.65 MHz we crossed the critical value for D which corresponds to the point to start Bose-Condensation of the sample. Due to the low number of atoms remaining in the trap at the critical point, the interaction produce minor effects and therefore an ideal gas model explains well the observations.
Fritsch, Amilson Rogelso. "Montagem e caracterização de uma armadilha magneto-óptica de rubídio". Universidade do Estado de Santa Catarina, 2011. http://tede.udesc.br/handle/handle/2008.
Texto completoCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
In this work we present the building and characterization of a Magneto-Optical Trap (from now on named MOT) for Rubidium atoms. We perform experiments for studying the e¤ect of a broadband light over trapped atoms. In order to carry out this study we used a incandescent lamp which is broad in the wavelength spectrum. We observed in a MOT, with a number of 109 trapped atoms, that the broadband light increases the emitted .uorescence by the cloud of atoms. This could indicate an e¤ective enlargement in the trap e¢ciency. However, we cannot distinguish, based on our experiments, if this di¤erence is due to an increasing in the number of the trapped atoms or if it is just scattered light caused by the increasing in the intensity of the incident light over the cloud. Thus, we did an analysis in the answer of the laser beam versus the variation in the intensity of lasers used for trapping. In a second step, we perform this study but with a lower number of trapped atoms, 108 atoms, and we verify that the heating of the lamps implies in the increasing of the loss of atoms in the trap, diminishing the number of trapped atoms. Hence, this lead us to make a study on the collisions dynamics that are in the trap, in order to understand the in.uence of the temperature on the trap e¢ciency. We observe that a small uniform increasing in the chamber temperature would lead to a great loss in the trap , but the increasing in the temperature caused by the lamps is a local increasing and generates a degassing of the chamber, increasing the quantity of the background vapour.
Neste trabalho apresentamos a construção e caracterização de uma armadilha magneto-óptica, a qual utilizamos para aprisionamento de átomos de Rb. Após a construção da armadilha e sua caracterização, fizemos experimentos para estudar os efeitos da luz de banda larga sobre os átomos aprisionados. Para esse estudo, utilizamos lâmpadas incandescentes que possuem um espectro largo de comprimentos de onda. Verificamos que em uma armadilha com 109 átomos aprisionados, a luz de banda larga aumenta a fluorescência emitida pela nuvem de átomos, tendo fortes indícios que isto representa efetivamente um aumento na eficiência da armadilha. No entanto, com os experimentos que fizemos, não podemos distinguir se essa diferença é referente a um aumento de átomos aprisionados ou apenas espalhamento de luz causado pelo aumento da intensidade de luz incidida sobre a nuvem. Fizemos então uma comparação da resposta dos átomos, frente a variações na intensidade dos feixes de laser utilizados para o aprisionamento. Por motivos que serão discutidos neste trabalho, refizemos esse estudo com um número menor de átomos aprisionados, 108 átomos, e verificamos que o aquecimento das lâmpadas reflete no aumento das perdas na armadilha, diminuindo então o número de átomos aprisionados. Isto nos levou a fazer um estudo sobre a dinâmica das colisões presentes na armadilha, para entendermos a influência da temperatura na eficiência da armadilha. Verificamos que um pequeno aumento uniforme na temperatura da câmara levaria a grandes perdas na armadilha, mas o aumento da temperatura causado pelas lâmpadas é um aumento local, e gera um processo de desgaseificação da câmara, aumentando a quantidade de átomos, "diferentes de Rb", presentes no vapor de fundo.
Magalhães, Kilvia Mayre Farias. "Medida do tempo de vida de estados de Rydberg em átomos frios de 85 Rb". Universidade de São Paulo, 1999. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-21112007-100629/.
Texto completoIn this work we present our first results on lifetime measurement of Rydberg states using cold atoms held in a magneto-optical trap of 85Rb. Lifetime measurements of highly excited states are important for testing modern theories on atom-vaccum interaction, therefore precise measurements are required. The use of cold atoms presents some advantage when compared with conventional techniques. Among them we cam point out the possibility of atomic observation for long periods of time (<100 µs), the atomic density control in order to avoid undesired effects (such collisions and superradiance) which can limit the measurement precision. We present the lifetime measurement of 27D and 38S states and compared the experimental results with theoretical prediction using different models. Some discrepancies are observed, which indicates the need of a large set of measurement for other states in order to indicate the best model.
Jackson, Jarom Silver. "In Situ Magnetic Field Characterization with the Directional Hanle Effect". BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5982.
Texto completoALVAREZ, Ammis Sánchez. "Armadilha magneto ótica de rubídio e mistura de quatro ondas no vapor atômico". Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/18556.
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Facepe
Neste trabalho apresentamos a caracterização de uma armadilha magneto ótica de átomos de Rb construída em nosso laboratório, juntamente com o seu princípio de funcionamento. O resfriamento é feito com lasers de diodo e tem como mecanismo básico a força de pressão de radiação, que é gerada pelos processos de absorção e emissão de fótons, juntamente com a ação de um campo magnético e a polarização dos feixes. O sistema consiste em três pares de feixes contrapropagantes nas direções x, y e z, com polarizações s+ e s, e um campo magnético que varía linearmente no espaço. Conseguimos armadilhar aproximadamente 108 átomos com um tempo de carga da ordem de 2 seg. Em paralelo realizamos medidas de mistura de quatro ondas degenerada em um vapor de átomos de Rb, na configuração de feixes quase-copropagantes. O sinal gerado no processo não linear foi estudado em função da frequência de um dos feixes enquanto o outro tinha sua frequência fixa; e se mostrou independe de qual dos feixes esta sendo sintonizado. Medidas simultâneas da transmissão do feixe de prova indicam que o processo não linear ocorre só na transição cíclica e envolve o grupo de átomos selecionados pelo feixe de frequência fixa.
In this work we present a characterization of magneto optical trap of 87Rb atoms built in our lab, along with its operating principle. The cooling is done with a diode laser and its basic mechanism is the force of radiation pressure, which is generated by the processes of absorption and emission of photons, together with the action of a magnetic field and polarization of the beams. The system consists of three pairs of counterpropagating beams in the x, y and z directions with s+ and s polarizations, and a magnetic field that varies linearly in space. We were able to trap about 108 atoms with a charging time of approximately 2 sec. In parallel we performed degenerate four wave mixing measures in a Rb vapor atoms using a quasi-copropagating beams configuration. The signal generated in the nonlinear process was studied as a function of one of laser’s while keep the other with a fixed frequency; and it showed independent of which of the beams is being tuned. Simultaneous measurements of the transmission of the probe beam indicates that the nonlinear process occurs only in the cyclic transition and involves the group of atoms selected by the beam with fixed frequency.
Hommelhoff, Peter. "Bose-Einstein-Kondensate in Mikrochip-Fallen". Phd thesis, [S.l.] : [s.n.], 2002. http://edoc.ub.uni-muenchen.de/archive/00000702.
Texto completoMuniz, Sérgio Ricardo. "Estudo de Blindagem Óptica em Colisões Frias". Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-06052005-162937/.
Texto completoIn this work, we showed that is possible to suppress most of the inelastic processes that may cause losses of atoms in a magneto-optical trap. Our results reveal that the process of optical shielding (demonstrated by our group, for the first time to photoassociative ionization - Phys. Rev. Lett. 73, 1911 (1994)) is much more general than it was supposed. Even allowing the suppression of ground state collisions and probably any other inelastic process that happens at short internuclear distances. To achieve those results, it was necessary to develop a new trapping technique, which allows the study of cold collisions, even in traps whose confinement potential is small. Thanks to that technique it was possible, for the first time, to observe losses caused by hyperfine changing collisions, in a trap of sodium atoms operating in the D1 line (loaded from a vapor cell). That technique has still allowed us to measure the rate of cold collisions () for the D1 line trap, a result which, until now, did not exist in the literature. To verify the reliability of the results obtained by that technique, we also accomplished measures of in the D2 line and compared those results with other existent ones in the literature (obtained by a different technique). The good agreement among those results, made us confident in saying that this technique, besides being very interesting in the study of shallow traps (due to the intensity of the trapping lasers, or due to the own nature of the trap), it is also quite reliable.
Mancini, Marília Wellichan. "Produção de moléculas frias heteronucleares no estado fundamental". Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-06062007-184808/.
Texto completoIn this work, cold ground-state KRb molecules were produced by photoassociation in a two species magneto-optical trap (MOT) containing 39K and 85Rb. The KRb molecules are produced through photoassociation and detected in the ground state by multiphoton pulsed ionization. We have characterized their translational temperature and measured their formation rate constant. Homonuclear cold molecules 39K2 and 85Rb2 detected in their ground state were also formed in our trap and characterized as well. It is also reported our first efforts towards the realization of photoassociation spectroscopy of the heteronuclear molecules produced in our trap.
Corrêa, Thiago Reginaldo. "Implicações do uso de campos magnéticos oscilantes em um mot de rubídio". Universidade do Estado de Santa Catarina, 2012. http://tede.udesc.br/handle/handle/1969.
Texto completoCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
This work presents a study about infuences that a quadripolar magnetic field periodically time dependent, can promote in a magneto-optical trap (MOT). The intention reflects the interest in finding an oscillating field configuration that enables the capture and provide benefits if compared to the typical process of trapping. In many papers that will be cited here, a MOT uses a magnetic field that promotes a linear steady magnetic field gradient from the center of the trap. Applying experimental results involving magnetic field oscillations, which will be quoted in detail throughout this text, came the initiative to mathematically model the problem and seek a form of oscillation that may result in a more efficient trapping. Numerical results in a one-dimensional model suggests that the number of atoms is strongly aflected by fuctuations, but we have not found, for the modulations suggests in this work, an oscillation model that could provide an increase of the trap atoms. It was noted that the oscillation frequency of the atom is subjected, aflect the amplitude of the oscillations in the number of trapped atoms.
Neste trabalho apresentamos um estudo sobre as influências que um campo quadripolar magnético, periodicamente dependente do tempo, pode promover em uma armadilha magnético-óptica (Magneto Optical Trap - MOT). O objetivo deste trabalho reflete o interesse em encontrar uma configuração de campo oscilante que possibilite o aprisionamento e forneça vantagens em relação ao processo típico de armadilhamento. Em muitos dos trabalhos que serão citados aqui, um MOT utiliza um campo magnético quadripolar estacionário que promove um gradiente de campo magnético linear à partir do centro da armadilha. Usando resultados experimentais envolvendo oscilações no campo magnético, que serão citados mais detalhadamente no decorrer deste texto, surgiu a iniciativa de modelar o problema matematicamente e buscar uma forma de oscilação que possa resultar em um aprisionamento mais eficiente. Resultados numéricos concebidos em um modelo unidimensional sugerem que o número de átomos é fortemente afetado pelas oscilações, mas não foi possível encontrar, para as modulações sugeridas neste trabalho, uma modulação que pudesse fornecer aumento expressivo no número de átomos armadilhados. Foi possível constatar que a freqüência da oscilação a que o átomo é submetido, afetará a amplitude das oscilações no número de átomos armadilhados.
Ashmore, Jonathan P. y n/a. "Laser Cooling and Trapping of Metastable Neon and Applications to Photoionization". Griffith University. School of Science, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060202.153538.
Texto completoAshmore, Jonathan P. "Laser Cooling and Trapping of Metastable Neon and Applications to Photoionization". Thesis, Griffith University, 2005. http://hdl.handle.net/10072/367728.
Texto completoThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Science
Full Text
Campestrini, Iara Maitê. "Estudo do efeito da dessorção atômica induzida por luz na dinâmica de carga de uma armadilha magneto-óptica de rubídio". Universidade do Estado de Santa Catarina, 2013. http://tede.udesc.br/handle/handle/1978.
Texto completoCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
In order to increase the efficiency of magneto-optical traps, yielding a greater number of trapped atoms and long lifetimes, the effect of lightinduced desorption atom source emerges as an adjuvant and no thermal atoms. A prior experimental investigation (FRITSCH, 2011) showed that the number of rubidium atoms trapped increases when a light desorption focuses on the inner walls of the chamber imprisonment, whose material is stainless steel. The light desorption is applied from an incandescent lamp with power equal to 60 mW. The experimental data are adjusted and parameters are determined from the trap, in case of absence of light. Thus, the theoretical model proposed by Zhang et al. (2009) is applied, describing the increase of the number of atoms in the magneto-optical trap when the light desorption is triggered. In this setting, the rate of desorption and adsorption coefficient is estimated at 5x1017 atoms per second and 55 s-1. The combination of this model with that proposed by Monroe et al. (1990), in case of absence of light, perfectly describes the experimental curve generated when the mechanism for obtaining the magneto-optical trap and light desorption are actuated simultaneously. Furthermore, a theoretical prediction for the desorption rate, the rate of charging of magneto-optical trap and maximum number of atoms trapped on the basis of light desorption power is shown graphically.
Com o intuito de aumentar a eficiência das armadilhas magnéto-ópticas, obtendo-se um número maior de átomos aprisionados e longos tempos de vida, o efeito de dessorção atômica induzida por luz surge como uma fonte coadjuvante e não térmica de átomos. Uma investigação experimental prévia (FRITSCH, 2011) comprovou que o número de átomos de rubídio armadilhados aumenta quando uma luz de dessorção incide sobre as paredes internas da câmara de aprisionamento, cujo material é de aço inoxidável. A luz de dessorção aplicada é proveniente de uma lâmpada incandescente com potência igual a 60 mW. Os dados experimentais são fitados e os parâmetros da armadilha são determinados, para o caso sem luz. Com isso, o modelo teórico proposto por Zhang et al. (2009) é aplicado, descrevendo muito bem o incremento do número de átomos presentes na armadilha magnéto-óptica quando a luz de dessorção é acionada. Desse ajuste, a taxa de dessorção e o coeficiente de adsorção são estimados em 5x1017 átomos por segundo e 55 s-1. A união desse modelo com o proposto por Monroe et al. (1990), para o caso sem luz, descreve perfeitamente a curva experimental gerada quando o mecanismo para a obtenção da armadilha magnéto-óptica e a luz de dessorção são acionados simultaneamente. Além disso, uma previsão teórica para a taxa de dessorção, a taxa de carregamento da armadilha magnéto-óptica e o número máximo de átomos aprisionados em função da potência da luz de dessorção é mostrada graficamente.
Erickson, Christopher Joseph. "Development of a Strontium-87 Ion Interferometer". BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2750.
Texto completoNascimento, Valter Aragão do. "Dinâmica de colisões entre átomos de Rydberg frios". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-13092007-113228/.
Texto completoCollisional processes involving energy transfer have been intensively investigated in samples of cold Rydberg atoms in the last years. Some research groups have interpreted such processes using a many body model; on the other hand our group has explained such processes considering a two body interaction in an ultralong range potential and the atomic motion under the influence of such potential. In this work, we have investigated such atomic collisions involving cold Rydberg atoms, produced in a magneto-optical trap. The time evolution study of the Rydberg states produced by collisions for different atomic densities has shown us that the binary process is dominant in such system. Beyond that, we have shown that the radiation of black body cannot be neglected in these experiments. Finally, we suggest improvements for the semi-classical collissional dynamic model proposed by our group.
Paiva, Rafael Rothganger de. "Investigação do processo de foto-ionização associativa em situações com baixa dimensão". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-19032009-151203/.
Texto completoPhotoassociative ionization (PAI) in a cold sample of sodium atoms was the main subject of our studies as a way to understand the effects of repulsive states and collision dimensions. Two-color PAI experiment were preformed in a magneto-optical trap (MOT) trough the addition of a probe laser beam, the intensity, polarization and frequency of that probe laser were tunable. The shape of the trapped atoms also could be changed. In a spherical shape MOT, we observed a marked change in the PAI rate constant (K) for a definite frequency range, and that change can be attributed to the influence of repulsive molecular states and the a possible formation of an avoided crossing between molecular levels. In atomotron, ring shaped mot, we changed the polarization of the probe beam, and saw that the ratio between K for a polarization parallel to the atoms motion and a perpendicular one is 4. Comparing the K as a function of the intensity between a spherical shaped mot and atomotron showed us a difference in the behavior and the value of the rate constant.
Kondo, Jorge Douglas Massayuki. "Ressonâncias moleculares em estados nP de átomos de Rydberg frios". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-18112010-145903/.
Texto completoIn this work we studied the role of Rydberg atoms interactions in the nP state and the dc electric field dependency of this process. The nP state shows Föster resonances for principal quantum number less than 37. In this resonance process, an atomic pair in nP state changes to a pair nS+(n+1)S. We have performed two time evolution experiments for 32≤n≤36. In the first one we have investigated the NnS population transfer rate for a variable principal quantum number n. In the second we have study the population transfer for a fixed n=33, by varying an electric field. Moreover, we observed the density dependency of the population in the 33S state by varying the nP state atomic density. The results allow us to observe two distinct contributions, a linear contribution related with the black body radiation and a quadratic one connected with two body process. The results agree well with the rate model used to treat the black body radiation.