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Sample records for 85rb atoms trapped

  1. Realization of an 85Rb Atomic Fountain

    An atomic fountain with 85Rb cold atoms is reported. A series of time-of-flight signals is obtained, and the measured temperature of the cold atomic cloud is about 2.4 μK. It will have potential new applications in the precise measurement of fundamental constants and the proof of the Einstein's equivalence principle. (atomic and molecular physics)

  2. Transference of cold 85Rb atoms from a mirror MOT to U-MOT on an external atom chip

    We have designed an atom chip for manipulating cold atoms with magnetic fields generated by electric currents. Electric wires with a U shape for a quadrupole trap and a Z shape for the Ioffe-Pritchard trap were printed on the 26 mm x 26 mm chip. This chip was bonded on a 16 x 16 x 70 mm3 glass cell. The glass cell was for a mirror MOT. 85Rb atoms are magneto optically trapped near the chip's surface (mirror-MOT); then, the trapped atoms are transferred from the mirror-MOT to the U-MOT by gradually decreasing the magnetic field for the mirror-MOT while increasing the current for the U-MOT. A transfer efficiency of 27.1% was measured by comparing the fluorescence from the atoms of U-MOT and the mirror-MOT.

  3. Interspecies collision-induced losses in a dual species 7Li–85Rb magneto-optical trap

    In this article, we report the measurement of collision-induced loss rate coefficients βLi,Rb and βRb,Li, and also discuss means to significantly suppress such collision-induced losses. We first describe our dual-species magneto-optical trap (MOT) that allows us to simultaneously trap ≥5 × 1087Li atoms loaded from a Zeeman slower and ≥2 × 10885Rb atoms loaded from a dispenser. We observe strong interspecies collision-induced losses in the MOTs which dramatically reduce the maximum atom number achievable in the MOTs. We measure the trap loss rate coefficients βLi,Rb and βRb,Li, and, from a study of their dependence on the MOT parameters, determine the cause for the losses observed. Our results provide valuable insights into ultracold collisions between 7Li and 85Rb, guide our efforts to suppress collision-induced losses, and also pave the way for the production of ultracold 7Li85Rb molecules. (paper)

  4. Elastic Scattering between Ultracold 23Na and 85Rb Atoms in the Triplet State

    HU Qiu-Bo; ZHANG Yong-Sheng; SUN Jin-Feng; YU Ke

    2011-01-01

    @@ The elastic scattering Properties between ultracold 23Na and 85Rd atoms for the triplet state(a3∑u+ )are researched.The s-wave scattering lengts of 23Na and 85Rb are calculate by the Numerov ana semtc asstc method with two kinds of interatomic potentials, which are the interpolation potential and Lennard-Jones potential(LJ12,6)by the same phase 4φ Shape resonances appear clearly in the l= 5 partial waves for the a- Lu state.Moreover, the s-wave scattering cross section, total cross section and energy positions of shape resonances are also discussed.%The elastic scattering properties between ultracold 23Na and 85 Rb atoms for the triplet state (a3Σu+ ) are researched. The s-wave scattering lengths of 23Na and 85Rb are calculated by the Numerov and semiclassical method with two kinds of interatomic potentials, which are the interpolation potential and Lennard-Jones potential (LJ12,6) by the same phase φ. Shape resonances appear clearly in the l= 5 partial waves for the a3 Σu+state. Moreover, the s-wave scattering cross section, total cross section and energy positions of shape resonances are also discussed.

  5. Dependence of the 85Rb coherent population trapping resonance characteristic on the pressure of N2 buffer gas

    In order to exploit its potential applications, we experimentally study the dependence of 85Rb-based coherent population trapping (CPT) resonance on N2 buffer gas with 6 vapor cells filled with natural rubidium and N2. The experiments are carried out at different pressures and temperatures, and the results reveal that higher cell temperature makes the resonance more sensitive to N2 pressure. Thus, it is important to choose a proper buffer gas pressure at a given cell temperature. This work provides valuable data for the application of 85Rb CPT resonance with a buffer gas of N2. (geophysics, astronomy, and astrophysics)

  6. Spectral dependence of diffuse light dynamics in ultracold atomic 85Rb

    Balik, S; Sukenik, C I; Havey, M D; Datsuk, V M; Kupriyanov, D V; Sokolov, I M

    2015-01-01

    We report a combined experimental and theoretical simulation of multiply scattered light dynamics in an ultracold gas of 85Rb atoms. Measurements of the spectral dependence of the time-decay of the scattered light intensity, following pulsed excitation with near resonance radiation, reveals that the decay for long times is nearly exponential, with a decay constant that is largely independent of detuning from resonance. Monte Carlo simulations of the multiple scattering process show that, for large detunings, near resonance scattering of Fourier components of the excitation pulse plays a significant role in the effect. This interpretation is supported by the observations, and successful modelling, of beating between Rayleigh scattered light at the excitation carrier frequency with the Fourier components of the excitation pulse that overlap significantly with the atomic resonance.

  7. 85Rb tunable-interaction Bose-Einstein condensate machine

    We describe our experimental setup for creating stable Bose-Einstein condensates (BECs) of 85Rb with tunable interparticle interactions. We use sympathetic cooling with 87Rb in two stages, initially in a tight Ioffe-Pritchard magnetic trap and subsequently in a weak, large-volume, crossed optical dipole trap, using the 155 G Feshbach resonance to manipulate the elastic and inelastic scattering properties of the 85Rb atoms. Typical 85Rb condensates contain 4x104 atoms with a scattering length of a=+200a0. Many aspects of the design presented here could be adapted to other dual-species BEC machines, including those involving degenerate Fermi-Bose mixtures. Our minimalist apparatus is well suited to experiments on dual-species and spinor Rb condensates, and has several simplifications over the 85Rb BEC machine at JILA, which we discuss at the end of this article.

  8. Splitting of N-type optical resonance formed in Λ-system of 85Rb atoms in a strong transverse magnetic field

    N-type narrow-band optical resonance formed in Λ-system of 85Rb atoms has been studied. Even for the case of thin optical cells (micrometer thickness) usage the N-type resonance has a high contrast. Two continuous narrow-band diode laser radiations were used. The peculiarities of N-type resonance splitting to the six components in strong transverse magnetic fields are experimentally and theoretically studied and the evidence of the Paschen-Back regime on the hyperfine structure of 85Rb atoms is observed

  9. Enhanced light-assisted-collision rate via excitation to the long-lived 5S1/2-5D5/2 molecular potential in an 85Rb magneto-optical trap

    We report measurements of a significant increase in the two-body loss rate in an 85Rb magneto-optic trap (MOT) caused by the addition of light resonant with the 5P3/2-to-5D5/2 transition (776 nm) in Rb. Exposure to the additional light resulted in up to a factor of 5 decrease in the steady-state number of atoms in the MOT. This loss is attributed to more than an order of magnitude increase in the light-assisted collision rate brought about by the 776-nm light. By measuring the intensity dependence of the loss rate, the loss channel was identified to be the relatively long-lived 5S1/2-5D5/2 molecular potential.

  10. Two-Photon Atomic Coherence Effect of Transition 5S1/2-5P3/2-4D5/2(4D3/2) of 85Rb atoms

    DING Dong-Sheng; ZHOU Zhi-Yuan; SHI Bao-Sen; ZOU Xu-Bo; GUO Guang-Can

    2012-01-01

    We experimentally observe the counterintuitive absorption peaks in the transition spectra of 5S1/2-5P3/2-4D5/2 and 5S1/2-5.P3/2-4.D3/2 in a hot 85Rb vapor. These spectra are very different from the spectra observed via double resonance optical pumping or electromagnetically induced transparency in the same transitions. These absorption peaks are from electromagnetically induced absorption due to the two-photon atomic coherence effect. We also investigate the relations between these peaks and the powers of the coupling laser and the probe laser experimen tally.%We experimentally observe the counterintuitive absorption peaks in the transition spectra of 5S1/2-5P3/2-4D5/2 and 5S1/2-5P3/2-4D3/2 in a hot 85Rb vapor.These spectra are very different from the spectra observed via double resonance optical pumping or electromagnetically induced transparency in the same transitions.These absorption peaks are from electromagnetically induced absorption due to the two-photon atomic coherence effect.We also investigate the relations between these peaks and the powers of the coupling laser and the probe laser experimentally.

  11. Power and polarization dependences of ultra-narrow electromagnetically induced absorption (EIA) spectra of 85 Rb atoms in degenerate two-level system

    Qureshi, Muhammad Mohsin; Rehman, Hafeez Ur; Noh, Heung-Ryoul; Kim, Jin-Tae

    2016-05-01

    We have investigated ultra-narrow EIA spectral features with respect to variations of polarizations and powers of pump laser beam in a degenerate two-level system of the transition of 85 Rb D2 transition line. Polarizations of the probe laser beam in two separate experiments were fixed at right circular and horizontal linear polarizations, respectively while the polarizations of the pump lasers were varied from initial polarizations same as the probe laser beams to orthogonal to probe polarizations. One homemade laser combined with AOMs was used to the pump and probe laser beams instead of two different lasers to overcome broad linewidths of the homemade lasers. Theoretically, probe absorption coefficients have been calculated from optical Bloch equations of the degenerate two level system prepared by a pump laser beam. In the case of the circular polarization, EIA signal was obtained as expected theoretically although both pump and probe beams have same polarization. The EIA signal become smaller as power increases and polarizations of the pump and probe beams were same. When the polarization of the pump beam was linear polarization, maximum EIA signal was obtained theoretically and experimentally. Experimental EIA spectral shapes with respect to variations of the pump beam polarization shows similar trends as the theoretical results.

  12. Directly Trapping Atoms in a U-Shaped Magneto-Optical Trap Using a Mini Atom Chip

    We experimentally demonstrate the trapping of 85Rb atoms directly on a chip-size U-shaped magneto-optical trap (U-MOT). The trap includes a U-shaped wire on the chip, two bias magnetic field coils and laser beams. The capture volume of the U-MOT is theoretically calculated, and the trap is experimentally realized. With 2 A current applied to the U-shaped wire and 2-Gauss horizontal bias field, more than 2 × 106 atoms are trapped. In contrast with an ordinary mirror-MOT, this U-MOT captures atoms directly from the background, thus the trap size is greatly reduced. Based on this mini trap scheme, it is possible to realize a chip-size atom trap array for quantum information processing. (atomic and molecular physics)

  13. Optical Guiding of Trapped Atoms by a Blue-Detuned Hollow Laser Beam in the Horizontal Direction

    JIANG Kai-Jun; LI Ke; WANG Jin; ZHAN Ming-Sheng

    2005-01-01

    @@ Optical guiding of 85 Rb atoms in a magneto-optical trap (MOT) by a blue-detuned horizontal hollow laser beam is demonstrated experimentally. The guiding efficiency and the velocity distribution of the guided atoms are found to have strong dependence on the detuning of the guiding laser. In particular, the optimum guiding occurs when the blue detuning of the hollow laser beam is approximately equal to the hyperfine structure splitting of the 85Rb ground states, in good agreement with the theoretical analysis based on a three-level model.

  14. A definitive number of atoms on demand: controlling the number of atoms in a-few-atom magneto-optical trap

    Yoon, S; Park, S; Kim, J; Lee, J H; An, K; Yoon, Seokchan; Choi, Youngwoon; Park, Sangbum; Kim, Jaisoon; Lee, Jai-Hyung; An, Kyungwon

    2006-01-01

    A few 85Rb atoms were trapped in a micron-size magneto-optical trap with a high quadrupole magnetic-field gradient and the number of atoms was precisely controlled by suppressing stochastic loading and loss events via real-time feedback on the magnetic field gradient. The measured occupation probability of single atom was as high as 99%. Atoms up to five were also trapped with high occupation probabilities. The present technique could be used to make a deterministic atom source.

  15. Neutral atom traps.

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  16. A dynamic magneto-optical trap for atom chips

    Rushton, Jo; Bateman, James; Himsworth, Matt

    2016-01-01

    We describe a dynamic magneto-optical trap (MOT) suitable for the use with vacuum systems in which optical access is limited to a single window. This technique facilitates the long-standing desire of producing integrated atom chips, many of which are likely to have severely restricted optical access compared with conventional vacuum chambers. This "switching-MOT" relies on the synchronized pulsing of optical and magnetic fields at audio frequencies. The trap's beam geometry is obtained using a planar mirror surface, and does not require a patterned substrate or bulky optics inside the vacuum chamber. Central to the design is a novel magnetic field geometry that requires no external quadrupole or bias coils which leads toward a very compact system. We have implemented the trap for $^{85}$Rb and shown that it is capable of capturing 2 million atoms and directly cooling below the Doppler temperature.

  17. Characteristics of integrated magneto-optical traps for atom chips

    Pollock, S; Laliotis, A; Ramirez-Martinez, F; Hinds, E A

    2011-01-01

    We investigate the operation of pyramidal magneto-optical traps (MOTs) microfabricated in silicon. Measurements of the loading and loss rates give insight into the role of the nearby surface in the MOT dynamics. Studies of the fluorescence versus laser frequency and intensity allow us to develop a simple theory of operation. The number of $^{85}$Rb atoms trapped in the pyramid is approximately $L^6$, where $L \\lesssim 6$ is the size in mm. This follows quite naturally from the relation between capture velocity and size and differs from the $L^{3.6}$ often used to describe larger MOTs. Our results constitute substantial progress towards fully integrated atomic physics experiments and devices.

  18. Collisional cooling of light ions by co-trapped heavy atoms

    Dutta, Sourav; Rangwala, S A

    2015-01-01

    The most generic cooling and thermalization pathway at the lowest temperatures is via elastic collisions. In hybrid ion-atom traps, ion cooling to temperatures where low partial wave collisions dominate require the collisional cooling mechanism to be well understood and controlled. There exists great uncertainty on whether cooling of light ions by heavier neutral atoms is possible. Here we experimentally demonstrate the cooling of light ions by co-trapped heavy atoms for the first time. We show that trapped 39K+ ions are cooled by localized ultracold neutral 85Rb atoms for an ion-atom mass ratio where most theoretical models predict ion heating. We demonstrate, based on detailed numerical simulation of our ion-cooling model, which is in excellent agreement with experiments, that cooling of ions by localized cold atoms is possible for any mass ratio. Our result opens up the possibility of studying quantum collisions and chemistry in trapped atom-ion systems.

  19. Atom trap trace analysis

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O' Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  20. Atomic Coherent Trapping and Properties of Trapped Atom

    YANG Guo-Jian; XIA Li-Xin; XIE Min

    2006-01-01

    Based on the theory of velocity-selective coherent population trapping, we investigate an atom-laser system where a pair of counterpropagating laser fields interact with a three-level atom. The influence of the parametric condition on the properties of the system such as velocity at which the atom is selected to be trapped, time needed for finishing the coherent trapping process, and possible electromagnetically induced transparency of an altrocold atomic medium,etc., is studied.

  1. Photodissociation of trapped Rb$^+_2$ : Implications for hybrid molecular ion-atom trapping

    Jyothi, S; Dutta, Sourav; Allouche, A R; Vexiau, Romain; Dulieu, Olivier; Rangwala, S A

    2016-01-01

    We observe direct photodissociation of trapped $^{85}$Rb$_2^+$ molecular ions in the presence of cooling light for the $^{85}$Rb magneto optical trap (MOT). Vibrationally excited Rb$_{2}^{+}$ ions are created by photoionization of Rb$_{2}$ molecules formed photoassociatively in the rubidium (Rb) MOT and are trapped in a modified spherical Paul trap co-centric with the MOT. The decay rate of the trapped Rb$_{2}^{+}$ ion signal in the presence of the MOT cooling light is measured and agreement with our calculated rates for molecular ion photodissociation is established. The photodissociation mechanism due to the MOT light is expected to be active and therefore universal for all homonuclear diatomic alkali metal molecular ions.

  2. Observation of Deeply-Bound 85 Rb2 Vibrational Levels Using Feshbach Optimized Photoassociation

    Krzyzewski, Sean; Akin, Tom; Dizikes, James; Morrison, Michael; Abraham, Eric

    2016-05-01

    We demonstrate Feshbach optimized photoassociation (FOPA) into the 0g-(5 S1/2 + 5 P1/2) state in 85 Rb2. FOPA uses the enhancement of the amplitude of the initial atomic scattering wave function due to a Feshbach resonance to increase the molecular formation rate from photoassociation. We observe three vibrational levels, v = 127 , 140, and 150, with previously unmeasured binding energies of 256, 154, and 96 cm-1. We measure the frequency, central magnetic field position, and magnetic field width of each Feshbach resonance. Our findings experimentally confirm that this technique can measure vibrational levels lower than those accessible to traditional photoassociative spectroscopy. We present theory concerning the polarization dependence of FOPA for this system, and discuss implications of using this system to measure the time-variation of the electron/proton mass ratio.

  3. Microchip-Based Trapped-Atom Clocks

    Vuletic, Vladan; Leroux, Ian D.; Schleier-Smith, Monika H.

    2011-01-01

    This is a chapter of a recently published book entitled Atom Chips, edited by Jakob Reichel and Vladan Vuletic. The contents of this chapter include: Basic Principles; Atomic-Fountain versus Trapped-Atom Clocks; Optical-Transition Clocks versus Microwave Clocks; Clocks with Magnetically Trapped Atoms--Fundamental Limits and Experimental Demonstrations; Readout in Trapped-Atom Clocks; and Spin Squeezing.

  4. High-Resolution Spectroscopy of Long-Range Molecular States of 85Rb_2

    Carollo, Ryan; Eyler, Edward E.; Bruneau, Yoann; Gould, Phillip; Stwalley, W. C.

    2015-06-01

    We present analysis of low-n long-range molecular Rydberg states in 85Rb_2, based on high-resolution spectra. The weakly bound states are accessed by bound-bound transitions from high-v levels of the a ^3 σ _u^+ state, which are prepared by photoassociation of laser-cooled atoms. Single-photon transitions to target states near the 5s + 7p asymptote are excited by a frequency-doubled pulse-amplified CW laser with a narrow linewidth, under 200 MHz. The long-range portion of the bonding potential is dominated by the elastic scattering interaction of the Rydberg electron of a perturbed 7p atom and a nearby ground-state atom, in much the same manner as trilobite states. We use time of flight to selectively measure molecular ions, which are formed via autoionization. This technique gives a two orders-of-magnitude improvement in linewidth over our previous work, reported in Ref. [1]. We also present calculations of a proposed scheme for STIRAP transfer from the current v''=35 level of the a ^3 σ _u^+ state to the v''=39 level. The long-range states accessible to us are defined in large part by the Franck-Condon factors, which are dominated by the outer lobe of the wavefunction. Thus, choosing a v'' sets R, and determines the Franck-Condon window. The proposed v'' = 39 level has a classical outer turning point at ˜ 72 a_0, and will provide access to higher-n states with longer-range wells. This work is supported by the NSF and AFOSR. [1] M. A. Bellos et al., Phys. Rev. Lett. 111, 053001 (2013)

  5. Spectroscopy of the Double Minimum $3\\,^3 \\Pi_{\\Omega}$ Electronic State of $^{39}$K$^{85}$Rb

    Banerjee, Jayita; Carollo, Ryan; Bellos, Michael; Eyler, Edward E; Gould, Phillip L; Stwalley, William C

    2013-01-01

    We report the observation and analysis of the $3\\,^3\\Pi_{\\Omega}$ double-minimum electronic excited state of $^{39}$K$^{85}$Rb. The spin-orbit components ($0^{+}, 0^{-}, 1$ and 2) of this state are investigated based on potentials developed from the available \\emph{ab initio} potential curves. We have assigned the vibrational levels $v'=2-11$ of the $3\\,^3\\Pi_{1,2}$ potentials and $v'=2-12$ of the $3\\,^3\\Pi_{0^{+/-}}$ potential. We compare our experimental observations of the $3\\,^3\\Pi_{\\Omega}$ state with predictions based on theoretical potentials. The observations are based on resonance enhanced multiphoton ionization (REMPI) of ultracold KRb in vibrational levels $v"=14-25$ of the $a\\,^3\\Sigma^+$ state. These \\emph{a}-state ultracold molecules are formed by photoassociation of ultracold $^{39}$K and $^{85}$Rb atoms to the 5(1) state of KRb followed by spontaneous emission to the \\emph{a} state.

  6. Cold atoms in videotape micro-traps

    Sinclair, C. D. J.; Retter, J. A.; Curtis, E. A.; Hall, B. V.; Llorente Garcia, I.; Eriksson, S.; Sauer, B. E.; Hinds, E. A.

    2005-08-01

    We describe an array of microscopic atom traps formed by a pattern of magnetisation on a piece of videotape. We describe the way in which cold atoms are loaded into one of these micro-traps and how the trapped atom cloud is used to explore the properties of the trap. Evaporative cooling in the micro-trap down to a temperature of 1~μK allows us to probe the smoothness of the trapping potential and reveals some inhomogeneity produced by the magnetic film. We discuss future prospects for atom chips based on microscopic permanent-magnet structures.

  7. Cold atoms in videotape micro-traps

    Sinclair, C D J; Curtis, E A; Hall, B V; Garcia, I L; Eriksson, S; Sauer, B E; Hinds, E A

    2005-01-01

    We describe an array of microscopic atom traps formed by a pattern of magnetisation on a piece of videotape. We describe the way in which cold atoms are loaded into one of these micro-traps and how the trapped atom cloud is used to explore the properties of the trap. Evaporative cooling in the micro-trap down to a temperature of 1 microkelvin allows us to probe the smoothness of the trapping potential and reveals some inhomogeneity produced by the magnetic film. We discuss future prospects for atom chips based on microscopic permanent-magnet structures.

  8. Determination of the hyperfine structure constants of the 87Rb and 85Rb 4 D5 /2 state and the isotope hyperfine anomaly

    Wang, Jie; Liu, Huifeng; Yang, Guang; Yang, Baodong; Wang, Junmin

    2014-11-01

    The hyperfine structure (hfs) splittings of the 4 D5 /2 state for two isotopes of 87Rb and 85Rb atoms are measured based on double-resonance optical pumping spectra in a 5 S1 /2-5 P3 /2-4 D5 /2 ladder-type atomic system. The frequency calibration is performed by employing a wideband fiber-pigtailed phase-type electro-optic modulator together with a Fabry-Pérot cavity to cancel the error arising from nonlinear frequency scanning. The hfs magnetic dipole constant A of the 4 D5 /2 state is determined to be -16.801 ± 0.005 MHz for 87Rb and -4.978 ± 0.004 MHz for 85Rb . The hfs electric quadrupole constant B of the 4 D5 /2 state is determined to be 3.645 ± 0.030 MHz for 87Rb and 6.560 ± 0.052 MHz for 85Rb . The values of A and B for the 87Rb4 D5 /2 state are twice as accurate as previous work with thermal atoms using a femtosecond laser comb and the values of A and B for the 85Rb4 D5 /2 state are 3 times and 25 times more accurate than previous work in laser-cooled atoms using Fabry-Pérot interferometer, respectively. According to this high precision of the hfs constants and the previously measured nuclear g factors of the two isotopes, the value of the d -electron hyperfine anomaly 87Δ85(4 D5 /2 ) is derived to be -0.0041 ± 0.0009.

  9. Characterizing optical dipole trap via fluorescence of trapped cesium atoms

    LIU; Tao; GENG; Tao; YAN; Shubin; LI; Gang; ZHANG; Jing; WANG; Junmin; PENG; Kunchi; ZHANG; Tiancai

    2006-01-01

    Optical dipole trap (ODT) is becoming an important tool of manipulating neutral atoms. In this paper ODT is realized with a far-off resonant laser beam strongly focused in the magneto-optical trap (MOT) of cesium atoms. The light shift is measured by simply monitoring the fluorescence of the atoms in the magneto-optical trap and the optical dipole trap simultaneously. The advantages of our experimental scheme are discussed, and the effect of the beam waist and power on the potential of dipole trap as well as heating rate is analyzed.

  10. The determination of potential energy curve and dipole moment of the (5)0+ electronic state of 85Rb133Cs molecule by high resolution photoassociation spectroscopy

    We present the formation of ultracold 85Rb133Cs molecules in the (5)0+ electronic state by photoassociation and their detection via resonance-enhanced two-photon ionization. Up to v = 47 vibrational levels including the lowest v = 0 vibrational and lowest J = 0 levels are identified with rotationally resolved high resolution photoassociation spectra. Precise Dunham coefficients are determined for the (5)0+ state with high accuracy, then the Rydberg-Klein-Rees potential energy curve is derived. The electric dipole moments with respect to the vibrational numbers of the (5)0+ electronic state of 85Rb133Cs molecule are also measured in the range between 1.9 and 4.8 D. These comprehensive studies on previously unobserved rovibrational levels of the (5)0+ state are helpful to understand the molecular structure and discover suitable transition pathways for transferring ultracold atoms to deeply bound rovibrational levels of the electronic ground state

  11. Laser cooling and trapping of atoms

    The basic ideas of laser cooling and atom trapping will be discussed. These techniques have applications in spectroscopy, metrology, nuclear physics, biophysics, geophysics, and polymer science. (author)

  12. Magnetic Trapping of Cold Bromine Atoms

    Rennick, C J; Doherty, W G; Softley, T P

    2014-01-01

    Magnetic trapping of bromine atoms at temperatures in the milliKelvin regime is demonstrated for the first time. The atoms are produced by photodissociation of Br$_2$ molecules in a molecular beam. The lab-frame velocity of Br atoms is controlled by the wavelength and polarization of the photodissociation laser. Careful selection of the wavelength results in one of the pair of atoms having sufficient velocity to exactly cancel that of the parent molecule, and it remains stationary in the lab frame. A trap is formed at the null point between two opposing neodymium permanent magnets. Dissociation of molecules at the field minimum results in the slowest fraction of photofragments remaining trapped. After the ballistic escape of the fastest atoms, the trapped slow atoms are only lost by elastic collisions with the chamber background gas. The measured loss rate is consistent with estimates of the total cross section for only those collisions transferring sufficient kinetic energy to overcome the trapping potential...

  13. Trapping atoms on a transparent permanent-magnet atom chip

    Shevchenko, A; Jaakkola, A; Kaivola, M; Lindvall, T; Pfau, T; Tittonen, I

    2006-01-01

    We describe experiments on trapping of atoms in microscopic magneto-optical traps on an optically transparent permanent-magnet atom chip. The chip is made of magnetically hard ferrite-garnet material deposited on a dielectric substrate. The confining magnetic fields are produced by miniature magnetized patterns recorded in the film by magneto-optical techniques. We trap Rb atoms on these structures by applying three crossed pairs of counter-propagating laser beams in the conventional magneto-optical trapping (MOT) geometry. We demonstrate the flexibility of the concept in creation and in-situ modification of the trapping geometries through several experiments.

  14. Laser cooling and trapping of atoms

    Townsend Christopher G.

    1995-01-01

    A detailed experimental and theoretical investigation of a magneto-optical trap for caesium atoms is presented. Particular emphasis has been placed on achieving high spatial number densities and low temperatures. Optimizing both of these together enables efficient evaporative cooling from a conservative trap, a procedure which has recently led to the first observations of Bose-Einstein condensation in a dilute atomic vapour. The behaviour of a magneto-optical trap is nomina...

  15. Laser trapping of 21Na atoms

    This thesis describes an experiment in which about four thousand radioactive 21Na (tl/2 = 22 sec) atoms were trapped in a magneto-optical trap with laser beams. Trapped 21Na atoms can be used as a beta source in a precision measurement of the beta-asymmetry parameter of the decay of 21Na → 21Ne + Β+ + ve, which is a promising way to search for an anomalous right-handed current coupling in charged weak interactions. Although the number o trapped atoms that we have achieved is still about two orders of magnitude lower than what is needed to conduct a measurement of the beta-asymmetry parameter at 1% of precision level, the result of this experiment proved the feasibility of trapping short-lived radioactive atoms. In this experiment, 21Na atoms were produced by bombarding 24Mg with protons of 25 MeV at the 88 in. Cyclotron of Lawrence Berkeley Laboratory. A few recently developed techniques of laser manipulation of neutral atoms were applied in this experiment. The 21Na atoms emerging from a heated oven were first transversely cooled. As a result, the on-axis atomic beam intensity was increased by a factor of 16. The atoms in the beam were then slowed down from thermal speed by applying Zeeman-tuned slowing technique, and subsequently loaded into a magneto-optical trap at the end of the slowing path. The last two chapters of this thesis present two studies on the magneto-optical trap of sodium atoms. In particular, the mechanisms of magneto-optical traps at various laser frequencies and the collisional loss mechanisms of these traps were examined

  16. An Atom Trap Relying on Optical Pumping

    Bouyer, P; Dahan, M B; Michaud, A; Salomon, C; Dalibard, J

    1994-01-01

    We have investigated a new radiation pressure trap which relies on optical pumping and does not require any magnetic field. It employs six circularly polarized divergent beams and works on the red of a $J_{g} \\longrightarrow J_{e} = J_{g} + 1$ atomic transition with $J_{g} \\geq 1/2$. We have demonstrated this trap with cesium atoms from a vapour cell using the 852 nm $J_{g} = 4 \\longrightarrow J_{e} = 5$ resonance transition. The trap contained up to $3 \\cdot 10^{7}$ atoms in a cloud of $1/\\sqrt{e}$ radius of 330 $\\mu$m.

  17. A Bose-condensed, simultaneous dual-species Mach–Zehnder atom interferometer

    This paper presents the first realization of a simultaneous 87Rb–85Rb Mach–Zehnder atom interferometer with Bose-condensed atoms. A number of ambitious proposals for precise terrestrial and space based tests of the weak equivalence principle rely on such a system. This implementation utilizes hybrid magnetic-optical trapping to produce spatially overlapped condensates with a repetition rate of 20 s. A horizontal optical waveguide with co-linear Bragg beamsplitters and mirrors is used to simultaneously address both isotopes in the interferometer. We observe a non–linear phase shift on a non-interacting 85Rb interferometer as a function of interferometer time, T, which we show arises from inter-isotope scattering with the co-incident 85Rb interferometer. A discussion of implications for future experiments is given. (paper)

  18. Enhanced Magnetic Trap Loading for Atomic Strontium

    Barker, D S; Pisenti, N C; Campbell, G K

    2015-01-01

    We report on a technique to improve the continuous loading of atomic strontium into a magnetic trap from a Magneto-Optical Trap (MOT). This is achieved by adding a depumping laser tuned to the 3P1 to 3S1 (688-nm) transition. The depumping laser increases atom number in the magnetic trap and subsequent cooling stages by up to 65 % for the bosonic isotopes and up to 30 % for the fermionic isotope of strontium. We optimize this trap loading strategy with respect to the 688-nm laser detuning, intensity, and beam size. To understand the results, we develop a one-dimensional rate equation model of the system, which is in good agreement with the data. We discuss the use of other transitions in strontium for accelerated trap loading and the application of the technique to other alkaline-earth-like atoms.

  19. Nanostructured optical nanofibres for atom trapping

    Daly, Mark; Phelan, Ciarán; Deasy, Kieran; Chormaic, Síle Nic

    2013-01-01

    We propose an optical dipole trap for cold neutral atoms based on the electric field produced from the evanescent fields in a hollow rectangular slot cut through an optical nanofibre. In particular, we discuss the trap performance in relation to laser-cooled rubidium atoms and show that a far off-resonance, blue-detuned field combined with the attractive surface-atom interaction potential from the dielectric material forms a stable trapping configuration. With the addition of a red-detuned field, we demonstrate how three dimensional confinement of the atoms at a distance of 140 - 200 nm from the fibre surface within the slot can be accomplished. This scheme facilitates optical coupling between the atoms and the nanofibre that could be exploited for quantum communication schemes using ensembles of laser-cooled atoms.

  20. Suppression of Dephasing of Optically Trapped Atoms

    Andersen, M F; Grünzweig, T; Davidson, N

    2003-01-01

    Ultra-cold atoms trapped in an optical dipole trap and prepared in a coherent superposition of their hyperfine ground states, decohere as they interact with their environment. We demonstrate than the loss in coherence in an "echo" experiment, which is caused by mechanisms such as Rayleigh scattering, can be suppressed by the use of a new pulse sequence. We also show that the coherence time is then limited by mixing to other vibrational levels in the trap and by the finite lifetime of the internal quantum states of the atoms.

  1. Collisional trap losses of cold, magnetically-trapped Br atoms

    Lam, J; Softley, T P

    2014-01-01

    Near-threshold photodissociation of Br$_2$ from a supersonic beam produces slow bromine atoms that are trapped in the magnetic field minimum formed between two opposing permanent magnets. Here, we quantify the dominant trap loss rate due to collisions with two sources of residual gas: the background limited by the vacuum chamber base pressure, and the carrier gas during the supersonic gas pulse. The loss rate due to collisions with residual Ar in the background follows pseudo first-order kinetics, and the bimolecular rate coefficient for collisional loss from the trap is determined by measurement of this rate as a function of the background Ar pressure. This rate coefficient is smaller than the total elastic collision rate coefficient, as it only samples those collisions that lead to trap loss, and is determined to be $\\langle\

  2. Formation of ultracold 7Li85Rb molecules in the lowest triplet electronic state by photoassociation and their detection by ionization spectroscopy

    We report the formation of ultracold 7Li85Rb molecules in the a3Σ+ electronic state by photoassociation (PA) and their detection via resonantly enhanced multiphoton ionization (REMPI). With our dual-species Li and Rb magneto-optical trap apparatus, we detect PA resonances with binding energies up to ∼62 cm−1 below the 7Li 2s 2S1/2 + 85Rb 5p 2P1/2 asymptote. In addition, we use REMPI spectroscopy to probe the a3Σ+ state and excited electronic 33Π and 43Σ+ states and identify a3Σ+ (v″ = 7–13), 33Π (vΠ′ = 0–10), and 43Σ+ (vΣ′ = 0–5) vibrational levels. Our line assignments agree well with ab initio calculations. These preliminary spectroscopic studies on previously unobserved electronic states are crucial to discovering transition pathways for transferring ultracold LiRb molecules created via PA to deeply bound rovibrational levels of the electronic ground state

  3. Formation of ultracold (7)Li(85)Rb molecules in the lowest triplet electronic state by photoassociation and their detection by ionization spectroscopy.

    Altaf, Adeel; Dutta, Sourav; Lorenz, John; Pérez-Ríos, Jesús; Chen, Yong P; Elliott, D S

    2015-03-21

    We report the formation of ultracold (7)Li(85)Rb molecules in the a(3)Σ(+) electronic state by photoassociation (PA) and their detection via resonantly enhanced multiphoton ionization (REMPI). With our dual-species Li and Rb magneto-optical trap apparatus, we detect PA resonances with binding energies up to ∼62 cm(-1) below the (7)Li 2s (2)S1/2 + (85)Rb 5p (2)P1/2 asymptote. In addition, we use REMPI spectroscopy to probe the a(3)Σ(+) state and excited electronic 3(3)Π and 4(3)Σ(+) states and identify a(3)Σ(+) (v″ = 7-13), 3(3)Π (vΠ' = 0-10), and 4(3)Σ(+) (vΣ' = 0-5) vibrational levels. Our line assignments agree well with ab initio calculations. These preliminary spectroscopic studies on previously unobserved electronic states are crucial to discovering transition pathways for transferring ultracold LiRb molecules created via PA to deeply bound rovibrational levels of the electronic ground state. PMID:25796252

  4. Tightly confined atoms in optical dipole traps

    This thesis reports on the design and setup of a new atom trap apparatus, which is developed to confine few rubidium atoms in ultrahigh vacuum and make them available for controlled manipulations. To maintain low background pressure, atoms of a vapour cell are transferred into a cold atomic beam by laser cooling techniques, and accumulated by a magneto-optic trap (MOT) in a separate part of the vacuum system. The laser cooled atoms are then transferred into dipole traps made of focused far-off-resonant laser fields in single- or crossed-beam geometry, which are superimposed with the center of the MOT. Gaussian as well as hollow Laguerre-Gaussian (LG$(01)$) beam profiles are used with red-detuned or blue-detuned light, respectively. Microfabricated dielectric phase objects allow efficient and robust mode conversion of Gaussian into Laguerre-Gaussian laser beams. Trap geometries can easily be changed due to the highly flexible experimental setup. The dipole trap laser beams are focused to below 10 microns at a power of several hundred milliwatts. Typical trap parameters, at a detuning of several ten nanometers from the atomic resonance, are trag depths of few millikelvin, trap frequencies near 30-kHz, trap light scattering rates of few hundred photons per atom and second, and lifetimes of several seconds. The number of dipole-trapped atoms ranges from more than ten thousand to below ten. The dipole-trapped atoms are detected either by a photon counting system with very efficient straylight discrimination, or by recapture into the MOT, which is imaged onto a sensitive photodiode and a CCD-camera. Due to the strong AC-Stark shift imposed by the high intensity trapping light, energy-selective resonant excitation and detection of the atoms is possible. The measured energy distribution is consistent with a harmonic potential shape and allows the determination of temperatures and heating rates. In first measurements, the thermal energy is found to be about 10 % of the trap

  5. Single photon from a single trapped atom

    Full text: A quantum treatment of the interaction between atoms and light usually begins with the simplest model system: a two-level atom interacting with a monochromatic light wave. Here we demonstrate an elegant experimental realization of this system using an optically trapped single rubidium atom illuminated by resonant light pulses. We observe Rabi oscillations, and show that this system can be used as a highly efficient triggered source of single photons with a well-defined polarisation. In contrast to other sources based on neutral atoms and trapped ions, no optical cavity is required. We achieved a flux of single photons of about 104 s-1 at the detector, and observe complete antibunching. This source has potential applications for distributed atom-atom entanglement using single photons. (author)

  6. Atomic hydrogen in a magnetic trap

    This thesis describes the construction and application of a static magnetic trap for atomic hydrogen. It is demonstrated that densities of up to 3*1014 cm-3 at temperatures of 80 to 200 mK can be achieved with a technically simple method of filling the trap. Double polarization is shown to occur spontaneously in the trapped gas, and the dipolar relaxation rate and its field dependance are measured confirming theoretical predictions. These results show that atomic hydrogen is a promising material for the achievement of Bose-Einstein condensation, provided that apart from the present method of cooling the gas, which is shown to impose a lower limit on the temperature, another cooling mechanism is supplied to reach lower temperatures. The density reached was two orders of magnitude higher than that of trapping experiments done at MIT where the technique of evaporate cooling was used to reach a temperature lower than 3 mK. (author). 138 refs.; 27 figs

  7. Virial theorems for trapped cold atoms

    Werner, Félix

    2008-01-01

    A few small corrections We present a general virial theorem for quantum particles with arbitrary zero-range or finite-range interactions in an arbitrary external potential. We deduce virial theorems for several situations relevant to trapped cold atoms: zero-range interactions with and without Efimov effect, hard spheres, narrow Feshbach resonances, and finite-range interactions. If the scattering length $a$ is varied adiabatically in the BEC-BCS crossover, we find that the trapping potent...

  8. Introduction to light forces, atom cooling, and atom trapping

    Savage, Craig

    1995-01-01

    This paper introduces and reviews light forces, atom cooling and atom trapping. The emphasis is on the physics of the basic processes. In discussing conservative forces the semi-classical dressed states are used rather than the usual quantized field dressed states.

  9. Photoassociation and ionization spectroscopy of ultracold $^{7}$Li$^{85}$Rb molecules

    Altaf, Adeel; Lorenz, John; Pérez-Ríos, Jesús; Chen, Yong P; Elliott, D S

    2014-01-01

    We report spectroscopic studies of ultracold $^{7}$Li$^{85}$Rb molecules using multiphoton ionization detection. With our dual-species Li and Rb MOT apparatus, we create ultracold LiRb molecules via photoassociation (PA), and explore new PA resonances, with binding energies up to ~62 cm^{-1}. Furthermore, we measure the resonantly enhanced multiphoton ionization (REMPI) spectra as a probe of ground and excited state vibrational levels. We identify vibrational levels of the $a^{3}\\Sigma^{+} (v" = 7 - 13)$, $3^{3} \\Pi (v'_{\\Pi} = 0 - 10)$ and $4^{3} \\Sigma^{+} (v'_{\\Sigma} = 0 - 5)$ electronic states. Our line assignments agree well with ab initio calculations. These spectroscopic studies are crucial to discovering transition pathways for transferring ultracold LiRb molecules created via PA to deeply bound rovibrational levels of the electronic ground state.

  10. Suppression of the stellar enhancement factor and the reaction 85Rb(p,n)85Sr

    Rauscher, T; Gyürky, Gy; Simon, A; Fülöp, Z; Somorjai, E

    2009-01-01

    It is shown that a Coulomb suppression of the stellar enhancement factor occurs in many endothermic reactions at and far from stability. Contrary to common assumptions, reaction measurements for astrophysics with minimal impact of stellar enhancement should be preferably performed for those reactions instead of their reverses, despite of their negative reaction Q-value. As a demonstration, the cross section of the astrophysically relevant 85Rb(p,n)85Sr reaction has been measured by activation between 2.16<=E_{c.m.}<= 3.96 MeV and the astrophysical reaction rates at p-process temperatures for (p,n) as well as (n,p) are directly inferred from the data. Additionally, our results confirm a previously derived modification of a global optical proton potential. The presented arguments are also relevant for other alpha- and proton-induced reactions in the p-, rp-, and nu-p-processes.

  11. Anisotropic optical trapping of ultracold erbium atoms

    Dulieu, Olivier; Lepers, Maxence; Wyart, Jean-Francois

    2014-05-01

    We calculate the complex dynamic dipole polarizability of ground-state erbium, a rare-earth atom that was recently Bose-condensed. This quantity determines the trapping conditions of cold atoms in an optical trap. The polarizability is calculated with the sum-over-state formula inherent to second-order perturbation theory. The summation is performed on transition energies and transition dipole moments from ground-state erbium, which are computed using the Racah-Slater least-square fitting procedure provided by the Cowan codes. This allows us to predict several yet unobserved energy levels in the range 25000-31000 cm-1 above the ground state. Regarding the trapping potential, we find that ground-state erbium essentially behaves like a spherically-symmetric atom, in spite of its large electronic angular momentum. We find a mostly isotropic van der Waals interaction between two ground-state erbium atoms, with a coefficient C6iso= 1760 a.u.. On the contrary, the photon-scattering rate is strongly anisotropic with respect to the polarization of the trapping light. also at LERMA, UMR8112, Observatoire de Paris-Meudon, Univ. Pierre et Marie Curie, Meudon, France.

  12. Quantum state control of trapped Holmium atoms

    Hostetter, James; Yip, Christopher; Milner, William; Booth, Donald; Collett, Jeffrey; Saffman, Mark

    2016-05-01

    Neutral Holmium with its large number of hyperfine ground states provides a promising approach for collective encoding of a multi-qubit register. A prerequisite for collective encoding is the ability to prepare different states in the 128 state hyperfine ground manifold. We report progress towards optical pumping and control of the hyperfine Zeeman state of trapped Ho atoms. Atoms are transferred from a 410.5 nm MOT into a 455 nm optical dipole trap. The atoms can be optically pumped using light driving the ground 6s2 , F = 11 to 6 s 6 p ,F' = 11 transition together with a F = 10 to F' = 11 repumper. Microwave fields are then used to drive transitions to hyperfine levels with 4 <= F <= 11 . Work supported by NSF award PHY-1404357.

  13. Magneto-Optical Trapping of Holmium Atoms

    Miao, J; Stratis, G; Saffman, M

    2014-01-01

    We demonstrate sub-Doppler laser cooling and magneto-optical trapping of the rare earth element Holmium. Atoms are loaded from an atomic beam source and captured in six-beam $\\sigma_+ - \\sigma_-$ molasses using a strong $J=15/2 \\leftrightarrow J=17/2$ cycling transition at $\\lambda=410.5~\\rm nm$. Due to the small difference in hyperfine splittings and Land\\'e $g$-factors in the lower and upper levels of the cooling transition the MOT is self-repumped without additional repump light, and deep sub-Doppler cooling is achieved with the magnetic trap turned on. We measure the leakage out of the cycling transition to metastable states and find a branching ratio $\\sim 10^{-5}$ which is adequate for state resolved measurements on hyperfine encoded qubits.

  14. Continuous magnetic trapping of laser cooled atoms

    The authors present here initial results of the deceleration of a thermal atomic beam from -- 1000 to -- 100 m/s. The experiment was conducted in the 1.4-m long vertical superconducting solenoid which produced the slowing field. The fluorescence of the slowed atomic beam has been studied as a function of laser frequency. Figure 2 is a 12-GHz scan showing the fluorescence at a position 150 cm from the beginning of the solenoid. The wide peak corresponds to unslowed atoms with generally the initial velocity distribution. The second, narrower, peak corresponds to slowed atoms with a velocity of -- 150 m/s. Similar spectra have been obtained for various positions along the magnetic slower and trap. These data should allow better understanding of the cooling process and will be compared to computer models

  15. Two dipolar atoms in a harmonic trap

    Ołdziejewski, Rafał; Górecki, Wojciech; Rzążewski, Kazimierz

    2016-05-01

    Two identical dipolar atoms moving in a harmonic trap without an external magnetic field are investigated. Using the algebra of angular momentum we reduce the problem to a simple numerics. We show that the internal spin-spin interactions between the atoms couple to the orbital angular momentum causing an analogue of the Einstein-de Haas effect. We show a possibility of adiabatically pumping our system from the s-wave to the d-wave relative motion. The effective spin-orbit coupling occurs at anti-crossings of the energy levels.

  16. Tunneling of trapped-atom Bose condensates

    Subodh R Shenoy

    2002-02-01

    We obtain the dynamics in number and phase difference, for Bose condensates that tunnel between two wells of a double-well atomic trap, using the (nonlinear) Gross–Pitaevskii equation. The dynamical equations are of the canonical form for the two conjugate variables, and the Hamiltonian corresponds to that of a momentum-shortened pendulum, supporting a richer set of tunneling oscillation modes than for a superconductor Josephson junction, that has a fixed-length pendulum as a mechanical model. Novel modes include ‘inverted pendulum’ oscillations with an average angle of ; and oscillations about a self-maintained population imbalance that we term ‘macroscopic quantum self-trapping’. Other systems with this phase-number nonlinear dynamics include two-component (interconverting) condensates in a single harmonic trap, and He3B superfluids in two containers connected by micropores.

  17. Anisotropic optical trapping of ultracold erbium atoms

    Lepers, Maxence; Dulieu, Olivier; --,

    2013-01-01

    Ultracold atoms confined in a dipole trap are submitted to a potential whose depth is proportional to the real part of their dynamic dipole polarizability. The atoms also experience photon scattering whose rate is proportional to the imaginary part of their dynamic dipole polarizability. In this article we calculate the complex dynamic dipole polarizability of ground-state erbium, a rare-earth atom that was recently Bose-condensed. The polarizability is calculated with the sum-over-state formula inherent to second-order perturbation theory. The summation is performed on transition energies and transition dipole moments from ground-state erbium, which are computed using the Racah-Slater least-square fitting procedure provided by the Cowan codes. This allows us to predict 9 unobserved odd-parity energy levels of total angular momentum J=5, 6 and 7, in the range 25000-31000 cm-1 above the ground state. Regarding the trapping potential, we find that ground-state erbium essentially behaves like a spherically-symme...

  18. The influence of optical molasses in loading a shallow optical trap

    Hamilton, Mathew S.; Gorges, Anthony R.; Roberts, Jacob L.

    2008-01-01

    We have examined loading of 85Rb atoms into a shallow Far-Off-Resonance Trap (FORT) from an optical molasses and compared it to loading from a Magneto-Optical Trap (MOT). We found that substantially more atoms could be loaded into the FORT via an optical molasses as compared to loading from the MOT alone. To determine why this was the case, we measured the rate of atoms loaded into the FORT and the losses from the FORT during the loading process. For both MOT and molasses loading, we examined...

  19. Combined ion and atom trap for low temperature ion-atom physics

    Ravi, K.; LEE, Seunghyun; Sharma, Arijit; Werth, G.; Rangwala, S. A.

    2010-01-01

    We report an experimental apparatus and technique which simultaneously traps ions and cold atoms with spatial overlap. Such an apparatus is motivated by the study of ion-atom processes at temperatures ranging from hot to ultra-cold. This area is a largely unexplored domain of physics with cold trapped atoms. In this article we discuss the general design considerations for combining these two traps and present our experimental setup. The ion trap and atom traps are characterized independently ...

  20. Cold atom-ion experiments in hybrid traps

    Härter, Arne; Denschlag, Johannes Hecker

    2013-01-01

    In the last 5 years, a novel field of physics and chemistry has developed in which cold trapped ions and ultracold atomic gases are brought into contact with each other. Combining ion traps with traps for neutral atoms yields a variety of new possibilities for research and experiments. These range from studies of cold atom-ion collisions and atom-ion chemistry to applications in quantum information science and condensed matter related research. In this article we give a brief introduction int...

  1. Holographic generation of micro-trap arrays for single atoms

    Bergamini, S; Jones, M; Jacubowiez, L; Browaeys, A; Grangier, P; Bergamini, Silvia; Darquie, Benoit; Jones, Matt; Jacubowiez, Lionel; Browaeys, Antoine; Grangier, Philippe

    2004-01-01

    We have generated multiple micron-sized optical dipole traps for neutral atoms using holographic techniques with a programmable liquid crystal spatial light modulator. The setup allows the storing of a single atom per trap, and the addressing and manipulation of individual trapping sites.

  2. Shaking-induced dynamics of cold atoms in magnetic traps

    García, I Llorente; Sinclair, C D J; Curtis, E A; Tachikawa, M; Hudson, J J; Hinds, E A

    2013-01-01

    We describe an experiment in which cold rubidium atoms, confined in an elongated magnetic trap, are excited by transverse oscillation of the trap centre. The temperature after excitation exhibits resonance as a function of the driving frequency. We measure these resonances at several different trap frequencies. In order to interpret the experiments, we develop a simple model that incorporates both collisions between atoms and the anharmonicity of the real three-dimensional trapping potential. As well as providing a precise connection between the transverse harmonic oscillation frequency and the temperature resonance frequency, this model gives insight into the heating and loss mechanisms, and into the dynamics of driven clouds of cold trapped atoms.

  3. Circular magneto-optical trap for neutral atoms

    Morinaga, Makoto

    2005-01-01

    We propose and experimentally demonstrate a novel scheme to magneto-optically trap neutral atoms in a ring shaped trap that can be used to transfer atoms into a circular magnetic trap with high density. This inturn enables to evaporatively cool atoms and study the behaviour of ultra cold gases in a periodic 2-dimensional potential. The circular magneto-optical trap itself is also of interest to investigate the properties of magneto-optical trap of deformed shape, such as reduction of photon-r...

  4. Doppler cooling of an optically dense cloud of trapped atoms

    Schmidt, P O; Werner, J; Binhammer, T; Görlitz, A; Pfau, T; Schmidt, Piet O.; Hensler, Sven; Binhammer, Thomas; G\\"{o}rlitz, Axel; Pfau, Tilman

    2002-01-01

    We have studied a general technique for laser cooling a cloud of polarized trapped atoms down to the Doppler temperature. A one-dimensional optical molasses using polarized light cools the axial motional degree of freedom of the atoms in the trap. Cooling of the radial degrees of freedom can be modelled by reabsorption of scattered photons in the optically dense cloud. We present experimental results for a cloud of chromium atoms in a magnetic trap. A simple model based on rate equations shows quantitative agreement with the experimental results. This scheme allows us to readily prepare a dense cloud of atoms in a magnetic trap with ideal starting conditions for evaporative cooling.

  5. Cooling and trapping neutral atoms with radiative forces

    Techniques to slow and trap neutral atoms at high densities with radiative forces are discussed in this review articles. Among several methods of laser cooling, it is emphasized Zeeman Tuning of the electronic levels and frequency-sweeping techniques. Trapping of neutral atoms and recent results obtained in light and magnetic traps are discussed. Techniques to further cool atoms inside traps are presented and the future of laser cooling of neutral atoms by means of radiation pressure is discussed. (A.C.A.S.)

  6. Trapping atoms in the vacuum field of a cavity

    Schön, C

    2003-01-01

    The aim of this work is to find ways to trap an atom in a cavity. In contrast to other approaches we propose a method where the cavity is basically in the vacuum state and the atom in the ground state. The idea is to induce a spatial dependent AC Stark shift by irradiating the atom with a weak laser field, so that the atom experiences a trapping force. The main feature of our setup is that dissipation can be strongly suppressed. We estimate the lifetime of the atom as well as the trapping potential parameters and compare our estimations with numerical simulations.

  7. A toroidal trap for cold {}^{87}{Rb} atoms using an rf-dressed quadrupole trap

    Chakraborty, A.; Mishra, S. R.; Ram, S. P.; Tiwari, S. K.; Rawat, H. S.

    2016-04-01

    We demonstrate the trapping of cold {}87{Rb} atoms in a toroidal geometry using a radio frequency (rf) dressed quadrupole magnetic trap formed by superposing a strong rf-field on a quadrupole trap. This rf-dressed quadrupole trap has the minimum potential away from the quadrupole trap centre on a circular path which facilitates trapping in toroidal geometry. In these experiments, the laser cooled atoms were first trapped in a quadrupole trap, then cooled evaporatively using a weak rf-field, and finally trapped in an rf-dressed quadrupole trap. The radius of the toroid could be varied by varying the frequency of the dressing rf-field. It has also been demonstrated that a single rf source and an antenna can be used for the rf-evaporative cooling as well as for the rf-dressing of atoms. The atoms trapped in the toroidal trap may have applications in the realization of an atom gyroscope as well as in studying the quantum gases in low dimensions.

  8. A toroidal trap for the cold $^{87}Rb$ atoms using a rf-dressed quadrupole trap

    Chakraborty, A; Ram, S P; Tiwari, S K; Rawat, H S

    2015-01-01

    We demonstrate the trapping of cold $^{87}Rb$ atoms in a toroidal geometry using a rf-dressed quadrupole magnetic trap formed by superposing a strong radio frequency (rf) field on a quadrupole trap. This rf-dressed quadrupole trap has minimum of the potential away from the quadrupole trap centre on a circular path which facilitates the trapping in the toroidal geometry. In the experiments, the laser cooled atoms were first trapped in the quadrupole trap, then cooled evaporatively using a weak rf-field, and finally trapped in the rf-dressed quadrupole trap. The radius of the toroid could be varied by varying the frequency of the dressing rf-field. It has also been demonstrated that a single rf source and an antenna can be used for the rf-evaporative cooling as well as for rf-dressing of atoms. The atoms trapped in the toroidal trap may have applications in realization of an atom gyroscope as well as in studying the quantum gases in low dimensions.

  9. Studies on cold atoms trapped in a Quasi-Electrostatic optical dipole trap

    We discuss the results of measurements of the temperature and density distribution of cold Rubidium atoms trapped and cooled in an optical dipole trap formed by focussed CO2 laser beams at a wavelength of 10.6 μm from a cold, collimated and intense atomic beam of flux 2 x 1010 atoms/s produced using an elongated 2D+MOT. A large number of rubidium atoms (≥ 1010) were trapped in the MOT and the number density of atoms were further increased by making a temporal dark MOT to prevent density-limiting processes like photon rescattering by atoms at the trap centre. Subsequently, between 107 to 108 cold atoms at a temperature below 30 μK were transferred into a Quasi-Electrostatic trap (QUEST) formed by focussed CO2 laser beams at the MOT centre. Both single beam and crossed dual beam dipole traps were studied with a total output power of 50 W from the CO2 laser with focal spot sizes less than 100 microns. Various measurements were done on the cold atoms trapped in the dipole trap. The total atom number in the dipole trap and the spatial atom number density distribution in the trap was measured by absorption imaging technique. The temperature was determined from time-of-flight (TOF) data as well as from the absorption images after ballistic expansion of the atom cloud released from the dipole trap. The results from measurements are used to maximize the initial phase-space density prior to forced evaporative cooling to produce a Bose-Einstein Condensate

  10. Bichromatic State-insensitive Trapping of Caesium Atoms

    Metbulut, M. M.; Renzoni, F.

    2015-01-01

    State-insensitive dipole trapping of multilevel atoms can be achieved by an appropriate choice of the wavelength of the trapping laser, so that the interaction with the different transitions results in equal AC Stark shifts for the ground and excited states of interest. However this approach is severely limited by the availability of coherent sources at the required wavelength and of appropriate power. This work investigates state-insensitive trapping of caesium atoms for which the required w...

  11. A metastable helium trap for atomic collision physics

    Full text: Metastable helium in the 23S state is an important species for atom optics and atomic collision physics. Because of its large internal energy (20eV), long lifetime (∼8000s) and large collision cross section for a range of processes, metastable helium plays an important role in atmospheric physics, plasma discharges and gas laser physics. We have embarked on a program of studies on atom-atom and electron-atom collision processes involving cold metastable helium. We confine metastable helium atoms in a magneto-optic trap (MOT), which is loaded by a transversely collimated, slowed and 2-D focussed atomic beam. We employ diode laser tuned to the 1083 nm (23S1 - 23P21) transition to generate laser cooling forces in both the loading beam and the trap. Approximately 10 million helium atoms are trapped at temperatures of ∼ 1mK. We use phase modulation spectroscopy to measure the trapped atomic density. The cold, trapped atoms can collide to produce either atomic He+ or molecular He2+ ions by Penning Ionisation (PI) or Associative Ionisation (AI). The rate of formation of these ions is dependant upon the detuning of the trapping laser from resonance. A further laser can be used to connect the 23S1 state to another higher lying excited state, and variation of the probe laser detuning used to measure interatomic collision potential. Electron-atom collision processes are studied using a monochromatic electron beam with a well defined spatial current distribution. The total trap loss due to electron collisions is measured as a function of electron energy. Results will be presented for these atomic collision physics measurements involving cold, trapped metastable helium atoms. Copyright (1999) Australian Optical Society

  12. Analysis of the atom-number correlation function in a few-atom trap

    Choi, Youngwoon; Yoon, Seokchan; Kang, Sungsam; Kim, Woongnae; Lee, Jai-Hyung; An, Kyungwon

    2006-01-01

    Stochastic properties of loading and loss mechanism in a few atom trap are analyzed. An approximate formula is derived for the atom-number correlation function for the trapped atoms in the limit of reasonably small two-atom loss rate. Validity of the approximate formula is confirmed by numerical simulations.

  13. Production of rovibronic ground-state 85 Rb133 Cs molecules via photoassociation to Ω = 1 states

    Shimasaki, Toshihiko; Kim, Jin Tae; Demille, David

    2016-05-01

    We have extensively investigated short-range photoassociation (PA) to the (2) 3Π1 , (2) 1Π1 , and (3) 3Σ1+ states of 85 Rb133 Cs in the region between 11650 cm-1 and 12100 cm-1, where strong mixing between triplet and singlet states is expected. In contrast to the previously observed two-photon cascade decay from the (2) 3Π0 states, here we observe that the PA excited states can directly decay to the rovibronic ground state X1Σ+(v = 0 , J = 0) by a one-photon transition. We have observed rich hyperfine structures of the PA states, which were unresolved in previous cold beam experiments in the same region. Based on the analysis of vibrational and rotational branching ratios in the decay process to the X1Σ+ state, we will discuss the molecule production rate in comparison with that for PA to the (2) 3Π0 states. We will also report on a similar study of PA to the B1 Π and (2) 3Σ1+ states of 85 Rb133 Cs, which also produce the rovibronic ground state X1Σ+(v = 0 , J = 0) via direct one-photon decay.

  14. Cold atom interferometers and their applications in precision measurements

    Jin WANG; Lin ZHO; Run-bing LI; Min LIU; Ming-sheng ZHAN

    2009-01-01

    Experimental realization of cold 85Rb atom interferometers and their applications in precision meademonstrated: Detailed descriptions of the interferometers are given including manipulation of cold atoms, Rabi oscillation, stimulated Raman transitions, and optical pumping. As an example of using atom interferometers in precision measurements, the quadratic Zeeman shift of hyperfine sublevels of 85Rb was determined.

  15. Polarization criteria for magnetostatic traps for neutral atoms

    We investigated the limits of magnetostatic methods of trapping neutral atoms in a spot of small size and small polarization misalignment. General criteria on the trapping temperature as a function of size and misalignment parameters are established for various types of static magnetic field traps and for a type with rotating field invented recently by E.A. Cornell. In particular, we show that the upper temperature bound for a class of typical traps does not depend on the magnetic field magnitude. Also we found a variant of rotating field trap with new features. (author). 8 refs., 1 fig

  16. Dynamics of atom trapping in an rf-dressed potential

    Chakraborty, A; Ram, S P; Tiwari, S K; Rawat, H S

    2016-01-01

    The dynamics of atom trapping in a radio-frequency-dressed-state potential formed by static and radio frequency (rf) fields has been studied using the Direct Simulation Monte Carlo (DSMC) technique. Using the simulations, a case of formation of a toroidal trap for cold $^{87}Rb$ atoms is investigated for atoms trapped in a static quadrupole magnetic trap and exposed to an rf-field with temporally increasing amplitude and decreasing frequency. We first calculate the adiabatic rf-dressed potential for an atom interacting with these fields and then apply DSMC algorithm to simulate the motion of the atom in this time dependent adiabatic potential. In the simulations the Landau-Zener (LZ) transition probability is calculated to know if the atom is in the trappable or untrappable dressed state. The results show that, initially at lower rf-field strength, the rf-field ejects atoms from the trap and leads to evaporative cooling of the atom cloud. However at higher rf-field strength, the atoms make LZ transition to th...

  17. Trapping fermionic and bosonic helium atoms

    Stas, R.J.W.

    2005-01-01

    This thesis presents experimental and theoretical work performed at the Laser Centre of the Vrije Universiteit in Amsterdam to study laser-cooled metastable triplet helium atoms. Samples containing about 3x10^8 helium atoms-either fermionic helium-3 atoms, bosonic helium-4 atoms or mixtures thereof

  18. Optical molasses, laser traps, and ultracold atoms

    There is dramatic progress in the demonstration of the mechanical effects of light on atoms. The laser cooling and stopping of atoms in an atomic beam were followed by the 3-D cooling and confinement of atoms with laser light. The authors survey the recent major experimental advances and try to point out some interesting physics that can be done in this newly accessible domain of gaseous atoms at low temperatures and possibly high densities

  19. The determination of potential energy curve and dipole moment of the (5)0{sup +} electronic state of {sup 85}Rb{sup 133}Cs molecule by high resolution photoassociation spectroscopy

    Yuan, Jinpeng; Zhao, Yanting, E-mail: zhaoyt@sxu.edu.cn; Ji, Zhonghua; Li, Zhonghao; Xiao, Liantuan; Jia, Suotang [State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006 (China); Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006 (China); Kim, Jin-Tae, E-mail: kimjt@Chosun.ac.kr [Department of Photonic Engineering, Chosun University, Gwangju 501-759 (Korea, Republic of)

    2015-12-14

    We present the formation of ultracold {sup 85}Rb{sup 133}Cs molecules in the (5)0{sup +} electronic state by photoassociation and their detection via resonance-enhanced two-photon ionization. Up to v = 47 vibrational levels including the lowest v = 0 vibrational and lowest J = 0 levels are identified with rotationally resolved high resolution photoassociation spectra. Precise Dunham coefficients are determined for the (5)0{sup +} state with high accuracy, then the Rydberg-Klein-Rees potential energy curve is derived. The electric dipole moments with respect to the vibrational numbers of the (5)0{sup +} electronic state of {sup 85}Rb{sup 133}Cs molecule are also measured in the range between 1.9 and 4.8 D. These comprehensive studies on previously unobserved rovibrational levels of the (5)0{sup +} state are helpful to understand the molecular structure and discover suitable transition pathways for transferring ultracold atoms to deeply bound rovibrational levels of the electronic ground state.

  20. A Novel Gravito-Optical Surface Trap for Neutral Atoms

    XIE Chun-Xia; WANG Zhengling; YIN Jian-Ping

    2006-01-01

    @@ We propose a novel gravito-optical surface trap (GOST) for neutral atoms based on one-dimensional intensity gradient cooling. The surface optical trap is composed of a blue-detuned reduced semi-Gaussian laser beam (SGB), a far-blue-detuned dark hollow beam and the gravity field.

  1. Energy fluctuations induced by stochastic frequency changes in atom traps

    We study the quantum description of energy fluctuations induced by stochastic changes in the frequency of atom traps. Using the connection between classical and quantum descriptions of parametric oscillators, the classical cumulant expansion method is used to obtain quantum results beyond standard perturbation theory. Both the case of static and time-dependent traps are explicitly worked out

  2. Manipulating Neutral Atoms in Chip-Based Magnetic Traps

    Aveline, David; Thompson, Robert; Lundblad, Nathan; Maleki, Lute; Yu, Nan; Kohel, James

    2009-01-01

    Several techniques for manipulating neutral atoms (more precisely, ultracold clouds of neutral atoms) in chip-based magnetic traps and atomic waveguides have been demonstrated. Such traps and waveguides are promising components of future quantum sensors that would offer sensitivities much greater than those of conventional sensors. Potential applications include gyroscopy and basic research in physical phenomena that involve gravitational and/or electromagnetic fields. The developed techniques make it possible to control atoms with greater versatility and dexterity than were previously possible and, hence, can be expected to contribute to the value of chip-based magnetic traps and atomic waveguides. The basic principle of these techniques is to control gradient magnetic fields with suitable timing so as to alter a trap to exert position-, velocity-, and/or time-dependent forces on atoms in the trap to obtain desired effects. The trap magnetic fields are generated by controlled electric currents flowing in both macroscopic off-chip electromagnet coils and microscopic wires on the surface of the chip. The methods are best explained in terms of examples. Rather than simply allowing atoms to expand freely into an atomic waveguide, one can give them a controllable push by switching on an externally generated or a chip-based gradient magnetic field. This push can increase the speed of the atoms, typically from about 5 to about 20 cm/s. Applying a non-linear magnetic-field gradient exerts different forces on atoms in different positions a phenomenon that one can exploit by introducing a delay between releasing atoms into the waveguide and turning on the magnetic field.

  3. Eliminating light shifts in single-atom optical traps

    Hutzler, Nicholas R; Yu, Yichao; Ni, Kang-Kuen

    2016-01-01

    Microscopically controlled neutral atoms in optical tweezers and lattices have led to exciting advances in the study of quantum information and quantum many-body systems. The light shifts of atomic levels from the trapping potential in these systems can result in detrimental effects such as fluctuating dipole force heating, inhomogeneous detunings, and inhibition of laser cooling, which limits the atomic species that can be manipulated. In particular, these light shifts can be large enough to prevent loading into optical tweezers directly from a magneto-optical trap. We present a general solution to these limitations by loading, cooling, and imaging single atoms with temporally alternating beams. Because this technique does not depend on any specific spectral properties, we expect it to enable the optical tweezer method to control nearly any atomic or molecular species that can be laser cooled and optically trapped. Furthermore, we present an analysis of the role of heating and required cooling for single ato...

  4. In-trap fluorescence detection of atoms in a microscopic dipole trap

    Hilliard, A J; Sompet, P; Carpentier, A V; Andersen, M F

    2015-01-01

    We investigate fluorescence detection using a standing wave of blue-detuned light of one or more atoms held in a deep, microscopic dipole trap. The blue-detuned standing wave realizes a Sisyphus laser cooling mechanism so that an atom can scatter many photons while remaining trapped. When imaging more than one atom, the blue detuning limits loss due to inelastic light-assisted collisions. Using this standing wave probe beam, we demonstrate that we can count from one to the order of 100 atoms in the microtrap with sub-poissonian precision.

  5. Deep optical trap for cold alkaline-Earth atoms.

    Cruz, Luciano S; Sereno, Milena; Cruz, Flavio C

    2008-03-01

    We describe a setup for a deep optical dipole trap or lattice designed for holding atoms at temperatures of a few mK, such as alkaline-Earth atoms which have undergone only regular Doppler cooling. We use an external optical cavity to amplify 3.2 W from a commercial single-frequency laser at 532 nm to 523 W. Powers of a few kW, attainable with low-loss optics or higher input powers, allow larger trap volumes for improved atom transfer from magneto-optical traps. We analyze possibilities for cooling inside the deep trap, the induced Stark shifts for calcium, and a cancellation scheme for the intercombination clock transition using an auxiliary laser. PMID:18542375

  6. Analysis of a single-atom dipole trap

    We describe a simple experimental technique which allows us to store a single 87Rb atom in an optical dipole trap. Due to light-induced two-body collisions during the loading stage of the trap the maximum number of captured atoms is locked to one. This collisional blockade effect is confirmed by the observation of photon antibunching in the detected fluorescence light. The spectral properties of single photons emitted by the atom were studied with a narrow-band scanning cavity. We find that the atomic fluorescence spectrum is dominated by the spectral width of the exciting laser light field. In addition we observe a spectral broadening of the atomic fluorescence light due to the Doppler effect. This allows us to determine the mean kinetic energy of the trapped atom corresponding to a temperature of 105 μK. This simple single-atom trap is the key element for the generation of atom-photon entanglement required for future applications in quantum communication and a first loophole-free test of Bell's inequality

  7. Trapping fermionic and bosonic helium atoms

    Stas, R. J. W.

    2005-01-01

    This thesis presents experimental and theoretical work performed at the Laser Centre of the Vrije Universiteit in Amsterdam to study laser-cooled metastable triplet helium atoms. Samples containing about 3x10^8 helium atoms-either fermionic helium-3 atoms, bosonic helium-4 atoms or mixtures thereof-are cooled to a temperature around 1 mK and form the starting point of the presented studies. The studies include an investigation of cold ionizing collisions in the absence of resonant light, an i...

  8. Atom-molecule collisions in an optically trapped gas

    Zahzam, Nassim; Vogt, Thibault; Mudrich, Marcel; Comparat, Daniel; Pillet, Pierre

    2005-01-01

    Cold inelastic collisions between confined cesium (Cs) atoms and Cs$\\_2$ molecules are investigated inside a CO$\\_2$ laser dipole trap. Inelastic atom-molecule collisions can be observed and measured with a rate coefficient of $\\sim 2.5 \\times 10^{-11} $cm$^3$ s$^{-1}$, mainly independent of the molecular ro-vibrational state populated. Lifetimes of purely atomic and molecular samples are essentially limited by rest gas collisions. The pure molecular trap lifetime ranges 0,3-1 s, four times s...

  9. Next Generation JPL Ultra-Stable Trapped Ion Atomic Clocks

    Burt, Eric; Tucker, Blake; Larsen, Kameron; Hamell, Robert; Tjoelker, Robert

    2013-01-01

    Over the past decade, trapped ion atomic clock development at the Jet Propulsion Laboratory (JPL) has focused on two directions: 1) new atomic clock technology for space flight applications that require strict adherence to size, weight, and power requirements, and 2) ultra-stable atomic clocks, usually for terrestrial applications emphasizing ultimate performance. In this paper we present a new ultra-stable trapped ion clock designed, built, and tested in the second category. The first new standard, L10, will be delivered to the Naval Research Laboratory for use in characterizing DoD space clocks.

  10. PYRAMIDAL-HOLLOW-BEAM DIPOLE TRAP FOR ALKALI ATOMS

    YIN JIAN-PING; GAO WEI-JIAN; WANG YU-ZHU; ZHU YI-FU; WANG YI-QIU

    2000-01-01

    We propose a dark gravito-optical dipole trap, for alkali atoms, consisting of a blue-detuned, pyramidal-hollow laser beam propagating upward and the gravity field. When cold atoms from a magneto-optical trap are loaded into the pyramidal-hollow beam and bounce inside the pyramidal-hollow beam, they experience efficient Sisyphus cooling and geometric cooling induced by the pyramidal-hollow beam and the weak repumping beam propagating downward. Our study shows that an ultracold and dense atomic sample with an equilibrium 3D momentum of ~ 3hk and an atomic density above the point of Bose-Einstein condensation may be obtained in this pure optical trap.

  11. Oscillation Frequencies for Simultaneous Trapping of Heteronuclear Alkali Atoms

    Kaur, Kiranpreet; Arora, Bindiya

    2016-01-01

    We investigate oscillation frequencies for simultaneous trapping of more than one type of alkali atoms in a common optical lattice. For this purpose, we present numerical results for magic trapping conditions, where the oscillation frequencies for two different kind of alkali atoms using laser lights in the wavelength range 500-1200 nm are same. These wavelengths will be of immense interest for studying static and dynamic properties of boson-boson, boson-fermion, fermion-fermion, and boson-boson-boson mixtures involving different isotopes of Li, Na, K, Rb, Cs and Fr alkali atoms. In addition to this, we were also able to locate a magic wavelength around 808.1 nm where all the three Li, K, and Rb atoms are found to be suitable for oscillating at the same frequency in a common optical trap.

  12. A quasi-electrostatic trap for neutral atoms

    This thesis reports on the realization of a ''quasi-electrostatic trap'' (QUEST) for neutral atoms. Cesium (133Cs) and Lithium (7Li) atoms are stored, which represents for the first time a mixture of different species in an optical dipole trap. The trap is formed by the focused Gaussian beam of a 30 W cw CO2-laser. For a beam waist of 108 μm the resulting trap depth is κB x 118 μK for Cesium and κB x 48 μK for Lithium. We transfer up to 2 x 106 Cesium and 105 Lithium atoms from a magneto-optical trap into the QUEST. When simultaneously transferred, the atom number currently is reduced by roughly a factor of 10. Since photon scattering from the trapping light can be neglected, the QUEST represents an almost perfect conservative trapping potential. Atoms in the QUEST populate the electronic ground state sublevels. Arbitrary sublevels can be addressed via optical pumping. Due to the very low background gas pressure of 2 x 10-11 mbar storage times of several minutes are realized. Evaporative cooling of Cesium is observed. In addition, laser cooling is applied to the trapped Cesium sample, which reduces the temperature from 25 μK to a value below 7 μK. If prepared in the upper hyper-fine ground state sublevel, spin changing collisions are observed not only within one single species, but also between the two different species. The corresponding relaxation rates are quantitatively analyzed. (orig.)

  13. Collisional properties of trapped cold chromium atoms

    Pavlovich, Z; Côté, R; Sadeghpour, H R; Pavlovic, Zoran; Roos, Bjoern O.; Côté, Robin

    2004-01-01

    We report on calculations of the elastic cross section and thermalization rate for collision between two maximally spin-polarized chromium atoms in the cold and ultracold regimes, relevant to buffer-gas and magneto-optical cooling of chromium atoms. We calculate ab initio potential energy curves for Cr2 and the van der Waals coefficient C6, and construct interaction potentials between two colliding Cr atoms. We explore the effect of shape resonances on elastic cross section, and find that they dramatically affect the thermalization rate. Our calculated value for the s-wave scattering length is compared in magnitude with a recent measurement at ultracold temperatures.

  14. Cold Atom Source Containing Multiple Magneto-Optical Traps

    Ramirez-Serrano, Jaime; Kohel, James; Kellogg, James; Lim, Lawrence; Yu, Nan; Maleki, Lute

    2007-01-01

    An apparatus that serves as a source of a cold beam of atoms contains multiple two-dimensional (2D) magneto-optical traps (MOTs). (Cold beams of atoms are used in atomic clocks and in diverse scientific experiments and applications.) The multiple-2D-MOT design of this cold atom source stands in contrast to single-2D-MOT designs of prior cold atom sources of the same type. The advantages afforded by the present design are that this apparatus is smaller than prior designs.

  15. Laser cooling, trapping, and Rydberg spectroscopy of neutral holmium atoms

    Hostetter, James Allen

    This thesis focuses on progress towards using ensembles of neutral holmium for use in quantum computing operations. We are particularly interested in using a switchable interaction between neutral atoms, the Rydberg blockade, to implement a universal set of quantum gates in a collective encoding scheme that presents many benefits over quantum computing schemes which rely on physically distinct qubits. We show that holmium is uniquely suited for operations in a collective encoding basis because it has 128 ground hyperfine states, the largest number of any stable, neutral atom. Holmium is a rare earth atom that is very poorly described for our purposes as it has never been cooled and trapped, its spectrum is largely unknown, and it presents several unique experimental challenges related to its complicated atomic structure and short wavelength transitions. We demonstrate important progress towards overcoming these challenges. We produce the first laser cooling and trapping of holmium into a MOT. Because we use a broad cooling transition, our cooling technique does not require the use of a Zeeman slower. Using MOT depletion spectroscopy, we provide precise measurements of holmium's Rydberg states and its ionization potential. Our work continues towards cooling holmium into a dipole trap by calculating holmium's AC polarizability and demonstrating the results of early attempts at an optical dipole trap. We provide details of future upgrades to the experimental apparatus and discuss interesting potential for using holmium in quantum computing using single atoms in a magnetically trapped lattice. This thesis shows several promising indicators for continued work in this field.

  16. Construction of a single atom trap for quantum information protocols

    Shea, Margaret E.; Baker, Paul M.; Gauthier, Daniel J.; Duke Physics Department Team

    2016-05-01

    The field of quantum information science addresses outstanding problems such as achieving fundamentally secure communication and solving computationally hard problems. Great progress has been made in the field, particularly using photons coupled to ions and super conducting qubits. Neutral atoms are also interesting for these applications and though the technology for control of neutrals lags behind that of trapped ions, they offer some key advantages: primarily coupling to optical frequencies closer to the telecom band than trapped ions or superconducting qubits. Here we report progress on constructing a single atom trap for 87 Rb. This system is a promising platform for studying the technical problems facing neutral atom quantum computing. For example, most protocols destroy the trap when reading out the neutral atom's state; we will investigate an alternative non-destructive state detection scheme. We detail the experimental systems involved and the challenges addressed in trapping a single atom. All of our hardware components are off the shelf and relatively inexpensive. Unlike many other systems, we place a high numerical aperture lens inside our vacuum system to increase photon collection efficiency. We gratefully acknowledge the financial support of the ARO through Grant # W911NF1520047.

  17. Trapping cold molecules and atoms: Simultaneous magnetic deceleration and trapping of cold molecular Oxygen with Lithium atoms

    Akerman, Nitzan; Karpov, Michael; Segev, Yair; Bibelink, Natan; Narevicius, Julia; Narevicius, Edvardas

    2016-05-01

    Cooling molecules to the ultra-cold regime remains a major challenge in the growing field of cold molecules. The molecular internal degrees of freedom complicate the effort of direct application of laser cooling. An alternative and general path towards ultra-cold molecules relies on sympathetic cooling via collisions with laser-cooled atoms. Here, we demonstrate the first step towards application of sympathetic cooling by co-trapping of molecular Oxygen with Lithium atoms in a magnetic trap at a temperature of 300 mK. Our experiment begins with a pulsed supersonic beam which is a general source for cold high-flux atomic and molecular beams. Although the supersonic expansion efficiently cools the beam to temperatures below 1K, it also accelerates the beam to high mean velocities. We decelerate a beam of O2 in a moving magnetic trap decelerator from 375 m/s to a stop. We entrained the molecular beam with Li atoms by laser ablation prior to deceleration. The deceleration ends with loading the molecules and atoms into a static quadrupole trap, which is generated by two permanent magnets. We estimate 109 trapped molecules with background limited lifetime of 0.6 Sec. Our achievement enables application of laser cooling on the Li atoms in order to sympathetically cool the O2.

  18. Proposed magneto-electrostatic ring trap for neutral atoms

    Hopkins, A; Mabuchi, H; Hopkins, Asa; Lev, Benjamin; Mabuchi, Hideo

    2004-01-01

    We propose a novel trap for confining cold neutral atoms in a ring using a magneto-electrostatic potential. The trapping potential is derived from a combination of a repulsive magnetic field from a hard drive atom mirror and the attractive potential produced by a charged disk patterned on the hard drive surface. We calculate a trap frequency of [29.8, 42.8, 63.1] kHz and a depth of [16.3, 21.6, 21.6] MHz for [133Cs, 87Rb, 40K], and discuss a simple loading scheme and a method for fabrication. This device provides a one-dimensional potential in a ring geometry that may be of interest to the study of trapped quantum degenerate one-dimensional gases.

  19. Design of a dual species atom interferometer for space

    Schuldt, Thilo; Krutzik, Markus; Bote, Lluis Gesa; Gaaloul, Naceur; Hartwig, Jonas; Ahlers, Holger; Herr, Waldemar; Posso-Trujillo, Katerine; Rudolph, Jan; Seidel, Stephan; Wendrich, Thijs; Ertmer, Wolfgang; Herrmann, Sven; Kubelka-Lange, André; Milke, Alexander; Rievers, Benny; Rocco, Emanuele; Hinton, Andrew; Bongs, Kai; Oswald, Markus; Franz, Matthias; Hauth, Matthias; Peters, Achim; Bawamia, Ahmad; Wicht, Andreas; Battelier, Baptiste; Bertoldi, Andrea; Bouyer, Philippe; Landragin, Arnaud; Massonnet, Didier; Lévèque, Thomas; Wenzlawski, Andre; Hellmig, Ortwin; Windpassinger, Patrick; Sengstock, Klaus; von Klitzing, Wolf; Chaloner, Chris; Summers, David; Ireland, Philip; Mateos, Ignacio; Sopuerta, Carlos F; Sorrentino, Fiodor; Tino, Guglielmo M; Williams, Michael; Trenkel, Christian; Gerardi, Domenico; Chwalla, Michael; Burkhardt, Johannes; Johann, Ulrich; Heske, Astrid; Wille, Eric; Gehler, Martin; Cacciapuoti, Luigi; Gürlebeck, Norman; Braxmaier, Claus; Rasel, Ernst

    2014-01-01

    Atom interferometers have a multitude of proposed applications in space including precise measurements of the Earth's gravitational field, in navigation & ranging, and in fundamental physics such as tests of the weak equivalence principle (WEP) and gravitational wave detection. While atom interferometers are realized routinely in ground-based laboratories, current efforts aim at the development of a space compatible design optimized with respect to dimensions, weight, power consumption, mechanical robustness and radiation hardness. In this paper, we present a design of a high-sensitivity differential dual species $^{85}$Rb/$^{87}$Rb atom interferometer for space, including physics package, laser system, electronics and software. The physics package comprises the atom source consisting of dispensers and a 2D magneto-optical trap (MOT), the science chamber with a 3D-MOT, a magnetic trap based on an atom chip and an optical dipole trap (ODT) used for Bose-Einstein condensate (BEC) creation and interferometry...

  20. Experimental study of vapor-cell magneto-optical traps for efficient trapping of radioactive atoms

    We have studied magneto-optical traps (MOTs) for efficient on-line trapping of radioactive atoms. After discussing a model of the trapping process in a vapor cell and its efficiency, we present the results of detailed experimental studies on Rb MOTs. Three spherical cells of different sizes were used. These cells can be easily replaced, while keeping the rest of the apparatus unchanged: atomic sources, vacuum conditions, magnetic field gradients, sizes and power of the laser beams, detection system. By direct comparison, we find that the trapping efficiency only weakly depends on the MOT cell size. It is also found that the trapping efficiency of the MOT with the smallest cell, whose diameter is equal to the diameter of the trapping beams, is about 40% smaller than the efficiency of larger cells. Furthermore, we also demonstrate the importance of two factors: a long coated tube at the entrance of the MOT cell, used instead of a diaphragm; and the passivation with an alkali vapor of the coating on the cell walls, in order to minimize the losses of trappable atoms. These results guided us in the construction of an efficient large-diameter cell, which has been successfully employed for on-line trapping of Fr isotopes at INFN's national laboratories in Legnaro, Italy. (authors)

  1. Nonperturbative and perturbative treatments of parametric heating in atom traps

    Jauregui, R

    2001-01-01

    We study the quantum description of parametric heating in harmonic potentials both nonperturbatively and perturbatively, having in mind atom traps. The first approach establishes an explicit connection between classical and quantum descriptions; it also gives analytic expressions for properties such as the width of fractional frequency parametric resonances. The second approach gives an alternative insight into the problem and can be directly extended to take into account nonlinear effects. This is specially important for shallow traps.

  2. Atomic physics experiments with trapped and cooled highly charged ions

    Kluge, H.-J.; Quint, W; Winters, D. F. A

    2007-01-01

    Trapping and cooling techniques have become very important for many fundamental experiments in atomic physics. When applied to highly charged ions confined in Penning traps, these procedures are very effective for testing quantum electrodynamics in extreme electromagnetic fields produced by heavy highly charged ions such as uranium U$^{91+}$. In addition, fundamental constants or nuclear ground state properties can be determined with high accuracy in these simple systems. Finally, by studying...

  3. Isotopic abundance in atom trap trace analysis

    Lu, Zheng-Tian; Hu, Shiu-Ming; Jiang, Wei; Mueller, Peter

    2014-03-18

    A method and system for detecting ratios and amounts of isotopes of noble gases. The method and system is constructed to be able to measure noble gas isotopes in water and ice, which helps reveal the geological age of the samples and understand their movements. The method and system uses a combination of a cooled discharge source, a beam collimator, a beam slower and magneto-optic trap with a laser to apply resonance frequency energy to the noble gas to be quenched and detected.

  4. Theory of output coupling for trapped fermionic atoms

    We develop a dynamic theory of output coupling for fermionic atoms initially confined in a magnetic trap. We consider an exactly soluble one-dimensional model, with a spatially localized δ-type coupling between the atoms in the trap and a continuum of free-particle external modes. The transient dynamics of the atoms, as they leave the trap, is investigated in detail. Two important special cases are considered for the confinement potential: the infinite box and the harmonic oscillator. We establish that in both cases a bound state of the coupled system appears for any value of the coupling constant, implying that the trap population does not vanish in the infinite-time limit. For weak coupling, the infinite-time spectral distribution of the outgoing atoms exhibits peaks corresponding to the initially occupied energy levels in the trap; the heights of these peaks increase with the energy. As the coupling gets stronger, the infinite-time spectral distribution is displaced towards dressed energies of the fermions in the trap. The corresponding dressed states result from the coupling between the unperturbed fermionic states in the trap, mediated by the coupling between these states and the continuum. In the strong-coupling limit, there is a reinforcement of the lowest-energy dressed mode, which contributes to the spectral distribution of the outgoing beam more strongly than the other modes. This effect is especially pronounced for the one-dimensional box, which indicates that the efficiency of the mode-reinforcement mechanism depends on the steepness of the confinement potential. In this case, a quasimonochromatic antibunched atomic beam is obtained. Results for a bosonic sample are also shown for comparison

  5. Dark Optical Lattice of Ring Traps for Cold Atoms

    Courtade, E; Houde, O; Verkerk, P; Courtade, Emmanuel; Hennequin, Daniel; Houde, Olivier; Verkerk, Philippe

    2006-01-01

    We propose a new geometry of optical lattice for cold atoms, namely a lattice made of a 1D stack of dark ring traps. It is obtained through the interference pattern of a standard Gaussian beam with a counter-propagating hollow beam obtained using a setup with two conical lenses. The traps of the resulting lattice are characterized by a high confinement and a filling rate much larger than unity, even if loaded with cold atoms from a MOT. We have implemented this system experimentally, and obtained a lattice of ring traps populated with typically 40 atoms per site with a life time of 30 ms. Applications in statistical physics, quantum computing and Bose-Einstein condensate dynamics are conceivable.

  6. Resonant quantum transitions in trapped antihydrogen atoms

    Amole, C; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Butler, E; Capra, A; Cesar, C L; Charlton, M; Deller, A; Donnan, P H; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Isaac, C A; Jonsell, S; Kurchaninov, L; Little, A; Madsen, N; McKenna, J T K; Menary, S; Napoli, S C; Nolan, P; Olchanski, K; Olin, A; Pusa, P; Rasmussen, C Ø; Robicheaux, F; Sarid, E; Shields, C R; Silveira, D M; Stracka, S; So, C; Thompson, R I; van der Werf, D P; Wurtele, J S

    2012-01-01

    The hydrogen atom is one of the most important and influential model systems in modern physics. Attempts to understand its spectrum are inextricably linked to the early history and development of quantum mechanics. The hydrogen atom’s stature lies in its simplicity and in the accuracy with which its spectrum can be measured1 and compared to theory. Today its spectrum remains a valuable tool for determining the values of fundamental constants and for challenging the limits of modern physics, including the validity of quantum electrodynamics and—by comparison with measurements on its antimatter counterpart, antihydrogen—the validity of CPT (charge conjugation, parity and time reversal) symmetry. Here we report spectroscopy of a pure antimatter atom, demonstrating resonant quantum transitions in antihydrogen. We have manipulated the internal spin state2, 3 of antihydrogen atoms so as to induce magnetic resonance transitions between hyperfine levels of the positronic ground state. We used resonant microwave...

  7. Bichromatic State-insensitive Trapping of Caesium Atoms

    Metbulut, M M

    2015-01-01

    State-insensitive dipole trapping of multilevel atoms can be achieved by an appropriate choice of the wavelength of the trapping laser, so that the interaction with the different transitions results in equal AC Stark shifts for the ground and excited states of interest. However this approach is severely limited by the availability of coherent sources at the required wavelength and of appropriate power. This work investigates state-insensitive trapping of caesium atoms for which the required wavelength of 935.6 nm is inconvenient in terms of experimental realization. Bichromatic state-insensitive trapping is proposed to overcome the lack of suitable laser sources. We first consider pairs of laser wavelengths in the ratio 1:2 and 1:3, as obtained via second- and third- harmonic generation. We found that the wavelength combinations 931.8-1863.6 nm and 927.5-2782.5 nm are suitable for state-insensitive trapping of caesium atoms. In addition, we examine bichromatic state-insensitive trapping produced by pairs of l...

  8. Bichromatic state-insensitive trapping of caesium atoms

    Metbulut, M. M.; Renzoni, F.

    2015-12-01

    State-insensitive dipole trapping of multilevel atoms can be achieved by an appropriate choice of the wavelength of the trapping laser, so that the interaction with the different transitions results in equal AC Stark shifts for the ground and excited states of interest. However this approach is severely limited by the availability of coherent sources at the required wavelength and of appropriate power. This work investigates state-insensitive trapping of caesium atoms for which the required wavelength of 935.6 nm is inconvenient in terms of experimental realization. Bichromatic state-insensitive trapping is proposed to overcome the lack of suitable laser sources. We first consider pairs of laser wavelengths in the ratio 1:2 and 1:3, as obtained via second- and third- harmonic generation. We found that the wavelength combinations 931.8-1863.6 nm and 927.5-2782.5 nm are suitable for state-insensitive trapping of caesium atoms. In addition, we examine bichromatic state-insensitive trapping produced by pairs of laser wavelengths corresponding to currently available high power lasers. These wavelength pairs were found to be in the range of 585-588 nm and 623-629 for one laser and 1064-1080 nm for the other.

  9. Resonator-Enhanced Optical Dipole Trap for Fermionic Lithium Atoms

    Mosk, A P; Moritz, H; Elsaesser, T; Weidemüller, M; Grimm, R; Elsaesser, Th.

    2001-01-01

    We demonstrate a novel optical dipole trap which is based on the enhancement of the optical power density of a Nd:YAG laser beam in a resonator. The trap is particularly suited for experiments with ultracold gases, as it combines a potential depth of order 1 mK with storage times of several tens of seconds. We study the interactions in a gas of fermionic lithium atoms in our trap and observe the influence of spin-changing collisions and off-resonant photon scattering. A key element in reaching long storage times is an ultra-low noise laser. The dependence of the storage time on laser noise is investigated.

  10. Resonator-Enhanced Optical Dipole Trap for Fermionic Lithium Atoms

    Mosk, A.; Jochim, S.; Moritz, H.; Elsaesser, Th.; Weidemueller, M.; Grimm, R

    2001-01-01

    We demonstrate a novel optical dipole trap which is based on the enhancement of the optical power density of a Nd:YAG laser beam in a resonator. The trap is particularly suited for experiments with ultracold gases, as it combines a potential depth of order 1 mK with storage times of several tens of seconds. We study the interactions in a gas of fermionic lithium atoms in our trap and observe the influence of spin-changing collisions and off-resonant photon scattering. A key element in reachin...

  11. Theoretical evaluation of matrix effects on trapped atomic levels

    We suggest a theoretical model for calculating the matrix perturbation on the spectra of atoms trapped in rare gas systems. The model requires the ''potential curves'' of the diatomic system consisting of the trapped atom interacting with one from the matrix and relies on the approximation that the total matrix perturbation is a scalar sum of the pairwise interactions with each of the lattice sites. Calculations are presented for the prototype systems Na in Ar. Attempts are made to obtain ab initio estimates of the Jahn-Teller effects for excited states. Comparison is made with our recent Matrix-Isolation Spectroscopic (MIS) data. 10 refs., 3 tabs

  12. Atom trap trace analysis of {sup 39}Ar

    Welte, Joachim

    2011-12-14

    Detection of {sup 39}Ar in natural water samples can be employed for radiometric dating on a timescale of 50 to 1000 years before present. This experimental work comprises the setup of an atomic beam and trap apparatus that captures and detects {sup 39}Ar atoms by the laser-cooling technique ''Atom Trap Trace Analysis''. With this approach, the limitations of low-level counting, regarding sample size and measurement time, could be overcome. In the course of this work, the hyperfine structure spectrum of the cooling transition 1s{sub 5}-2p{sub 9} has been experimentally determined. A high intensity, optically collimated beam of slow metastable argon atoms has been set up and fluorescence detection of individual {sup 39}Ar atoms in a magneto-optical trap is realized. {sup 39}Ar count rates of 1 atom in about 4 hours have been achieved for atmospheric argon. Recent improvements further suggest that even higher count rates of 1 atom/hour are within reach.

  13. Cold atoms in microscopic traps from wires to chips

    Cassettari, D

    2000-01-01

    Ioffe-Pritchard trap. In the latter we have achieved the trapping parameters required in the experiments with Bose-Einstein condensates with much reduced power consumption. In a second time we have replaced the free standing wires with an atom chip, which we have used to compress the atomic cloud in potentials with trap frequencies above 100 kHz and ground state sizes below 100 nm. Such potentials are especially interesting for quantum information proposals of performing quantum gate operations with controlled collisions between trapped atoms. Finally, by combining two wire guides we have experimentally realized an innovative kind of beam splitter for guided atoms. We have investigated the splitting potential generated by a Y-shaped wire which has one input, i.e. the central arm of the Y, and two outputs corresponding to the left and right arms of the Y. By tuning the current ratio in the two outputs we have observed atoms switching from left to right as well as symmetric splitting. This and other similar des...

  14. Vapor generation and atom traps: Atomic absorption spectrometry at the ng/L level

    Atom-trapping atomic absorption spectrometry is a technique that allows detection at the ng/L level for several analytes such as As, Se, Sb, Pb, Bi, Cd, In, Tl, Te, Sn and Hg. The principle involves generation of volatile species, usually hydrides, trapping these species on the surface of an atom trap held at an optimized temperature and, finally, revolatilizing the analyte species by rapid heating of the trap and transporting them in a carrier gas to a heated quartz tube, as commonly used with hydride generation AAS systems. A transient signal having, in most cases, a full width at half maximum of less than 1 s is obtained. The atom trap may be a quartz surface or a W-coil; the former is heated externally and the latter is heated resistively. Both collection and revolatilization temperatures are optimized. In some cases, the W-coil itself is used as an electrothermal atomizer and a heated quartz tube is then not needed. The evolution of these traps starts with the well-known Watling's slotted quartz tube (SQT), continues with atom trapping SQT and finally reaches the present traps mentioned above. The analytical figures of merit for these traps need to be standardized. Naturally, enhancement is on characteristic concentration, C0, where the change in characteristic mass, m0, can be related to trapping efficiency. Novel terms are suggested for E, enhancement factor; such as Emax, maximum enhancement factor; Et, enhancement for 1.0 minute sampling and Ev, enhancement for 1.0 mL of sample. These figures will allow easy comparison of results from different laboratories as well as different analytes and/or traps

  15. Vapor generation and atom traps: Atomic absorption spectrometry at the ng/L level

    Ataman, O. Yavuz [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey)], E-mail: ataman@metu.edu.tr

    2008-08-15

    Atom-trapping atomic absorption spectrometry is a technique that allows detection at the ng/L level for several analytes such as As, Se, Sb, Pb, Bi, Cd, In, Tl, Te, Sn and Hg. The principle involves generation of volatile species, usually hydrides, trapping these species on the surface of an atom trap held at an optimized temperature and, finally, revolatilizing the analyte species by rapid heating of the trap and transporting them in a carrier gas to a heated quartz tube, as commonly used with hydride generation AAS systems. A transient signal having, in most cases, a full width at half maximum of less than 1 s is obtained. The atom trap may be a quartz surface or a W-coil; the former is heated externally and the latter is heated resistively. Both collection and revolatilization temperatures are optimized. In some cases, the W-coil itself is used as an electrothermal atomizer and a heated quartz tube is then not needed. The evolution of these traps starts with the well-known Watling's slotted quartz tube (SQT), continues with atom trapping SQT and finally reaches the present traps mentioned above. The analytical figures of merit for these traps need to be standardized. Naturally, enhancement is on characteristic concentration, C{sub 0}, where the change in characteristic mass, m{sub 0}, can be related to trapping efficiency. Novel terms are suggested for E, enhancement factor; such as E{sub max}, maximum enhancement factor; E{sub t}, enhancement for 1.0 minute sampling and E{sub v}, enhancement for 1.0 mL of sample. These figures will allow easy comparison of results from different laboratories as well as different analytes and/or traps.

  16. Vapor generation and atom traps: Atomic absorption spectrometry at the ng/L level

    Ataman, O. Yavuz

    2008-08-01

    Atom-trapping atomic absorption spectrometry is a technique that allows detection at the ng/L level for several analytes such as As, Se, Sb, Pb, Bi, Cd, In, Tl, Te, Sn and Hg. The principle involves generation of volatile species, usually hydrides, trapping these species on the surface of an atom trap held at an optimized temperature and, finally, revolatilizing the analyte species by rapid heating of the trap and transporting them in a carrier gas to a heated quartz tube, as commonly used with hydride generation AAS systems. A transient signal having, in most cases, a full width at half maximum of less than 1 s is obtained. The atom trap may be a quartz surface or a W-coil; the former is heated externally and the latter is heated resistively. Both collection and revolatilization temperatures are optimized. In some cases, the W-coil itself is used as an electrothermal atomizer and a heated quartz tube is then not needed. The evolution of these traps starts with the well-known Watling's slotted quartz tube (SQT), continues with atom trapping SQT and finally reaches the present traps mentioned above. The analytical figures of merit for these traps need to be standardized. Naturally, enhancement is on characteristic concentration, C0, where the change in characteristic mass, m0, can be related to trapping efficiency. Novel terms are suggested for E, enhancement factor; such as Emax, maximum enhancement factor; Et, enhancement for 1.0 minute sampling and Ev, enhancement for 1.0 mL of sample. These figures will allow easy comparison of results from different laboratories as well as different analytes and/or traps.

  17. Atom trapping: application to electron collision studies of metastable helium

    Full text: We report on the first measurements of electron scattering from metastable helium atoms (He) confined in a magneto-optic trap (MOT). Using conventional crossed beam techniques, measurement of electron scattering cross sections for He is experimentally very difficult, due the intrinsically low atomic densities produced by nozzle discharge sources, and the need to locate the interaction region well away from stray electric and magnetic fields. Electron interactions with excited state atoms are fundamentally important to many naturally processes in atmospheric and astrophysical chemistry, gas lasers and plasma processing. Until these experiments, no data for He existed in the intermediate (10-100 eV) range to verify theoretical predictions. Our MOT contains up to 108 atoms at temperatures of ∼1mK that act as a high (∼109 cm-3) density target for a pulsed electron beam. We employ optical molasses to reduce the atomic velocity, and hence the trap decay time when released from the optical and magnetic fields. The total cross section is determined using phase modulation spectroscopy to measure the fractional loss rate of the trapped atoms with the electron gun on, and the electron current density is measured using scanning wire techniques to yield the absolute total cross section

  18. Quantum computing with trapped ions, atoms and light

    We consider experimental issues relevant to quantum computing, and discuss the best way to achieve the essential requirements of reliable quantum memory and gate operations. Nuclear spins in trapped ions or atoms are a very promising candidate for the qubits. We estimate the parameters required to couple atoms using light via cavity QED in order to achieve quantum gates. We briefly comment on recent improvements to the Cirac-Zoller method for coupling trapped ions via their vibrational degree of freedom. Error processes result in a trade-off between quantum gate speed and failure probability. A useful quantum computer does appear to be feasible using a combination of ion trap and optical methods. The best understood method to stabilize a large computer relies on quantum error correction. The essential ideas of this are discussed, and recent estimates of the noise requirements in a quantum computing device are given

  19. An architecture for quantum computation with magnetically trapped Holmium atoms

    Saffman, Mark; Hostetter, James; Booth, Donald; Collett, Jeffrey

    2016-05-01

    Outstanding challenges for scalable neutral atom quantum computation include correction of atom loss due to collisions with untrapped background gas, reduction of crosstalk during state preparation and measurement due to scattering of near resonant light, and the need to improve quantum gate fidelity. We present a scalable architecture based on loading single Holmium atoms into an array of Ioffe-Pritchard traps. The traps are formed by grids of superconducting wires giving a trap array with 40 μm period, suitable for entanglement via long range Rydberg gates. The states | F = 5 , M = 5 > and | F = 7 , M = 7 > provide a magic trapping condition at a low field of 3.5 G for long coherence time qubit encoding. The F = 11 level will be used for state preparation and measurement. The availability of different states for encoding, gate operations, and measurement, spectroscopically isolates the different operations and will prevent crosstalk to neighboring qubits. Operation in a cryogenic environment with ultra low pressure will increase atom lifetime and Rydberg gate fidelity by reduction of blackbody induced Rydberg decay. We will present a complete description of the architecture including estimates of achievable performance metrics. Work supported by NSF award PHY-1404357.

  20. Harmonic trap resonance enhanced synthetic atomic spin-orbit coupling

    Wu, Ling-Na; Luo, Xinyu; Xu, Zhi-Fang; Ueda, Masahito; Wang, Ruquan; You, Li

    2016-05-01

    The widely adopted scheme for synthetic atomic spin-orbit coupling (SOC) is based on the momentum sensitive Raman coupling, which is easily implemented in one spatial dimension. Recently, schemes based on pulsed or periodically modulating gradient magnetic field (GMF) were proposed and the main characteristic features have subsequently been demonstrated. The present work reports an experimental discovery and the associated theoretical understanding of tuning the SOC strength synthesized with GMF through the motional resonance of atomic center-of-mass in a harmonic trap. In some limits, we observe up to 10 times stronger SOC compared to the momentum impulse from GMF for atoms in free space.

  1. Large amplitude spin oscillations in a collisionless trapped atomic gas

    Piechon, F; Laloë, F

    2009-01-01

    We propose an explanation of the recently observed strong spin segregation in a trapped Fermi gas by Du et al. Numerical and analytical solutions of a spin 1/2 kinetic equation in a collisionless regime explain quantitatively the observation of an "anomalous" large time scale and amplitude of the segregation. The key difference with previous experiment on bosons rests more in the diluteness of the gas than in the quantum statistics of the atoms. When they undergo fast ballistic oscillations in the trap, they average the inhomogeneous external field in an energy dependent way, so that their transverse spin precession frequency becomes proportional to their energy. Interactions between atoms of different energies and different spin directions then involve the identical spin rotation effect (ISRE), which transfers atoms to the up or down spin state in an energy dependent way. Since low energy atoms are closer to the center of the trap than high energy atoms, which can visit its edges, the final outcome is a stro...

  2. Coherence properties of nanofiber-trapped cesium atoms

    Reitz, D; Mitsch, R; Schneeweiss, P; Rauschenbeutel, A

    2013-01-01

    We experimentally study the ground state coherence properties of cesium atoms in a nanofiber-based two-color dipole trap, localized 200 nm away from the fiber surface. Using microwave radiation to coherently drive the clock transition, we record Ramsey fringes as well as spin echo signals and infer a reversible dephasing time $T_2^\\ast=0.6$ ms and an irreversible dephasing time $T_2^\\prime=3.7$ ms. By theoretically modelling the signals, we find that, for our experimental parameters, $T_2^\\ast$ and $T_2^\\prime$ are limited by the finite initial temperature of the atomic ensemble and the heating rate, respectively. Our results represent a fundamental step towards establishing nanofiber-based traps for cold atoms as a building block in an optical fiber quantum network.

  3. Coherence Properties of Nanofiber-Trapped Cesium Atoms

    Reitz, D.; Sayrin, C.; Mitsch, R.; Schneeweiss, P.; Rauschenbeutel, A.

    2013-06-01

    We experimentally study the ground state coherence properties of cesium atoms in a nanofiber-based two-color dipole trap, localized ˜200nm away from the fiber surface. Using microwave radiation to coherently drive the clock transition, we record Ramsey fringes as well as spin echo signals and infer a reversible dephasing time of T2*=0.6ms and an irreversible dephasing time of T2'=3.7ms. By modeling the signals, we find that, for our experimental parameters, T2* and T2' are limited by the finite initial temperature of the atomic ensemble and the heating rate, respectively. Our results represent a fundamental step towards establishing nanofiber-based traps for cold atoms as a building block in an optical fiber quantum network.

  4. Influence of realistic atom wall potentials in quantum reflection traps

    Madroñero, Javier; Friedrich, Harald

    2007-02-01

    We study the influence of atom-surface interactions close to the surface on the confinement properties in a recently proposed model [A. Jurisch and H. Friedrich, Phys. Lett. A 349, 230 (2006)] for quantum reflection traps and test the reliability of the sharp-step approximation used there. Accurate numerical calculations show a dependence of the surviving particle fraction on characteristic potential lengths determined by the behavior of the interaction in the limits r→0 and r→∞ of the atom-surface distance r . For interactions dominated by the retarded potential proportional to 1/r4 we find that the simplified sharp-step potential reproduces the behavior of the trapped atoms well, both qualitatively and quantitatively.

  5. Determination of antimony by using tungsten trap atomic absorption spectrometry

    An electrically heated tungsten coil was used as a trap in the determination of antimony. The technique consists of three steps. Initially, SbH3 is formed by hydride generation procedure; then the analyte species in vapor form are transported to W-coil trap heated at 370 deg. C. Following the preconcentration step, the trap is heated to 895 deg. C; analyte species are revolatilized and transported to the flame-heated quartz atom cell where atomization and the formation of signal take place. The experimental parameters were optimized both for trap and no-trap studies. The most important experimental parameters are concentrations of HCl and NaBH4 solutions, H2 and Ar gas flow rates, and collection and revolatilization temperatures of W-coil. Accuracy was tested using a certified reference material, waste water EU-L-1. Limit of detection for the system is 16 ng l-1 using a sample of 36 ml collected in 4.0 min. Enhancement factor in sensitivity was 17

  6. Arrays of microscopic magnetic traps for cold atoms and their applications in atom optics

    印建平; 高伟建; 胡建军

    2002-01-01

    A single microscopic magnetic trap for neutral atoms using planar current-carrying wires was proposed and studiedtheoretically by Weinstein et al. In this paper, we propose three structures of composite current-carrying wires to provide1D, 2D and 3D arrays of microscopic magnetic traps for cold alkali atoms. The spatial distributions of magnetic fieldsgenerated by these structures are calculated and the field gradient and curvature in each single microtrap are analysed.Our study shows that arrays of microscopic magnetic traps can be used to provide 1D, 2D or 3D atomic magneticlattices, and even to realize 1D, 2D and 3D arrays of magneto-optical traps, and so on.

  7. Single atom detection of calcium isotopes by atom trap trace analysis

    Hoekstra, S; Morgenstern, R; Wilschut, H W; Hoekstra, R

    2005-01-01

    We demonstrate a combination of an isotopically purified atom beam and a magneto-optical trap which enables the single atom detection of all stable isotopes of calcium (40, 42, 43, 44, 46 and 48). These isotopes range in abundance from 96.9 % (40Ca) to 0.004 (46Ca). The trap is loaded from an atomic beam which is decelerated in a Zeeman slower and subsequently deflected over an angle of 30 degrees by optical molasses. The isotope selectivity of the Zeeman slower and the deflection stage is investigated experimentally and compared with Monte Carlo simulations.

  8. Atomic physics experiments with trapped and cooled highly charged ions

    Kluge, H -J; Winters, D F A

    2007-01-01

    Trapping and cooling techniques have become very important for many fundamental experiments in atomic physics. When applied to highly charged ions confined in Penning traps, these procedures are very effective for testing quantum electrodynamics in extreme electromagnetic fields produced by heavy highly charged ions such as uranium U$^{91+}$. In addition, fundamental constants or nuclear ground state properties can be determined with high accuracy in these simple systems. Finally, by studying a single trapped radioactive ion, its nuclear decay can be studied in detail by observing the disappearance of the signal of the mother and the appearance of that of the daughter isotope. Such experiments on highly charged ions at extremely low energy will become possible by the HITRAP facility which is currently being built up at GSI. Also the future Facility for Antiproton and Ion Research (FAIR) will be briefly described which is expected to be operational by 2014.

  9. Extremely nonlocal optical nonlinearities in atoms trapped near a waveguide

    Shahmoon, Ephraim; Stimming, Hans Peter; Mazets, Igor; Kurizki, Gershon

    2014-01-01

    Nonlinear optical phenomena are typically local. Here we predict the possibility of highly nonlocal optical nonlinearities for light propagating in atomic media trapped near a nano-waveguide, where long-range interactions between the atoms can be tailored. When the atoms are in an electromagnetically-induced transparency configuration, the atomic interactions are translated to long-range interactions between photons and thus to highly nonlocal optical nonlinearities. We derive and analyze the governing nonlinear propagation equation, finding a roton-like excitation spectrum for light and the emergence of long-range order in its output intensity. These predictions open the door to studies of unexplored wave dynamics and many-body physics with highly-nonlocal interactions of optical fields in one dimension.

  10. Nonperturbative and perturbative treatments of parametric heating in atom traps

    Jauregui, R.

    2001-01-01

    We study the quantum description of parametric heating in harmonic potentials both nonperturbatively and perturbatively, having in mind atom traps. The first approach establishes an explicit connection between classical and quantum descriptions; it also gives analytic expressions for properties such as the width of fractional frequency parametric resonances. The second approach gives an alternative insight into the problem and can be directly extended to take into account nonlinear effects. T...

  11. Spin diffusion in trapped clouds of strongly interacting cold atoms

    Bruun, G. M.; Pethick, C.J.

    2011-01-01

    We show that puzzling recent experimental results on spin diffusion in a strongly interacting atomic gas may be understood in terms of the predicted spin diffusion coefficient for a generic strongly interacting system. Three important features play a central role: a) Fick's law for diffusion must be modified to allow for the trapping potential, b) the diffusion coefficient is inhomogeneous, due to the density variations in the cloud and c) the diffusion approximation fails in the outer parts ...

  12. High contrast atomic magnetometer based on coherent population trapping

    We present an experimental and theoretical investigation of the coherent population trapping (CPT) resonance excited on the D1 line of 87Rb atoms by bichromatic linearly polarized laser light. The experimental results show that a lin ‖ lin transition scheme is a promising alternative to the conventional circular—circular transition scheme for an atomic magnetometer. Compared with the circular light transition scheme, linear light accounts for high-contrast transmission resonances, which makes this excitation scheme promising for high-sensitivity magnetometers. We also use linear light and circular light to detect changes of a standard magnetic field, separately. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  13. Coherent Population Trapping-Ramsey Interference in Cold Atoms

    CHEN Xi; YANG Guo-Qing; WANG Jin; ZHAN Ming-Sheng

    2010-01-01

    @@ We demonstrate an experimental observation of coherent population trapping-Ramsey interference in cold 87Rb atoms by employing the time-domain separated oscillatory fields' method. The interference fringe with line width of 80Hz is obtained. We propose a novel method to measure the cold atom number. The measurement is insensitive to the pump beam intensity, the single photon detuning and even the initial state population. We use this method to normalize the interference signal and to improve the signal-to-noise ratio significantly.

  14. Time-Optimal Frictionless Atom Cooling in Harmonic Traps

    Stefanatos, Dionisis; Li, Jr-Shin

    2012-01-01

    Frictionless atom cooling in harmonic traps is formulated as a time-optimal control problem and a synthesis of optimal controlled trajectories is obtained. This work has already been used to determine the minimum time for transition between two thermal states and to show the emergence of the third law of classical thermodynamics from quantum thermodynamics. It can also find application in the fast adiabatic-like expansion of Bose-Einstein condensates, with possible applications in atom interferometry. This paper is based on our recently published article in SIAM J. Control Optim.

  15. Atom trapping in a bottle beam created by a diffractive optical element

    Ivanov, V V; Saffman, M; Kemme, S A; Ellis, A R; Brady, G R; Wendt, J R; Biedermann, G W; Samora, S

    2013-01-01

    A diffractive optical element (DOE) has been fabricated for creating blue detuned atomic bottle beam traps. The DOE integrates several diffractive lenses for trap creation and imaging of atomic fluorescence. We characterize the performance of the DOE and demonstrate trapping of cold Cesium atoms inside a bottle beam.

  16. Effects of the Centre-of-Mass Motion on the Population Trapping of Ultracold Atoms

    熊锦; 张智明

    2003-01-01

    We investigate the effects of the atomic centre-of-mass motion on atomic population trapping in a two-mode micromaser injected with ultracold A-type three-level atoms.We find that in the mazer regime(the case in which the atomic kinetic energy is much smaller than the atom-field interaction energy),the interplay between reflection and transmission of the ultracold atom leads to the destruction of the atomic population trapping.

  17. Thermally stable single-atom platinum-on-ceria catalysts via atom trapping.

    Jones, John; Xiong, Haifeng; DeLaRiva, Andrew T; Peterson, Eric J; Pham, Hien; Challa, Sivakumar R; Qi, Gongshin; Oh, Se; Wiebenga, Michelle H; Pereira Hernández, Xavier Isidro; Wang, Yong; Datye, Abhaya K

    2016-07-01

    Catalysts based on single atoms of scarce precious metals can lead to more efficient use through enhanced reactivity and selectivity. However, single atoms on catalyst supports can be mobile and aggregate into nanoparticles when heated at elevated temperatures. High temperatures are detrimental to catalyst performance unless these mobile atoms can be trapped. We used ceria powders having similar surface areas but different exposed surface facets. When mixed with a platinum/aluminum oxide catalyst and aged in air at 800°C, the platinum transferred to the ceria and was trapped. Polyhedral ceria and nanorods were more effective than ceria cubes at anchoring the platinum. Performing synthesis at high temperatures ensures that only the most stable binding sites are occupied, yielding a sinter-resistant, atomically dispersed catalyst. PMID:27387946

  18. Thermally stable single-atom platinum-on-ceria catalysts via atom trapping

    Jones, John; Xiong, Haifeng; DelaRiva, Andrew; Peterson, Eric J.; Pham, Hien; Challa, Sivakumar R.; Qi, Gongshin; Oh, Se H.; Wiebenga, Michelle H.; Pereira Hernandez, Xavier I.; Wang, Yong; Datye, Abhaya K.

    2016-07-08

    Catalysts based on single atoms of scarce precious metals can lead to more efficient use through enhanced reactivity and selectivity. However, single atoms on catalyst supports can be mobile and aggregate into nanoparticles when heated at elevated temperatures. High temperatures are detrimental to catalyst performance unless these mobile atoms can be trapped. We used ceria powders having similar surface areas but different exposed surface facets. When mixed with a platinum/ aluminum oxide catalyst and aged in air at 800°C, the platinum transferred to the ceria and was trapped. Polyhedral ceria and nanorods were more effective than ceria cubes at anchoring the platinum. Performing synthesis at high temperatures ensures that only the most stable binding sites are occupied, yielding a sinter-resistant, atomically dispersed catalyst.

  19. Portable atomic frequency standard based on coherent population trapping

    Shi, Fan; Yang, Renfu; Nian, Feng; Zhang, Zhenwei; Cui, Yongshun; Zhao, Huan; Wang, Nuanrang; Feng, Keming

    2015-05-01

    In this work, a portable atomic frequency standard based on coherent population trapping is designed and demonstrated. To achieve a portable prototype, in the system, a single transverse mode 795nm VCSEL modulated by a 3.4GHz RF source is used as a pump laser which generates coherent light fields. The pump beams pass through a vapor cell containing atom gas and buffer gas. This vapor cell is surrounded by a magnetic shield and placed inside a solenoid which applies a longitudinal magnetic field to lift the Zeeman energy levels' degeneracy and to separate the resonance signal, which has no first-order magnetic field dependence, from the field-dependent resonances. The electrical control system comprises two control loops. The first one locks the laser wavelength to the minimum of the absorption spectrum; the second one locks the modulation frequency and output standard frequency. Furthermore, we designed the micro physical package and realized the locking of a coherent population trapping atomic frequency standard portable prototype successfully. The short-term frequency stability of the whole system is measured to be 6×10-11 for averaging times of 1s, and reaches 5×10-12 at an averaging time of 1000s.

  20. Coherent population trapping in a Raman atom interferometer

    Cheng, Bing; Merlet, Sébastien; Santos, Franck Pereira dos

    2016-01-01

    We investigate the effect of coherent population trapping (CPT) in an atom inter-ferometer gravimeter based on the use of stimulated Raman transitions. We find that CPT leads to significant phase shifts, of order of a few mrad, which may compromise the accuracy of inertial measurements. We show that this effect is rejected by the k-reversal technique, which consists in averaging inertial measurements performed with two opposite orientations of the Raman wavevector k, provided that internal states at the input of the interferometer are kept identical for both configurations.

  1. Coherent population trapping in a Raman atom interferometer

    Cheng, B.; Gillot, P.; Merlet, S.; Pereira Dos Santos, F.

    2016-06-01

    We investigate the effect of coherent population trapping (CPT) in an atom interferometer gravimeter based on the use of stimulated Raman transitions. We find that CPT leads to significant phase shifts, on the order of a few mrad, which may compromise the accuracy of inertial measurements. We show that this effect is rejected by the k -reversal technique, which consists of averaging inertial measurements performed with two opposite orientations of the Raman wave vector k , provided that internal states at the input of the interferometer are kept identical for both configurations.

  2. Stability of a trapped atom clock on a chip

    Szmuk, Ramon; Maineult, Wilfried; Reichel, Jakob; Rosenbusch, Peter

    2015-01-01

    We present a compact atomic clock interrogating ultracold 87Rb magnetically trapped on an atom chip. Very long coherence times sustained by spin self-rephasing allow us to interrogate the atomic transition with 85% contrast at 5 s Ramsey time. The clock exhibits a fractional frequency stability of $5.8\\times 10^{-13}$ at 1 s and is likely to integrate into the $1\\times10^{-15}$ range in less than a day. A detailed analysis of 7 noise sources explains the measured frequency stability. Fluctuations in the atom temperature (0.4 nK shot-to-shot) and in the offset magnetic field ($5\\times10^{-6}$ relative fluctuations shot-to-shot) are the main noise sources together with the local oscillator, which is degraded by the 30% duty cycle. The analysis suggests technical improvements to be implemented in a future second generation set-up. The results demonstrate the remarkable degree of technical control that can be reached in an atom chip experiment.

  3. Rapid Cooling to Quantum Degeneracy with Dynamically Shaped Atom Traps

    Roy, Richard; Bowler, Ryan; Gupta, Subhadeep

    2016-01-01

    We report on a general method for the rapid production of quantum degenerate gases. Using 174Yb, we achieve an experimental cycle time as low as (1.6-1.8) s for the production of Bose-Einstein condensates (BECs) of (0.5-1) x 10^5 atoms. While laser cooling to 30\\muK proceeds in a standard way, evaporative cooling is highly optimized by performing it in an optical trap that is dynamically shaped by utilizing the time-averaged potential of a single laser beam moving rapidly in one dimension. We also produce large (>10^6) atom number BECs and successfully model the evaporation dynamics over more than three orders of magnitude in phase space density. Our method provides a simple and general approach to solving the problem of long production times of quantum degenerate gases.

  4. Trapping and cooling cesium atoms in a speckle field

    We present the results of two experiments where cold cesium atoms are trapped in a speckle field. In the first experiment, a YAG laser creates the speckle pattern and induces a far-detuned dipole potential which is a nearly-conservative potential. Localization of atoms near the intensity maxima of the speckle field is observed. In a second experiment we use two counterpropagating laser beams tuned close to a resonance line of cesium and in the lin perpendicular to lin configuration, one of them being modulated by a holographic diffuser that creates the speckle field. Three-dimensional cooling is observed. Variations of the temperature and of the spatial diffusion coefficient with the size of a speckle grain are presented. (orig.)

  5. Magneto-optical trap for neutral mercury atoms

    Due to its low sensitivity to blackbody radiation, neutral mercury is a good candidate for the most accurate optical lattice clock. Here we report the observation of cold mercury atoms in a magneto-optical trap (MOT). Because of the high vapor pressure at room temperature, the mercury source and the cold pump were cooled down to −40 °C and −70 °C, respectively, to keep the science chamber in an ultra-high vacuum of 6 × 10−9 Pa. Limited by the power of the UV cooling laser, the one beam folded MOT configuration was adopted, and 1.5×105 Hg-202 atoms were observed by fluorescence detection. (rapid communication)

  6. Magneto-optical trap for neutral mercury atoms

    Liu Hong-Li; Yin Shi-Qi; Liu Kang-Kang; Qian Jun; Xu Zhen; Hong Tao; Wang Yu-Zhu

    2013-01-01

    Due to its low sensitivity to blackbody radiation,neutral mercury is a good candidate for the most accurate optical lattice clock.Here we report the observation of cold mercury atoms in a magneto-optical trap (MOT).Because of the high vapor pressure at room temperature,the mercury source and the cold pump were cooled down to-40 ℃ and-70 ℃,respectively,to keep the science chamber in an ultra-high vacuum of 6× 10-9 Pa.Limited by the power of the UV cooling laser,the one beam folded MOT configuration was adopted,and 1.5× 105 Hg-202 atoms were observed by fluorescence detection.

  7. Evaporative Cooling of Atoms to Quantum Degeneracy in an Optical Dipole Trap

    We discuss our experimental results on forced evaporative cooling of cold rubidium 87Rb atoms to quantum degeneracy in an Optical Dipole Trap. The atoms are first trapped and cooled in a magneto-optical trap (MOT) loaded from a continuous beam of cold atoms. More than 1010 atoms are trapped in the MOT and then about 108 atoms are transferred to a Quasi-Electrostatic Trap (QUEST) formed by tightly focused CO2 laser (λ = 10.6μm) beams intersecting at their foci in an orthogonal configuration in the horizontal plane. Before loading the atoms into the dipole trap, the phase-space density of the atomic ensemble was increased making use of sub-doppler cooling at large detuning and the temporal dark MOT technique. In a MOT the phase-space density of the atomic ensemble is six orders of magnitude less than what is required to achieve quantum degeneracy. After transferring atoms into the dipole trap efficiently, phase-space density increases by a factor of 103. Further increase in phase-space density to quantum degeneracy is achieved by forced evaporative cooling of atoms in the dipole trap. The evaporative cooling process involves a gradual reduction of the trap depth by ramping down the trapping laser intensity over a second. The temperature of the cold atomic cloud was measured by time-of-flight (TOF) technique. The spatial distribution of the atoms is measured using absorption imaging. We report results of evaporative cooling in a single beam and in a crossed double-beam dipole traps. Due to the large initial phase space density, and large initial number of atoms trapped, the quantum phase transition occurs after about 600 ms of evaporative cooling in our optimized crossed dipole trap

  8. Holographic optical traps for atom-based topological Kondo devices

    Buccheri, F.; Bruce, G. D.; Trombettoni, A.; Cassettari, D.; Babujian, H.; Korepin, V. E.; Sodano, P.

    2016-07-01

    The topological Kondo (TK) model has been proposed in solid-state quantum devices as a way to realize non-Fermi liquid behaviors in a controllable setting. Another motivation behind the TK model proposal is the demand to demonstrate the quantum dynamical properties of Majorana fermions, which are at the heart of their potential use in topological quantum computation. Here we consider a junction of crossed Tonks–Girardeau gases arranged in a star-geometry (forming a Y-junction), and we perform a theoretical analysis of this system showing that it provides a physical realization of the TK model in the realm of cold atom systems. Using computer-generated holography, we experimentally implement a Y-junction suitable for atom trapping, with controllable and independent parameters. The junction and the transverse size of the atom waveguides are of the order of 5 μm, leading to favorable estimates for the Kondo temperature and for the coupling across the junction. Since our results show that all the required theoretical and experimental ingredients are available, this provides the demonstration of an ultracold atom device that may in principle exhibit the TK effect.

  9. Optical control of a magneto-optical trap for cesium atoms

    Loading of a magneto-optical trap for cesium atoms is studied in presence of an auxiliary (control) laser beam that is tuned to 6s1/2 F=4 → 6p3/2 F' = 3,4,5 hyperfine manifold. It is shown that the steady state number of trapped atoms is enhanced or suppressed depending on the frequency, intensity and position of the control beam in the trap. The overall result is to provide an ability to optically control the number of trapped atoms without having to change the parameters of the trap. Detailed parametric studies of the control laser assisted optical manipulation of a MOT are presented

  10. An atomic beam fluorescence locked magneto-optical trap for krypton atoms

    We report here an atomic beam loaded magneto-optical trap (MOT) for metastable krypton atoms in which the fluorescence signal from the atomic beam is used to lock the cooling laser frequency. The fluorescence signal is generated by exciting the metastable krypton atomic beam using a probe laser beam (i.e. part of the cooling laser beam) intersecting the atomic beam at an angle. A spectral shift in the fluorescence signal can be achieved by varying the angle between the probe laser beam and the atomic beam to obtain the desired frequency detuning to lock the cooling laser frequency. This has been used to optimize the number of cold atoms in the MOT. The dependence of the peak height and slope of the atomic beam fluorescence (ABF) locking signal on the RF power in the discharge tube and pressure in the observation chamber of the setup has been studied to correlate its effect on the number of atoms in the MOT. (paper)

  11. Laser Cooling without Repumping: A Magneto-Optical Trap for Erbium Atoms

    We report on a novel mechanism that allows for strong laser cooling of atoms that do not have a closed cycling transition. This mechanism is observed in a magneto-optical trap (MOT) for erbium, an atom with a very complex energy level structure with multiple pathways for optical-pumping losses. We observe surprisingly high trap populations of over 106 atoms and densities of over 1011 atoms cm-3, despite the many potential loss channels. A model based on recycling of metastable and ground state atoms held in the quadrupole magnetic field of the trap explains the high trap population, and agrees well with time-dependent measurements of MOT fluorescence. The demonstration of trapping of a rare-earth atom such as erbium opens a wide range of new possibilities for practical applications and fundamental studies with cold atoms

  12. Box traps on an atom chip for one-dimensional quantum gases

    van Es, J J P; van Amerongen, A H; Rétif, C; Whitlock, S; van Druten, N J

    2009-01-01

    We present the implementation of tailored trapping potentials for ultracold gases on an atom chip. We realize highly elongated traps with box-like confinement along the long, axial direction combined with conventional harmonic confinement along the two radial directions. The design, fabrication and characterization of the atom chip and the box traps is described. We load ultracold ($\\lesssim1 \\mu$K) clouds of $^{87}$Rb in a box trap, and demonstrate Bose-gas focusing as a means to characterize these atomic clouds in arbitrarily shaped potentials. Our results show that box-like axial potentials on atom chips are very promising for studies of one-dimensional quantum gases.

  13. Observation of cooperatively enhanced atomic dipole forces from NV centers in optically trapped nanodiamonds

    Juan, M L; Besga, B; Brennen, G; Molina-Terriza, G; Volz, T

    2015-01-01

    Since the early work by Ashkin in 1970, optical trapping has become one of the most powerful tools for manipulating small particles, such as micron sized beads or single atoms. The optical trapping mechanism is based on the interaction energy of a dipole and the electric field of the laser light. In atom trapping, the dominant contribution typically comes from the allowed optical transition closest to the laser wavelength, whereas for mesoscopic particles it is given by the bulk polarizability of the material. These two different regimes of optical trapping have coexisted for decades without any direct link, resulting in two very different contexts of applications: one being the trapping of small objects mainly in biological settings, the other one being dipole traps for individual neutral atoms in the field of quantum optics. Here we show that for nanoscale diamond crystals containing artificial atoms, so-called nitrogen vacancy (NV) color centers, both regimes of optical trapping can be observed at the same...

  14. Integrated Optical Dipole Trap for Cold Neutral Atoms with an Optical Waveguide Coupler

    Lee, J; Mittal, S; Dagenais, M; Rolston, S L

    2013-01-01

    An integrated optical dipole trap uses two-color (red and blue-detuned) traveling evanescent wave fields for trapping cold neutral atoms. To achieve longitudinal confinement, we propose using an integrated optical waveguide coupler, which provides a potential gradient along the beam propagation direction sufficient to confine atoms. This integrated optical dipole trap can support an atomic ensemble with a large optical depth due to its small mode area. Its quasi-TE0 waveguide mode has an advantage over the HE11 mode of a nanofiber, with little inhomogeneous Zeeman broadening at the trapping region. The longitudinal confinement eliminates the need for a 1-D optical lattice, reducing collisional blockaded atomic loading, potentially producing larger ensembles. The waveguide trap allows for scalability and integrability with nano-fabrication technology. We analyze the potential performance of such integrated atom traps.

  15. Highly uniform holographic microtrap arrays for single atom trapping using a feedback optimization of in-trap fluorescence measurements.

    Tamura, Hikaru; Unakami, Tomoyuki; He, Jun; Miyamoto, Yoko; Nakagawa, Ken'ichi

    2016-04-18

    We report on the novel optimization method to realize highly uniform microtrap arrays for single atom trapping with a spatial light modulator (SLM). This method consists of two iterative feedback loops with the measurements of both diffracted light intensities and in-trap fluorescence intensities from each microtrap. By applying this method to the single 87Rb atom trapping, we can reduce the variance of trap depths from 20.8% to 1.7% for 4 × 4 square arrays and less than 4% for various arrays with up to 62 sites. The detection error of individual single atoms is also reduced from 1.7% to 0.0054% on average. PMID:27137252

  16. Experimental single-impulse magnetic focusing of launched cold atoms

    Smith, D A; Hughes, I G; Pritchard, M J; Arnold, Aidan S.; Hughes, Ifan G.; Pritchard, Matthew J.; Smith, David A.

    2007-01-01

    Three-dimensional magnetic focusing of cold atoms with a single magnetic impulse has been observed for the first time. We load 7x10^7 85-Rb atoms into a magneto-optical trap, precool the atoms with optical molasses, then use moving molasses to launch them vertically through 20.5cm to the apex of flight. In transit the atoms are optically pumped, prior to the single magnetic lens impulse that occurs 16.5cm above the MOT. Fluorescence images at the apex of flight characterise the widths of the focussed cloud. Results were obtained for four different configurations of the baseball lens, which tuned the relationship between the axial and radial frequencies of the lens. Compact focused clouds were seen for all four configurations.

  17. Comparison of hyperfine anomalies in the 5S_{1/2} and 6S_{1/2} levels of ^{85}Rb and ^{87}Rb

    Galvan, A Perez; Orozco, L A; Gómez, E; Lange, A D; Baumer, F; Sprouse, G D

    2008-01-01

    We observe a hyperfine anomaly in the measurement of the hyperfine splitting of the 6S_{1/2} excited level in rubidium. We perform two step spectroscopy using the 5S_{1/2}->5P_{1/2}->6S_{1/2} excitation sequence. We measure the splitting of the 6S1/2 level and obtain for the magnetic dipole constants of ^{85}Rb and ^{87}Rb A = 239.18(4) MHz and A=807.66(8) MHz, respectively. The hyperfine anomaly difference of_{87}delta_{85}=-0.0036(2) comes from the Bohr Weisskopf effect: a correction to the point interaction between the finite nuclear magnetization and the electrons, and agrees with that obtained in the 5S_{1/2} ground state.

  18. Determination of lead traces in water and liqueurs by derivative atom trapping flame atomic absorption spectrometry

    Sun, H. [Department of Chemistry, Hebei University, Baoding, 071002 (China); Yang Lili [Department of Chemistry, Hebei University, Baoding, 071002 (China); Zhang Deqiang [Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing (China); Wang Weixiao [Department of Chemistry, Hebei University, Baoding, 071002 (China); Sun Jianmin [Department of Chemistry, Hebei University, Baoding, 071002 (China)

    1997-07-01

    A new method for the direct determination of lead traces using derivative atom trapping flame atomic absorption spectrometry (DAT-FAAS) with an improved water-cooled stainless steel trapping equipment in an air-acetylene flame was investigated. The optimum conditions concerning the sensitivity were studied. For a 1 min collection, the characteristic concentration (given as derivative absorbance of 0.0044) and the detection limit (3s) were 1.4 ng/mL and 0.27 ng/mL, respectively. This is 361 and 74-fold better than those of the conventional flame atomic absorption spectrometry (FAAS) and comparable to those of graphite furnace atomic absorption spectrometry (GFAAS). The detection limit and sensitivity of DAT-FAAS for a 3 min collection time were 2 and 3 orders of magnitude higher than those of conventional FAAS. The present method was applied to the determination of lead in water and liqueur samples with a recovery range of 94-108% and a relative standard deviation of 3.5-5.6%. (orig.). With 5 figs., 5 tabs.

  19. Atomic ion clock with two ion traps, and method to transfer ions

    Prestage, John D. (Inventor); Chung, Sang K. (Inventor)

    2011-01-01

    An atomic ion clock with a first ion trap and a second ion trap, where the second ion trap is of higher order than the first ion trap. In one embodiment, ions may be shuttled back and forth from one ion trap to the other by application of voltage ramps to the electrodes in the ion traps, where microwave interrogation takes place when the ions are in the second ion trap, and fluorescence is induced and measured when the ions are in the first ion trap. In one embodiment, the RF voltages applied to the second ion trap to contain the ions are at a higher frequency than that applied to the first ion trap. Other embodiments are described and claimed.

  20. Optical trap potential control in N-type four level atoms by femtosecond Gaussian pulses

    Chakraborty, Subhadeep

    2014-01-01

    In this work we present a scheme to control the optical dipole trap potential in an N-type four-level atomic system by using chirped femtosecond Gaussian pulses. The spatial size of the trap can be well controlled by tuning the beam waist of the Gaussian pulse and the detuning frequency. The trapping potential splits with increasing Rabi frequency about the center of the trap, a behavior analogous to the one observed experimentally in the context of trapping of nanoparticles with femtosecond pulses. An attempt is made to explain the physics behind this phenomenon by studying the spatial probability distribution of the atomic populations.

  1. Dynamics in a two-level atom magneto-optical trap

    Alkaline-earth-metal atoms present an ideal platform for exploring magneto-optic trap (MOT) dynamics, enabling unique and definitive tests of laser cooling and trapping mechanisms. We have measured the trapping beam intensity, detuning, magnetic-field gradient, trap density, and lifetime dependence of the spring constant κ and damping coefficient α for a 1S0-1P188Sr MOT by fitting the oscillatory response of the atom cloud to a step-function force. We find that the observed behavior of κ and α provide a unified and consistent picture of trap dynamics that agrees with Doppler cooling theory at the level of 10%. Additionally, we demonstrate that the trapped atom temperature can be determined directly from measured value of κ and the trap size, in excellent agreement with free-expansion temperature measurements. However, the experimentally determined temperature is much higher than Doppler cooling theory, implying significant additional heating mechanisms

  2. A two-dimensional lattice of blue detuned atom traps using a projected Gaussian beam array

    Piotrowicz, M J; Maller, K; Li, G; Zhang, S; Isenhower, L; Saffman, M

    2013-01-01

    We describe a new type of blue detuned optical lattice for atom trapping which is intrinsically two dimensional, while providing three-dimensional atom localization. The lattice is insensitive to optical phase fluctuations since it does not depend on field interference between distinct optical beams. The array is created using a novel arrangement of weakly overlapping Gaussian beams that creates a two-dimensional array of dark traps which are suitable for magic trapping of ground and Rydberg states. We analyze the spatial localization that can be achieved and demonstrate trapping and detection of single Cs atoms in 6 and 49 site two-dimensional arrays.

  3. Bichromatic state-insensitive trapping of cold133Cs-87Rb atomic mixtures

    Metbulut, M. M.; Renzoni, F.

    2015-12-01

    We investigate simultaneous state-insensitive trapping of a mixture of two different atomic species, Caesium and Rubidium. The magic wavelengths of the Caesium and Rubidium atoms are different, $935.6$ nm and $789.9$ nm respectively, thus single-frequency simultaneous state-insensitive trapping is not possible. We thus identify bichromatic trapping as a viable approach to tune the two magic wavelengths to a common value. Correspondingly, we present several common magic wavelength combinations appropriate for simultaneous state-insensitive trapping of the two atomic species.

  4. Inhomogeneous broadening of optical transitions of 87Rb atoms in an optical nanofiber trap

    Lee, J; Hoffman, J E; Orozco, L A; Rolston, S L

    2014-01-01

    We experimentally demonstrate optical trapping of 87Rb atoms using a two-color evanescent field around an optical nanofiber. In our trapping geometry, a blue-detuned traveling wave whose polarization is nearly parallel to the polarization of a red-detuned standing wave produce significant vector light shifts that lead to broadening of the absorption profile of a near-resonant beam at the trapping site. A model that includes scalar, vector, and tensor light shifts of the probe transition $5S_{1/2}$-$5P_{3/2}$ from the trapping beams; weighted by the temperature-dependent position of the atoms in the trap qualitatively describe the observed asymmetric profile, and explained differences with previous experiments that used Cs atoms. The model provides a consistent way to extract the number of atoms in the trap.

  5. Accelerated Thermalisation of 39K atoms in a Magnetic Trap with Superimposed Optical Potential

    Nath, Dipankar; Rajalakshmi, G; Unnikrishnan, C S

    2013-01-01

    We report the rapid accelerated thermalisation of Potassium 39 K atoms loaded in a magnetic trap, in the presence of a single dipole trap beam. More than an order of magnitude reduction in the thermalisation time, to less than a second, is observed with the focused off- resonant beam occupying only 0.01% of the volume of the magnetic trap. The cold atoms are loaded from a Magneto-Optical Trap(MOT) of 39 K that has gone through a compressed MOT and sub-Doppler cooling stage. The atoms are prepared in the magnetically stretched |F = 2, mF = 2> state prior to loading into the hybrid trap. We also report a direct loading of 39 K atoms, prepared in the state |F = 1>, into a single beam dipole trap.

  6. 3D modeling of magnetic atom traps on type-II superconductor chips

    Magnetic traps for cold atoms have become a powerful tool in cold atom physics and condensed matter research. The traps on superconducting chips allow one to increase the trapped atom lifetime and coherence time by decreasing the thermal noise by several orders of magnitude compared to that of the typical normal-metal conductors. A thin superconducting film in the mixed state is, usually, the main element of such a chip. Using a finite element method to analyze thin film magnetization and transport current in type-II superconductivity, we study magnetic traps recently employed in experiments. The proposed approach allows us to predict important characteristics of the magnetic traps (their depth, shape, distance from the chip surface, etc) that are necessary when designing magnetic traps in cold atom experiments. (paper)

  7. Hexapole-compensated magneto-optical trap on a mesoscopic atom chip

    Jöllenbeck, S.; Mahnke, J.; Randoll, R.;

    2011-01-01

    Magneto-optical traps on atom chips are usually restricted to small atomic samples due to a limited capture volume caused primarily by distorted field configurations. Here we present a magneto-optical trap based on a millimeter-sized wire structure which generates a magnetic field with minimized...

  8. Bichromatic State-Insensitive Trapping of Cold 133Cs-87Rb Atomic Mixtures

    Metbulut, M. M.; Renzoni, F.

    2015-01-01

    We investigate simultaneous state-insensitive trapping of a mixture of two different atomic species, Caesium and Rubidium. The magic wavelengths of the Caesium and Rubidium atoms are different, $935.6$ nm and $789.9$ nm respectively, thus single-frequency simultaneous state-insensitive trapping is not possible. We thus identify bichromatic trapping as a viable approach to tune the two magic wavelengths to a common value. Correspondingly, we present several common magic wavelength combinations...

  9. Nonlinear magneto-optical resonances at D1 excitation of 85Rb and 87Rb in an extremely thin cell

    Auzinsh, M; Gahbauer, F; Jarmola, A; Kalvans, L; Papoyan, A; Sarkisyan, D

    2009-01-01

    Nonlinear magneto-optical resonances have been measured in an extremely thin cell (ETC) for the D1 transition of rubidium in an atomic vapor of natural isotopic composition. All hyperfine transitions of both isotopes have been studied for a wide range of laser power densities, laser detunings, and ETC wall separations. Dark resonances in the laser induced fluorescence (LIF) were observed as expected when the ground state total angular momentum F_g was greater than or equal to the excited state total angular momentum F_e. Unlike the case of ordinary cells, the width and contrast of dark resonances formed in the ETC dramatically depended on the detuning of the laser from the exact atomic transition. A theoretical model based on the optical Bloch equations was applied to calculate the shapes of the resonance curves. The model averaged over the contributions from different atomic velocity groups, considered all neighboring hyperfine transitions, took into account the splitting and mixing of magnetic sublevels in ...

  10. Ultracold atomic collisions in tight harmonic traps: Perturbation theory, ionization losses and application to metastable helium atoms

    Beams, T J; Whittingham, I B

    2004-01-01

    Collisions between tightly confined atoms can lead to ionization and hence to loss of atoms from the trap. We develop second-order perturbation theory for a tensorial perturbation of a spherically symmetric system and the theory is then applied to processes mediated by the spin-dipole interaction. Redistribution and loss mechanisms are studied for the case of spin-polarized metastable helium atoms and results obtained for the five lowest s states in the trap and trapping frequencies ranging from 1 kHz to 10 MHz.

  11. Reconfigurable self-sufficient traps for ultracold atoms based on a superconducting square

    Siercke, M; Zhang, B; Beian, M; Lim, M J; Dumke, R

    2012-01-01

    We report on the trapping of ultracold atoms in the magnetic field formed entirely by persistent supercurrents induced in a thin film type-II superconducting square. The supercurrents are carried by vortices induced in the 2D structure by applying two magnetic field pulses of varying amplitude perpendicular to its surface. This results in a self-sufficient quadrupole trap that does not require any externally applied fields. We investigate the trapping parameters for different supercurrent distributions. Furthermore, to demonstrate possible applications of these types of supercurrent traps we show how a central quadrupole trap can be split into four traps by the use of a bias field.

  12. Nonlinear magneto-optical resonances at D1 excitation of 85Rb and 87Rb in an extremely thin cell

    Nonlinear magneto-optical resonances have been measured in an extremely thin cell (ETC) for the D1 transition of rubidium in an atomic vapor of natural isotopic composition. All hyperfine transitions of both isotopes have been studied for a wide range of laser power densities, laser detunings, and ETC wall separations. Dark resonances in the laser induced fluorescence (LIF) were observed as expected when the ground-state total angular momentum Fg was greater than or equal to the excited-state total angular momentum Fe. Unlike the case of ordinary cells, the width and contrast of dark resonances formed in the ETC dramatically depended on the detuning of the laser from the exact atomic transition. A theoretical model based on the optical Bloch equations was applied to calculate the shapes of the resonance curves. The model, which had been developed previously for ordinary vapor cells, averaged over the contributions from different atomic velocity groups, considered all neighboring hyperfine transitions, took into account the splitting and mixing of magnetic sublevels in an external magnetic field, and included a detailed treatment of the coherence properties of the laser radiation. Such a theoretical approach had successfully described nonlinear magneto-optical resonances in ordinary vapor cells. However, to describe the resonances in the ETC, key parameters such as the ground-state relaxation rate, excited-state relaxation rate, Doppler width, and Rabi frequency had to be modified significantly in accordance with the ETC's unique features. The level of agreement between the measured and calculated resonance curves achieved for the ETC was similar to what could be accomplished for ordinary cells. However, in the case of the ETC, it was necessary to fine-tune parameters such as the background and the Rabi frequency for different transitions, whereas for the ordinary cells, these parameters were identical for all transitions.

  13. Compact atomic clock prototype based on coherent population trapping

    Danet Jean-Marie

    2014-01-01

    Full Text Available Toward the next generations of compact atomic clocks, clocks based on coherent population trapping (CPT offer a very interesting alternative. Thanks to CPT, a quantum interfering process, this technology has made a decisive step in the miniaturization direction. Fractional frequency stability of 1.5x10-10 at 1 s has been demonstrated in commercial devices of a few cm3. The laboratory prototype presented here intends to explore what could be the ultimate stability of a CPT based device. To do so, an original double-Λ optical scheme and a pulsed interrogation have been implemented in order to get a good compromise between contrast and linewidth. A study of two main sources of noise, the relative intensity and the local oscillator (LO noise, has been performed. By designing simple solutions, it led to a new fractional frequency limitation lower than 4x10-13 at 1 s integration. Such a performance proves that such a technology could rival with classical ones as double resonance clocks.

  14. Magneto-Optical Trapping of Ytterbium Atoms with a 398.9 nm Laser

    ZHAO Peng-Yi; XIONG Zhuan-Xian; LIANG Jie; HE Ling-Xiang; LU Bao-Long

    2008-01-01

    We report the realization of ytterbium magneto-optical trap (MOT) operating on the dipole-allowed 1S0 - 1P1 transition at 398.9nm. The MOT is loaded by a slowed atomic beam produced by a Zeeman slower. All seven stable isotopes of Yb atoms could be trapped separately at different laser detuning values. Over 107 174Yb atoms are collected in the MOT, whereas the atom number of fermionic isotope 171Yb is roughly 2.3 × 106 due to a lower abundance. Without the Zeeman slower, the trapped atom numbers are one order of magnitude lower.Both the even and odd isotopes are recognized as excellent candidates of optical clock transition, so the cooling and trapping of ytterbium atoms by the blue MOT is an important step for building an optical clock.

  15. Magneto-optical trapping of ytterbium atoms with a 398.9 nm laser

    We report the realization of ytterbium magneto-optical trap (MOT) operating on the dipole-allowed 1S0-1P1 transition at 398.9 nm. The MOT is loaded by a slowed atomic beam produced by a Zeeman slower. All seven stable isotopes of Yb atoms could be trapped separately at different laser detuning values. Over 107 174Yb atoms are collected in the MOT, whereas the atom number of fermionic isotope 171Yb is roughly 2.3 × 106 due to a lower abundance. Without the Zeeman slower, the trapped atom numbers are one order of magnitude lower. Both the even and odd isotopes are recognized as excellent candidates of optical clock transition, so the cooling and trapping of ytterbium atoms by the blue MOT is an important step for building an optical clock. (authors)

  16. Self-organization effects and light amplification of collective atomic recoil motion in a harmonic trap

    Zhang, L.; Yang, G. J.; Xia, L. X.

    2005-01-01

    Self-organization effects related to light amplification in the collective atomic recoil laser system with the driven atoms confined in a harmonic trap are investigated further. In the dispersive parametric region, our study reveals that the spontaneously formed structures in the phase space contributes an important role to the light amplification of the probe field under the atomic motion being modified by the trap.

  17. Design, fabrication and characterization of tunable external cavity diode laser and atom trapping chips for atomic physics

    Chuang, Ho-Chiao

    External cavity diode laser systems (ECDLs) have been well documented for their suitability in the fields of laser cooling and atom trapping, and are now widely used in optical and atomic physics. A particularly simple implementation of this idea uses feedback from a diffraction grating mounted in the Littrow configuration and the typical size of this laser is quite large (120mmx90mmx90mm). For atom optics, the current atom trapping chips are not in a feedthrough configuration, which makes the chips to glass cell assembly process complicated and the wires and solder areas vulnerable, resulting in an unreliable vacuum seal. Recent experimental realizations of atom optical devices such as atomic waveguides, beam splitters, and on-chip Bose-Einstein condensate (BEC) sources have opened a new field for the development of more complex devices such as, e.g., BEC-based atom transistor. This work focuses on micro/nano fabrication techniques to build three different devices for the miniature BEC system. The research work focuses on the development of new ECDLs, a novel fabrication process of feedthrough atom trapping chips for atomic optics and a fabrication process for atom transistor chips. In the ECDLs part, we describe a new method for constructing a smaller external-cavity diode laser by use of a micromachined silicon flexure and a VHG (Volume Holographic Grating). It is much smaller, inexpensive and easy to build because it is based on simple modifications of a few commercial optical and mechanical components but with a specific silicon flexure design enabled by micro-fabrication technology for the laser frequency tuning. In the feedthrough chips part, we present a novel fabrication process for feedthrough atom trapping chips in atomic condensate optics cells using the copper electroplating to seal the vias. The advantages of using feedthrough atom trapping chips are the simple microfabrication process and reduction of the overall chip area bonded on the glass atom-trapping

  18. Magnetic levitation for effective loading of cold cesium atoms in a crossed dipole trap

    Li, Yuqing; Feng, Guosheng; Xu, Rundong; Wang, Xiaofeng; Wu, Jizhou; Chen, Gang; Dai, Xingcan; Ma, Jie; Xiao, Liantuan; Jia, Suotang

    2015-05-01

    We report a detailed study of effective magnetically levitated loading of cold atoms in a crossed dipole trap: an appropriate magnetic field gradient precisely compensates for the destructive gravitational force of the atoms and an additional bias field simultaneously eliminates the antitrapping potential induced by the magnetic field gradient. The magnetic levitation is required for a large-volume crossed dipole trap to form a shallow but very effective loading potential, making it a promising method for loading and trapping more cold atoms. For cold cesium atoms in the F =3 , m F =3 state prepared by three-dimensional degenerated Raman sideband cooling, a large number of atoms ˜3.2 ×106 have been loaded into a large-volume crossed dipole trap with the help of the magnetic levitation technique. The dependence of the number of atoms loaded and trapped in the dipole trap on the magnetic field gradient and bias field, respectively, is in good agreement with the theoretical analysis. The optimum magnetic field gradient of 31.13 G/cm matches the theoretical value of 31.3 G/cm well. This method can be used to obtain more cold atoms or a large number of Bose-Einstein condensation atoms for many atomic species in high-field seeking states.

  19. Emission spectrum of a harmonically trapped A-type three-level atom

    Guo Hong; Tang Pei

    2013-01-01

    We theoretically investigate the emission spectrum for a ∧-type three-level atom trapped in the node of a standing wave.We show that the atomic center-of-mass motion not only directly affects the peak number,peak position,and peak height in the atomic emission spectrum,but also influences the effects of the cavity field and the atomic initial state on atomic emission spectrum.

  20. Fiber-pigtailed optical tweezer for single-atom trapping and single-photon generation

    Garcia, Sébastien; Hohmann, Leander; Reichel, Jakob; Long, Romain

    2013-01-01

    We demonstrate a miniature, fiber-coupled optical tweezer to trap a single atom. The same fiber is used to trap a single atom and to read out its fluorescence. To obtain a low background level, the tweezer light is chopped, and we measure the influence of the chopping frequency on the atom's lifetime. We use the single atom as a single-photon source at 780 nm and measure the second-order correlation function of the emitted photons. Because of its miniature, robust, fiber-pigtailed design, this tweezer can be implemented in a broad range of experiments where single atoms are used as a resource.

  1. A double-well atom trap for fluorescence detection at the Heisenberg limit

    Stroescu, Ion; Oberthaler, Markus K

    2014-01-01

    We experimentally demonstrate an atom number detector capable of simultaneous detection of two mesoscopic ensembles with single atom resolution. Such a sensitivity is a prerequisite for going beyond quantum metrology with spin-squeezed states. Our system is based on fluorescence detection of atoms in a novel hybrid trap in which a dipole barrier divides a magneto-optical trap into two separated wells. We introduce a noise model describing the various sources contributing to the measurement error and report a limit of up to 500 atoms for the exact determination of the atom number difference.

  2. Resonant interaction of trapped cold atoms with a magnetic cantilever tip

    Montoya, Cris; Geraci, Andrew A; Eardley, Matthew; Moreland, John; Hollberg, Leo; Kitching, John

    2015-01-01

    Magnetic resonance in an ensemble of laser-cooled trapped Rb atoms is excited using a micro- cantilever with a magnetic tip. The cantilever is mounted on a multi-layer chip designed to capture, cool, and magnetically transport cold atoms. The coupling is observed by measuring the loss from a magnetic trap as the oscillating cantilever induces Zeeman state transitions in the atoms. Interfacing cold atoms with mechanical devices could enable probing and manipulating atomic spins with nanometer spatial resolution and single-spin sensitivity, leading to new capabilities in quantum computation, quantum simulation, or precision sensing.

  3. First principles investigation of cluster consisting of hydrogen–helium atoms interstitially-trapped in tungsten

    We evaluate the binding energies of mixed helium and hydrogen clusters consisted of interstitially trapped atoms in bcc tungsten by first-principles calculations based on density functional theories. It is shown that helium-rich interstitially-trapped clusters have the positive binding energies and the low electron-density region expand as the number of helium in the cluster increase. Thus, the helium-rich interstitially trapped clusters can act as a trapping site for hydrogen, and interstitially trapped helium interrupts or disturbs the hydrogen diffusion in tungsten

  4. Observation of single neutral atoms in a large-magnetic-gradient vapour-cell magneto-optical trap

    Wang Jing; He Jun; Qiu Ying; Yang Bao-Dong; Zhao Jiang-Yan; Zhang Tian-Cai; Wang Jun-Min

    2008-01-01

    Single caesium atoms in a large-magnetic-gradient vapour-cell magneto-optical trap have been identified. The trapping of individual atoms is marked by the steps in fluorescence signal corresponding to the capture or loss of single atoms. The typical magnetic gradient is about 29 mT/cm, which evidently reduces the capture rate of magneto-optical trap.

  5. Fast compression of a cold atomic cloud using a blue detuned crossed dipole trap

    Bienaime, Tom; de Lepinay, Laure Mercier; Bellando, Louis; Chabe, Julien; Kaiser, Robin

    2012-01-01

    We present the experimental realization of a compressible blue detuned crossed dipole trap for cold atoms allowing for fast dynamical compression (~ 5 - 10 ms) of 5x10^7 Rubidium atoms up to densities of ~ 10^13 cm^-3. The dipole trap consists of two intersecting tubes of blue-detuned laser light. These tubes are formed using a single, rapidly rotating laser beam which, for sufficiently fast rotation frequencies, can be accurately described by a quasi-static potential. The atomic cloud is compressed by dynamically reducing the trap volume leading to densities close to the Ioffe-Reggel criterion for light localization.

  6. Continuous loading of $^{1}$S$_{0}$ calcium atoms into an optical dipole trap

    Yang, C. Y.; Halder, P.; Appel, O.; Hansen, D.; Hemmerich, A.

    2007-01-01

    We demonstrate an efficient scheme for continuous trap loading based upon spatially selective optical pumping. We discuss the case of $^{1}$S$_{0}$ calcium atoms in an optical dipole trap (ODT), however, similar strategies should be applicable to a wide range of atomic species. Our starting point is a reservoir of moderately cold ($\\approx 300 \\mu$K) metastable $^{3}$P$_{2}$-atoms prepared by means of a magneto-optic trap (triplet-MOT). A focused 532 nm laser beam produces a strongly elongate...

  7. Continuous loading of cold atoms into a Ioffe-Pritchard magnetic trap

    Schmidt, P O; Werner, J; Binhammer, T; Görlitz, A; Pfau, T; Schmidt, Piet O.; Hensler, Sven; Werner, Joerg; Binhammer, Thomas; Goerlitz, Axel; Pfau, Tilman

    2002-01-01

    We present a robust continuous optical loading scheme for a Ioffe-Pritchard (IP) type magnetic trap. Atoms are cooled and trapped in a modified magneto-optical trap (MOT) consisting of a conventional 2D-MOT in radial direction and an axial molasses. The radial magnetic field gradient needed for the operation of the 2D-MOT is provided by the IP trap. A small axial curvature and offset field provide magnetic confinement and suppress spin-flip losses in the center of the magnetic trap without altering the performance of the 2D-MOT. Continuous loading of atoms into the IP trap is provided by radiative leakage from the MOT to a metastable level which is magnetically trapped and decoupled from the MOT light. We are able to accumulate 30 times more atoms in the magnetic trap than in the MOT. The absolute number of $2\\times 10^8$~atoms is limited by inelastic collisions. A model based on rate equations shows good agreement with our data. Our scheme can also be applied to other atoms with similar level structure like ...

  8. Trapping atoms in the evanescent field of laser written wave guides

    Jukic, Dario; Walther, P; Szameit, A; Pohl, T; Götte, J B

    2016-01-01

    We analyze evanescent fields of laser written waveguides and show that they can be used to trap atoms close to the surface of an integrated optical atom chip. In contrast to subwavelength nanofibres it is generally not possible to create a stable trapping potential using only the fundamental modes. This is why we create a stable trapping potential by using two different laser colors, such that the waveguide supports two modes for the blue detuned laser, while for the red detuned light the waveguide has only a single mode. In particular, we study such a two-color trap for Cesium atoms, and calculate both the potential and losses for the set of parameters that are within experimental reach. We also optimize system parameters in order to minimize trap losses due to photon scattering and tunneling to the surface.

  9. Single-atom trapping in holographic 2D arrays of microtraps with arbitrary geometries

    Nogrette, Florence; Ravets, Sylvain; Barredo, Daniel; Béguin, Lucas; Vernier, Aline; Lahaye, Thierry; Browaeys, Antoine

    2014-01-01

    We demonstrate single-atom trapping in two-dimensional arrays of microtraps with arbitrary geometries. We generate the arrays using a Spatial Light Modulator (SLM), with which we imprint an appropriate phase pattern on an optical dipole trap beam prior to focusing. We trap single $^{87}{\\rm Rb}$ atoms in the sites of arrays containing up to $\\sim100$ microtraps separated by distances as small as $3\\;\\mu$m, with complex structures such as triangular, honeycomb or kagome lattices. Using a closed-loop optimization of the uniformity of the trap depths ensures that all trapping sites are equivalent. This versatile system opens appealing applications in quantum information processing and quantum simulation, e.g. for simulating frustrated quantum magnetism using Rydberg atoms.

  10. Bose-Einstein condensation of trapped atoms with dipole interactions

    The path-integral Monte Carlo method is used to simulate dilute trapped Bose gases and to investigate the equilibrium properties at finite temperatures. The quantum particles have a long-range dipole-dipole interaction and a short-range s-wave interaction. Using an anisotropic pseudopotential for the long-range dipolar interaction and a hard-sphere potential for the short-range s-wave interaction, we calculate the energetics and structural properties as a function of temperature and the number of particles. Also, in order to determine the effects of dipole-dipole forces and the influence of the trapping field on the dipolar condensate, we use two cylindrically symmetric harmonic confinements (a cigar-shaped trap and a disk-shaped trap). We find that the net effect of dipole-dipole interactions is governed by the trapping geometry. For a cigar-shaped trap, the net contribution of dipolar interactions is attractive and the shrinking of the density profiles is observed. For a disk-shaped trap, the net effect of long-range dipolar forces is repulsive and the density profiles expand

  11. Magneto-optical trapping of radioactive atoms for test of the fundamental symmetries

    We are planning test experiments of fundamental symmetries based on the intrinsic properties of francium. It is expected that the laser cooling and trapping of francium will produce precision measurements. The pilot experiment using rubidium was performed with the goal of francium trapping. The ion beam generated with a francium ion source was investigated using a Wien filter. Each piece of equipment still must be studied in more detail, and the equipment should be upgraded in order to trap radioactive atoms

  12. Magneto-optical trapping of radioactive atoms for test of the fundamental symmetries

    Kawamura, Hirokazu, E-mail: hirokazu.kawamura.c2@tohoku.ac.jp [Tohoku University, Frontier Research Institute for Interdisciplinary Sciences (Japan); Ando, S.; Aoki, T.; Arikawa, H.; Harada, K.; Hayamizu, T. [Tohoku University, Cyclotron and Radioisotope Center (Japan); Inoue, T. [Tohoku University, Frontier Research Institute for Interdisciplinary Sciences (Japan); Ishikawa, T.; Itoh, M.; Kato, K.; Köhler, L.; Mathis, J.; Sakamoto, K.; Uchiyama, A.; Sakemi, Y. [Tohoku University, Cyclotron and Radioisotope Center (Japan)

    2015-11-15

    We are planning test experiments of fundamental symmetries based on the intrinsic properties of francium. It is expected that the laser cooling and trapping of francium will produce precision measurements. The pilot experiment using rubidium was performed with the goal of francium trapping. The ion beam generated with a francium ion source was investigated using a Wien filter. Each piece of equipment still must be studied in more detail, and the equipment should be upgraded in order to trap radioactive atoms.

  13. Strong Coupling between a Trapped Single Atom and an All-Fiber Cavity.

    Kato, Shinya; Aoki, Takao

    2015-08-28

    We demonstrate an all-fiber cavity quantum electrodynamics system with a trapped single atom in the strong coupling regime. We use a nanofiber Fabry-Perot cavity, that is, an optical nanofiber sandwiched by two fiber-Bragg-grating mirrors. Measurements of the cavity transmission spectrum with a single atom in a state-insensitive nanofiber trap clearly reveal the vacuum Rabi splitting. PMID:26371652

  14. Influence of the atomic-wall collision elasticity on the coherent population trapping resonance shape

    Kazakov, G A; Litvinov, A. N.; Matisov, B. G.; Romanenko, V. I.; Yatsenko, L. P.; Romanenko, A. V.

    2011-01-01

    We studied theoretically a coherent population trapping resonance formation in cylindrical cell without buffer gas irradiated by a narrow laser beam. We take into account non-zero probabilities of elastic ("specular") and inelastic ("sticking") collision between the atom and the cell wall. We have developed a theoretical model based on averaging over the random Ramsey pulse sequences of times that atom spent in and out of the beam. It is shown that the shape of coherent population trapping re...

  15. Trapping of ultra cold atoms in a 3He/4He dilution refrigerator

    Jessen, F; Bell, S C; Vergien, P; Hattermann, H; Weiss, P; Rudolph, M; Reinschmidt, M; Meyer, K; Gaber, T; Cano, D; Guenther, A; Bernon, S; Koelle, D; Kleiner, R; Fortagh, J

    2013-01-01

    We describe the preparation of ultra cold atomic clouds in a dilution refrigerator. The closed cycle 3He/4He cryostat was custom made to provide optical access for laser cooling, optical manipulation and detection of atoms. We show that the cryostat meets the requirements for cold atom experiments, specifically in terms of operating a magneto-optical trap, magnetic traps and magnetic transport under ultra high vacuum conditions. The presented system is a step towards the creation of a quantum hybrid system combining ultra cold atoms and solid state quantum devices.

  16. Photoassociative Cooling and Trapping of Center-of-Mass Motion of Atom-Pairs

    Saha, Subrata; Deb, Bimalendu

    2015-01-01

    We show that it is possible to cool and trap the center-of-mass (COM) motion of atom-pairs by a lin$\\perp$lin Sisyphus-like method using counter-propagating photoassociation lasers. This method relies on the photoassociative coupling between an excited molecular bound state and a single-channel continuum of states of scattering between ground-state atoms. We demonstrate that one can generate molecular spin-dependent periodic potentials by this method for trapping the COM motion of pairs of ground-state atoms. We illustrate this with numerical calculations using fermionic $^{171}$Yb atoms as an example.

  17. Entanglement and quantum state transfer between two atoms trapped in two indirectly coupled cavities

    Zheng, Bin; Shen, Li-Tuo; Chen, Ming-Feng

    2016-05-01

    We propose a one-step scheme for implementing entanglement generation and the quantum state transfer between two atomic qubits trapped in two different cavities that are not directly coupled to each other. The process is realized through engineering an effective asymmetric X-Y interaction for the two atoms involved in the gate operation and an auxiliary atom trapped in an intermediate cavity, induced by virtually manipulating the atomic excited states and photons. We study the validity of the scheme as well as the influences of the dissipation by numerical simulation and demonstrate that it is robust against decoherence.

  18. Bose-Einstein atoms in atomic traps with predominantly attractive two-body interactions

    Using the Perron-Frobenius theorem, we prove that the results by Wilkin, Gunn, and Smith [Phys. Rev. Lett. 80, 2265 (1998)] for the ground states at angular momentum L of N harmonically trapped Bose atoms, interacting via weak attractive δ2(r) forces, are valid for a broad class of predominantly attractive interactions V(r), not necessarily attractive for any r. This class is described by sufficient conditions on the two-body matrix elements of the potential V(r). It includes, in particular, the Gaussian attraction of arbitrary radius, -1/r-Coulomb and log(r)-Coulomb forces, as well as all the short-range interactions satisfying inequality ∫d2r-vectorV(r)<0. In the precollapse regime, the angular momentum L is concentrated in the collective 'center-of-mass' mode, and there is no condensation at high L

  19. Trapping atoms in a bottle beam generated by a diffractive optical element

    Ivanov, V.; Isaacs, J.; Saffman, M.; Kemme, S. A.; Brady, G. R.; Ellis, A. R.; Wendt, J. R.

    2012-06-01

    Highly excited Rydberg states have been used to demonstrate a neutral atom quantum gate, two-atom entanglement and hold promise for studies of surface potentials, such as the Casimir-Polder potential. Blue detuned Optical Bottle Beam (BoB) traps where atoms are confined in intensity minima trap both ground and Rydberg state atoms. This minimizes qubit decoherence and allows accurate measurements of the frequencies of the Rydberg transitions. We have generated optical bottle beam traps using a segmented diffractive optical element with π phase shift between the inner and outer regions. The idea for this trap follows the approach used by Ozeri, et al. Phys. Rev. A 59, R1750 (1999) but integrates the phase shift and focusing lens into a single diffractive element fabricated at Sandia National Lab. Measured profiles of the trap light intensity are compared with numerical predictions using a Fresnel diffraction code. Progress towards atom trapping in the bottle for studies of atom-surface interactions will be presented.

  20. Enhanced Raman sideband cooling of caesium atoms in a vapour-loaded magneto-optical trap

    Li, Y; Feng, G; Nute, J; Piano, S; Hackermuller, L; Ma, J; Xiao, L; Jia, S

    2015-01-01

    We report enhanced three-dimensional degenerated Raman sideband cooling (3D DRSC) of caesium (Cs) atoms in a standard single-cell vapour-loading magneto-optical trap. Our improved scheme involves using a separate repumping laser and optimized lattice detuning. We load $1.5 \\times 10^7$ atoms into the Raman lattice with a detuning of -15.5 GHz (to the ground F = 3 state). Enhanced 3D DRSC is used to cool them from 60 $\\mu$K to 1.7 $\\mu$K within 12 ms and the number of obtained atoms is about $1.2 \\times 10^7$. A theoretical model is proposed to simulate the measured number of trapped atoms. The result shows good agreement with the experimental data. The technique paves the way for loading a large number of ultracold Cs atoms into a crossed dipole trap and efficient evaporative cooling in a single-cell system.

  1. Multiscale quantum-defect theory for two interacting atoms in a symmetric harmonic trap

    Chen, Yujun; Gao, Bo

    2007-01-01

    We present a multiscale quantum-defect theory (QDT) for two identical atoms in a symmetric harmonic trap that combines the quantum-defect theory for the van der Waals interaction [B. Gao, Phys. Rev. A \\textbf{64}, 010701(R) (2001)] at short distances with a quantum-defect theory for the harmonic trapping potential at large distances. The theory provides a systematic understanding of two atoms in a trap, from deeply bound molecular states and states of different partial waves, to highly excite...

  2. Trapping of Neutral Mercury Atoms and Prospects for Optical Lattice Clocks

    Hachisu, H.; Miyagishi, K.; Porsev, S. G.; Derevianko, A.; Ovsiannikov, V. D.; Pal'chikov, V. G.; Takamoto, M.; Katori, H.

    2007-01-01

    We report a vapor-cell magneto-optical trapping of Hg isotopes on the ${}^1S_0-{}^3P_1$ intercombination transition. Six abundant isotopes, including four bosons and two fermions, were trapped. Hg is the heaviest non-radioactive atom trapped so far, which enables sensitive atomic searches for ``new physics'' beyond the standard model. We propose an accurate optical lattice clock based on Hg and evaluate its systematic accuracy to be better than $10^{-18}$. Highly accurate and stable Hg-based ...

  3. Trapping of neutral mercury atoms and prospects for optical lattice clocks.

    Hachisu, H; Miyagishi, K; Porsev, S G; Derevianko, A; Ovsiannikov, V D; Pal'chikov, V G; Takamoto, M; Katori, H

    2008-02-01

    We report vapor-cell magneto-optical trapping of Hg isotopes on the (1)S(0)-(3)P(1) intercombination transition. Six abundant isotopes, including four bosons and two fermions, were trapped. Hg is the heaviest nonradioactive atom trapped so far, which enables sensitive atomic searches for "new physics" beyond the standard model. We propose an accurate optical lattice clock based on Hg and evaluate its systematic accuracy to be better than 10;{-18}. Highly accurate and stable Hg-based clocks will provide a new avenue for the research of optical lattice clocks and the time variation of the fine-structure constant. PMID:18352368

  4. Trapping of Neutral Mercury Atoms and Prospects for Optical Lattice Clocks

    Hachisu, H; Porsev, S G; Derevianko, A; Ovsiannikov, V D; Pal'chikov, V G; Takamoto, M; Katori, H

    2007-01-01

    We report a vapor-cell magneto-optical trapping of Hg isotopes on the ${}^1S_0-{}^3P_1$ intercombination transition. Six abundant isotopes, including four bosons and two fermions, were trapped. Hg is the heaviest non-radioactive atom trapped so far, which enables sensitive atomic searches for ``new physics'' beyond the standard model. We propose an accurate optical lattice clock based on Hg and evaluate its systematic accuracy to be better than $10^{-18}$. Highly accurate and stable Hg-based clocks will provide a new avenue for the research of optical lattice clocks and the time variation of the fine-structure constant.

  5. Simultaneous Magneto-Optical Trapping of Fermionic 40K and Bosonic 87Rb Atoms

    WEI Dong; XIONG De-Zhi; CHEN Hai-Xia; WANG Peng-Jun; GUO Lu; ZHANG Jing

    2007-01-01

    We report on simultaneous magneto-optical trapping of fermionic 40K and bosonic 87Rb atoms. This trap is the first step towards quantum degenerate fermi gas 40K. Laser lights for the two-species magneto-optical trap (MOT) are generated from diode lasers and tapered amplifier. The enriched 40K dispenser is utilized in the experimental setup. We obtain up to 107 ~108 40K and 108 ~109 87Rb atoms respectively in the steady-state single-species MOT.

  6. The influence of optical molasses in loading a shallow optical trap

    Hamilton, Mathew S; Roberts, Jacob L

    2008-01-01

    We have examined loading of 85Rb atoms into a shallow Far-Off-Resonance Trap (FORT) from an optical molasses and compared it to loading from a Magneto-Optical Trap (MOT). We found that substantially more atoms could be loaded into the FORT via an optical molasses as compared to loading from the MOT alone. To determine why this was the case, we measured the rate of atoms loaded into the FORT and the losses from the FORT during the loading process. For both MOT and molasses loading, we examined atom load rate and losses over a range of detunings as well as hyperfine pump powers. We found that the losses induced during MOT loading were essentially the same as the losses induced during molasses loading at the same MOT/molasses detuning. In contrast, load rate of the molasses was higher than that of a MOT at a given detuning. This caused the optical molasses to be able to load more atoms than the MOT. Optimization of FORT loading form an optical molasses improved the number of atoms we could trap by a factor of tw...

  7. Lattices of ultracold atom traps over arrays of nano- and mesoscopic superconducting disks

    Sokolovsky, Vladimir; Prigozhin, Leonid

    2016-04-01

    A lattice of traps for ultracold neutral atoms is a promising tool for experimental investigation in quantum physics and quantum information processing. We consider regular arrays of thin film type-II superconducting nanodisks, with only one pinned vortex in each of them, and also arrays of mesoscopic disks, each containing many vortices whose distribution is characterized by the superconducting current density. In both cases we show theoretically that the induced magnetic field can create a 3D lattice of magnetic traps for cold atoms without any additional bias field. Applying a bias DC field parallel to the superconductor surface, one can control the depth and sizes of the traps, their heights above the chip surface, potential barriers between the traps, as well as the structure and dimension of the lattices. In the adiabatic approximation the atom cloud shape is represented by the shape of a closed iso-surface of the magnetic field magnitude chosen in accordance with the atom cloud temperature. The computed trap sizes, heights and the distances between the neighboring traps are typically from tens to hundreds nanometers for nanodisks and of the order of 1 μm for mesoscopic disks. Our calculations show that the depth of magnetic traps on mesoscopic disks is, typically, between 0.3 G and 7.6 G; for the nanodisks the depth is about 0.3 G.

  8. Coherence preservation of a single neutral atom qubit transferred between magic-intensity optical traps

    Yang, Jiaheng; Guo, Ruijun; Xu, Peng; Wang, Kunpeng; Sheng, Cheng; Liu, Min; Wang, Jin; Derevianko, Andrei; Zhan, Mingsheng

    2016-01-01

    We demonstrate that the coherence of a single mobile atomic qubit can be well preserved during a transfer process among different optical dipole traps (ODTs). This is a prerequisite step in realizing a large-scale neutral atom quantum information processing platform. A qubit encoded in the hyperfine manifold of $^{87}$Rb atom is dynamically extracted from the static quantum register by an auxiliary moving ODT and reinserted into the static ODT. Previous experiments were limited by decoherences induced by the differential light shifts of qubit states. Here we apply a magic-intensity trapping technique which mitigates the detrimental effects of light shifts and substantially enhances the coherence time to $225 \\pm 21\\,\\mathrm{ms}$. The experimentally demonstrated magic trapping technique relies on the previously neglected hyperpolarizability contribution to the light shifts, which makes the light shift dependence on the trapping laser intensity to be parabolic. Because of the parabolic dependence, at a certain ...

  9. Possibility of triple magic trapping of clock and Rydberg states of divalent atoms in optical lattices

    Topcu, T

    2016-01-01

    We predict the possibility of "triply-magic" optical lattice trapping of neutral divalent atoms. In such a lattice, the ${^1}\\!S_{0}$ and ${^3}\\!P_{0}$ clock states and an additional Rydberg state experience identical optical potentials, fully mitigating detrimental effects of the motional decoherence. In particular, we show that this triply magic trapping condition can be satisfied for Yb atom at optical wavelengths and for various other divalent systems (Ca, Mg, Hg and Sr) in the UV region. We assess the quality of triple magic trapping conditions by estimating the probability of excitation out of the motional ground state as a result of the excitations between the clock and the Rydberg states. We also calculate trapping laser-induced photoionization rates of divalent Rydberg atoms at magic frequencies. We find that such rates are below the radiative spontaneous-emission rates, due to the presence of Cooper minima in photoionization cross-sections.

  10. New cryogenic trap design for speciation analysis of arsenic by hydride generation-atomic absorption spectrometry

    Svoboda, Milan; Kratzer, Jan; Dědina, Jiří

    Praha, 2014. s. 240-240. ISBN 978-80-905704-1-2. [European Symposium on Atomic Spectrometry ESAS 2014 & Czech-Slovak Spectroscopic Conference /15./. 16.03.2014-21.03.2014, Praha] R&D Projects: GA AV ČR(CZ) M200311202 Institutional support: RVO:68081715 Keywords : atomic absorption spectrometry * hydride generation * cryogenic trapping Subject RIV: CB - Analytical Chemistry, Separation

  11. Generation of Three-Dimensional Entangled States for Two Atoms Trapped in Different Cavities

    ZHENG Shi-Biao

    2005-01-01

    @@ We propose a scheme for generating three-dimensional entangled states for two atoms trapped in two separate cavities. The scheme is based on the detection of photons leaking from the cavities after the atom-cavity interaction.The scheme is useful for the test of quantum nonlocality and quantum information processing.

  12. Velocity tuning of friction with two trapped atoms

    Gangloff, Dorian; Counts, Ian; Jhe, Wonho; Vuletić, Vladan

    2015-01-01

    Friction is the basic, ubiquitous mechanical interaction between two surfaces that results in resistance to motion and energy dissipation. In spite of its technological and economic significance, our ability to control friction remains modest, and our understanding of the microscopic processes incomplete. At the atomic scale, mismatch between the two contacting crystal lattices can lead to a reduction of stick-slip friction (structural lubricity), while thermally activated atomic motion can give rise to a complex velocity dependence, and nearly vanishing friction at sufficiently low velocities (thermal lubricity). Atomic force microscopy has provided a wealth of experimental results, but limitations in the dynamic range, time resolution, and control at the single-atom level have hampered a full quantitative description from first principles. Here, using an ion-crystal friction emulator with single-atom, single substrate-site spatial resolution and single-slip temporal resolution, we measure the friction force...

  13. Exact spatial density of ideal Bose atoms in a one-dimensional harmonic trap

    Cheng, Ze

    2016-05-01

    We have proposed an exact analytical solution to the problem of Bose–Einstein condensation (BEC) of harmonically trapped, one-dimensional, and ideal atoms. It is found that the number of atoms in vapor is characterized by an analytical function, which involves a q -digamma function in mathematics. We employ the q -digamma function to calculate the spatial density n(z;T, N) of ideal Bose atoms in a one-dimensional harmonic trap. The first main finding in this paper is that when Bose atoms are in the normal state, the density profile exhibits Friedel oscillations. The second main finding is that when Bose atoms are in the BEC state, the density profile exhibits a sharp peak with extremely narrow width. The third main finding is that the central peak of the spatial density is a monotonically increasing function of the number of atoms N but is a monotonically decreasing function of temperature T.

  14. Laser cooling of rubidium atoms in a magneto-optical trap

    Hopkins, Stephen Anthony

    1996-01-01

    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 pl...

  15. Design and fabrication of diffractive atom chips for laser cooling and trapping

    Cotter, J P; Griffin, P F; Rabey, I M; Docherty, K; Riis, E; Arnold, A S; Hinds, E A

    2016-01-01

    It has recently been shown that optical reflection gratings fabricated directly into an atom chip provide a simple and effective way to trap and cool substantial clouds of atoms [1,2]. In this article we describe how the gratings are designed and micro-fabricated and we characterise their optical properties, which determine their effectiveness as a cold atom source. We use simple scalar diffraction theory to understand how the morphology of the gratings determines the power in the diffracted beams.

  16. Ultraviolet light-induced atom desorption for large rubidium and potassium magneto-optical traps

    We show that light-induced atom desorption (LIAD) can be used as a flexible atomic source for large 87Rb and 40K magneto-optical traps. The use of LIAD at short wavelengths allows for fast switching of the desired vapor pressure and permits experiments with long trapping and coherence times. The wavelength dependence of the LIAD effect for both species was explored in a range from 630 to 253 nm in an uncoated quartz cell and a stainless steel chamber. Only a few mW/cm2 of near-UV light produce partial pressures that are high enough to saturate a magneto-optical trap at 3.5x10987Rb atoms or 7x10740K atoms. Loading rates as high as 1.2x10987Rb atoms/s and 8x10740K atoms/s were achieved without the use of a secondary atom source. After the desorption light is turned off, the pressure quickly decays back to equilibrium with a time constant as short as 200 μs, allowing for long trapping lifetimes after the MOT loading phase

  17. Trapping and cooling of rf-dressed atoms in a quadrupole magnetic field

    Morizot, Olivier; Pottie, Paul-Eric; Lorent, Vincent; Perrin, Hélène

    2007-01-01

    We observe the spontaneous evaporation of atoms confined in a bubble-like rf-dressed trap (Zobay and Garraway, 2001). The atoms are confined in a quadrupole magnetic trap and are dressed by a linearly polarized rf field. The evaporation is related to the presence of holes in the trap, at the positions where the rf coupling vanishes, due to its vectorial character. The final temperature results from a competition between residual heating and evaporation efficiency, which is controlled via the height of the holes with respect to the bottom of the trap. The experimental data are modeled by a Monte-Carlo simulation predicting a small increase in phase space density limited by the heating rate. This increase was within the phase space density determination uncertainty of the experiment.

  18. Action Spectroscopy of Molecular Ions and Studies of Cold Collsions in a Hybrid Atom-Ion Trap

    Schowalter, Steven

    2016-01-01

    This Dissertation details the development of state-of-the-art hybrid atom-ion trapping architecture and technique towards increasing the quantum control of matter and the detection of chemical processes at cold temperatures. Experimental work discussed herein is performed primarily using the second-generation of the MOTion trap, a hybrid atom-ion trap consisting of a co-located magneto-optical trap (MOT) and a linear quadrupole trap (LQT), with which $^{40}$Ca and a variety of atomic and mol...

  19. Tunneling theory for tunable open quantum systems of ultracold atoms in one-dimensional traps

    Lundmark, Rikard; Forssén, Christian; Rotureau, Jimmy

    2015-01-01

    The creation of tunable open quantum systems is becoming feasible in current experiments with ultracold atoms in low-dimensional traps. In particular, the high degree of experimental control over these systems allows detailed studies of tunneling dynamics, e.g., as a function of the trapping geometry and the interparticle interaction strength. In order to address this exciting opportunity we present a theoretical framework for two-body tunneling based on the rigged Hilbert space formulation. ...

  20. Influence of trapping potentials on the phase diagram of bosonic atoms in optical lattices

    Giampaolo, S. M.; Illuminati, F.; Mazzarella, G.; De Siena, S.

    2004-01-01

    We study the effect of external trapping potentials on the phase diagram of bosonic atoms in optical lattices. We introduce a generalized Bose-Hubbard Hamiltonian that includes the structure of the energy levels of the trapping potential, and show that these levels are in general populated both at finite and zero temperature. We characterize the properties of the superfluid transition for this situation and compare them with those of the standard Bose-Hubbard description. We briefly discuss s...

  1. Determination of tellurium by hydride generation with in situ trapping flame atomic absorption spectrometry

    Matusiewicz, H.; Krawczyk, M. [Politechn Poznanska, Poznan (Poland)

    2007-03-15

    The analytical performance of coupled hydride generation - integrated atom trap (HG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system was evaluated for determination of Te in reference material (GBW 07302 Stream Sediment), coal fly ash and garlic. Tellurium, using formation of H{sub 2}Te vapors, is atomized in air-acetylene flame-heated IAT. A new design HG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangernents (a water-cooled single silica tube, double-slotted quartz tube or an 'integrated trap') was investigated. An improvement in detection limit was achieved compared with using either of the above atom trapping techniques separately. The concentration detection limit, defined as 3 times the blank standard deviation (3{sigma}), was 0.9 ng mL{sup -1} for Te. For a 2 min in situ preconcentration time (sample volume of 2 mL), sensitivity enhancement compared to flame AAS, was 222 fold, using the hydride generation atom trapping technique. The sensitivity can be further improved by increasing the collection time. The precision, expressed as RSD, was 7.0% (n = 6) for Te. The accuracy of the method was verified using a certified reference material (GBW 07302 Stream Sediment) by aqueous standard calibration curves. The measured Te contents of the reference material was in agreement with the information value. The method was successfully applied to the determination of tellurium in coal fly ash and garlic.

  2. Quantum coherent tractor beam effect for atoms trapped near a nanowaveguide

    Sadgrove, Mark; Wimberger, Sandro; Nic Chormaic, Síle

    2016-01-01

    We propose several schemes to realize a tractor beam effect for ultracold atoms in the vicinity of a few-mode nanowaveguide. Atoms trapped near the waveguide are transported in a direction opposite to the guided mode propagation direction. We analyse three specific examples for ultracold 23Na atoms trapped near a specific nanowaveguide (i.e. an optical nanofibre): (i) a conveyor belt-type tractor beam effect, (ii) an accelerator tractor beam effect, and (iii) a quantum coherent tractor beam effect, all of which can effectively pull atoms along the nanofibre toward the light source. This technique provides a new tool for controlling the motion of particles near nanowaveguides with potential applications in the study of particle transport and binding as well as atom interferometry. PMID:27440516

  3. Quantum coherent tractor beam effect for atoms trapped near a nanowaveguide

    Sadgrove, Mark; Wimberger, Sandro; Nic Chormaic, Síle

    2016-07-01

    We propose several schemes to realize a tractor beam effect for ultracold atoms in the vicinity of a few-mode nanowaveguide. Atoms trapped near the waveguide are transported in a direction opposite to the guided mode propagation direction. We analyse three specific examples for ultracold 23Na atoms trapped near a specific nanowaveguide (i.e. an optical nanofibre): (i) a conveyor belt-type tractor beam effect, (ii) an accelerator tractor beam effect, and (iii) a quantum coherent tractor beam effect, all of which can effectively pull atoms along the nanofibre toward the light source. This technique provides a new tool for controlling the motion of particles near nanowaveguides with potential applications in the study of particle transport and binding as well as atom interferometry.

  4. Low-Velocity Intense Source of Atoms from a Magneto-optical Trap

    We have produced and characterized an intense, slow, and highly collimated atomic beam extracted from a standard vapor cell magneto-optical trap (MOT).The technique used is dramatically simpler than previous methods for producing very cold atomic beams. We have created a 0.6mm diameter rubidium atomic beam with a continuous flux of 5x109/s and a pulsed flux 10times greater. Its longitudinal velocity distribution is centered at 14 m/s with a FWHM of 2.7 m/s. Through an efficient recycling process, 70% of the atoms trapped in the MOT are loaded into the atomic beam. copyright 1996 The American Physical Society

  5. Light-induced atomic desorption for loading a sodium magneto-optical trap

    We report studies of photon-stimulated desorption, also known as light-induced atomic desorption, of sodium atoms from a vacuum-cell glass surface used for loading a magneto-optical trap (MOT). Fluorescence detection was used to record the trapped atom number and the desorption rate. We observed a steep wavelength dependence of the desorption process above 2.6 eV photon energy, a result significant for estimations of sodium vapor density in the lunar atmosphere. Our data fit well to a simple model for the loading of the MOT dependent only on the sodium desorption rate and residual gas density. Up to 3.7x107 Na atoms were confined under ultrahigh-vacuum conditions, creating promising loading conditions for a vapor-cell-based atomic Bose-Einstein condensate of sodium.

  6. Bose-Einstein condensation of trapped atoms with dipole interactions

    Nho, Kwangsik; Landau, D. P.

    2005-01-01

    The path integral Monte Carlo method is used to simulate dilute trapped Bose gases and to investigate the equilibrium properties at finite temperatures. The quantum particles have a long-range dipole-dipole interaction and a short-range s-wave interaction. Using an anisotropic pseudopotential for the long-range dipolar interaction and a hard-sphere potential for the short-range s-wave interaction, we calculate the energetics and structural properties as a function of temperature and the numbe...

  7. Noise-induced heating of squeezed states in atom traps

    We present a general model of a quantum parametric oscillator heated by coupled fluctuating fields. Two kinds of external fields are considered: an external fluctuating driving force, and a noise in the basic frequency of the oscillator. The energy increase and the change in the square variances of position and momentum produced in such systems are calculated. As a particular example, we study the case of a Paul trap and the evolution of coherent and squeezed states under general conditions. The analysis is also extended to the evolution of superpositions of coherent states

  8. Noise-induced heating of squeezed states in atom traps

    Hacyan, S; Jauregui, R [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, Mexico DF 01000 (Mexico)

    2003-04-01

    We present a general model of a quantum parametric oscillator heated by coupled fluctuating fields. Two kinds of external fields are considered: an external fluctuating driving force, and a noise in the basic frequency of the oscillator. The energy increase and the change in the square variances of position and momentum produced in such systems are calculated. As a particular example, we study the case of a Paul trap and the evolution of coherent and squeezed states under general conditions. The analysis is also extended to the evolution of superpositions of coherent states.

  9. A model of optical trapping cold atoms using a metallic nano wire with surface plasmon effect

    Thi Phuong Lan, Nguyen; Thi Nga, Do; Viet, Nguyen Ai

    2016-06-01

    In this work, we construct a new model of optical trapping cold atoms with a metallic nano wire by using surface plasmon effect generated by strong field of laser beams. Using the skin effect, we send a strong oscillated electromagnetic filed through the surface of a metallic nano wire. The local field generated by evanescent effect creates an effective attractive potential near the surface of metallic nano wires. The consideration of some possible boundary and frequency conditions might lead to non-trivial bound state solution for a cold atom. We discus also the case of the laser reflection optical trap with shell-core design, and compare our model with another recent schemes of cold atom optical traps using optical fibers and carbon nanotubes.

  10. Quantum information entropies of ultracold atomic gases in a harmonic trap

    Tutul Biswas; Tarun Kanti Ghosh

    2011-10-01

    The position and momentum space information entropies of weakly interacting trapped atomic Bose–Einstein condensates and spin-polarized trapped atomic Fermi gases at absolute zero temperature are evaluated. We find that sum of the position and momentum space information entropies of these quantum systems containing atoms confined in a $D(≤ 3)$-dimensional harmonic trap has a universal form as $S^{(D)}_t = N(a D − b ln N)$, where ∼ 2.332 and = 2 for interacting bosonic systems and a ∼ 1.982 and = 1 for ideal fermionic systems. These results obey the entropic uncertainty relation given by Beckner, Bialynicki-Birula and Myceilski.

  11. Fluorescence spectra of atomic ensembles in a magneto-optical trap as an optical lattice

    Yoon, Seokchan; Kang, Sungsam; Kim, Wook-Rae; Kim, Jung-Ryul; An, Kyungwon

    2015-01-01

    We present a study on characteristics of a magneto-optical trap (MOT) as an optical lattice. Fluorescence spectra of atoms trapped in a MOT with a passively phase-stabilized beam configuration have been measured by means of the photon-counting heterodyne spectroscopy. We observe a narrow Rayleigh peak and well-resolved Raman sidebands in the fluorescence spectra which clearly show that the MOT itself behaves as a three-dimensional optical lattice. Optical-lattice-like properties of the phase-stabilized MOT such as vibrational frequencies and lineshapes of Rayleigh peak and Raman sidebands are investigated systematically for various trap conditions.

  12. Antiferromagnetic Heisenberg Spin Chain of a Few Cold Atoms in a One-Dimensional Trap

    Murmann, S.; Deuretzbacher, F.; Zürn, G.; Bjerlin, J.; Reimann, S. M.; Santos, L.; Lompe, T.; Jochim, S.

    2015-11-01

    We report on the deterministic preparation of antiferromagnetic Heisenberg spin chains consisting of up to four fermionic atoms in a one-dimensional trap. These chains are stabilized by strong repulsive interactions between the two spin components without the need for an external periodic potential. We independently characterize the spin configuration of the chains by measuring the spin orientation of the outermost particle in the trap and by projecting the spatial wave function of one spin component on single-particle trap levels. Our results are in good agreement with a spin-chain model for fermionized particles and with numerically exact diagonalizations of the full few-fermion system.

  13. Measurement of the trapping lifetime close to a cold metallic surface on a cryogenic atom-chip

    Emmert, Andreas; Nogues, Gilles; Brune, Michel; Raimond, Jean-Michel; Haroche, Serge

    2009-01-01

    We have measured the trapping lifetime of magnetically trapped atoms in a cryogenic atom-chip experiment. An ultracold atomic cloud is kept at a fixed distance from a thin gold layer deposited on top of a superconducting trapping wire. The lifetime is studied as a function of the distances to the surface and to the wire. Different regimes are observed, where loss rate is determined either by the technical current noise in the wire or the Johnson-Nyquist noise in the metallic gold layer, in good agreement with theoretical predictions. Far from the surface, we observe exceptionally long trapping times for an atom-chip, in the 10-minutes range.

  14. Mathematical Modeling of Ultracold Few-Body Processes in Atomic Traps

    Melezhik V.S.

    2016-01-01

    Full Text Available We discuss computational aspects of the developed mathematical models for ultracold few-body processes in atomic traps. The key element of the elaborated computational schemes is a nondirect product discrete variable representation (npDVR we have suggested and applied to the time-dependent and stationary Schrödinger equations with a few spatial variables. It turned out that this approach is very effcient in quantitative analysis of low-dimensional ultracold few-body systems arising in confined geometry of atomic traps. The effciency of the method is demonstrated here on two examples. A brief review is also given of novel results obtained recently.

  15. Investigation of ultracold atoms and molecules in a dark magneto-optical trap

    Wang Li-Rong; Ji Zhong-Hua; Yuan Jin-Peng; Yang Yan; Zhao Yan-Ting; Ma Jie; Xiao Lian-Tuan; Jia Suo-Tang

    2012-01-01

    In this paper,ultracold atoms and molecules in a dark magneto-optical trap (MOT) are studied via depumping the cesium cold atoms into the dark hyperfine ground state.The collision rate is reduced to 0.45 s-1 and the density of the atoms is increased to 5.6 × 1011 cm-3 when the fractional population of the atoms in the bright hyperfine ground state is as low as 0.15.The vibrational spectra of the ultracold cesium molecules are also studied in a standard MOT and in a dark MOT separately.The experimental results are analyzed by using the perturbative quantum approach.

  16. Observation of Entanglement of a Single Photon with a Trapped Atom

    We report the observation of entanglement between a single trapped atom and a single photon at a wavelength suitable for low-loss communication over large distances, thereby achieving a crucial step towards long range quantum networks. To verify the entanglement, we introduce a single atom state analysis. This technique is used for full state tomography of the atom-photon qubit pair. The detection efficiency and the entanglement fidelity are high enough to allow in a next step the generation of entangled atoms at large distances, ready for a final loophole-free Bell experiment

  17. An apparatus for immersing trapped ions into an ultracold gas of neutral atoms.

    Schmid, Stefan; Härter, Arne; Frisch, Albert; Hoinka, Sascha; Denschlag, Johannes Hecker

    2012-05-01

    We describe a hybrid vacuum system in which a single ion or a well-defined small number of trapped ions (in our case Ba(+) or Rb(+)) can be immersed into a cloud of ultracold neutral atoms (in our case Rb). This apparatus allows for the study of collisions and interactions between atoms and ions in the ultracold regime. Our setup is a combination of a Bose-Einstein condensation apparatus and a linear Paul trap. The main design feature of the apparatus is to first separate the production locations for the ion and the ultracold atoms and then to bring the two species together. This scheme has advantages in terms of stability and available access to the region where the atom-ion collision experiments are carried out. The ion and the atoms are brought together using a moving one-dimensional optical lattice transport which vertically lifts the atomic sample over a distance of 30 cm from its production chamber into the center of the Paul trap in another chamber. We present techniques to detect and control the relative position between the ion and the atom cloud. PMID:22667603

  18. Entangled Radiation through an Atomic Reservoir Controlled by Coherent Population Trapping

    We show that it is possible to generate Einstein–Podolsky–Rosen (EPR) entangled radiation using an atomic reservoir controlled by coherent population trapping. A beam of three-level atoms is initially prepared in near-coherent population trapping (CPT) state and acts as a long-lived coherence-controlled reservoir. Four-wave mixing leads to amplification of cavity modes resonant with Rabi sidebands of the atomic dipole transitions. The cavity modes evolve into an EPR state, whose degree of entanglement is controlled by the intensities and the frequencies of the driving fields. This scheme uses the long-lived CPT coherence and is robust against spontaneous emission of the atomic beam. At the same time, this scheme is implemented in a one-step procedure, not in a two-step procedure as was required in Phys. Rev. Lett. 98 (2007) 240401. (fundamental areas of phenomenology (including applications))

  19. Trap losses induced by near-resonant Rydberg dressing of cold atomic gases

    Aman, J. A.; DeSalvo, B. J.; Dunning, F. B.; Killian, T. C.; Yoshida, S.; Burgdörfer, J.

    2016-04-01

    The near-resonant dressing of cold strontium gases and Bose-Einstein condensates contained in an optical dipole trap (ODT) with the 5 s 30 s S31 Rydberg state is investigated as a function of the effective two-photon Rabi frequency, detuning, and dressing time. The measurements demonstrate that a rapid decrease in the ground-state atom population in the ODT occurs even for weak dressing and when well detuned from resonance. This decrease is attributed to Rydberg atom excitation, which can lead to direct escape from the trap and to population of very long-lived 5 s 5 p 0, 2 3P metastable states. The effects of interactions between Rydberg atoms, including those populated by blackbody radiation, are analyzed. The work has important implications when considering the use of Rydberg dressing to control the interactions between dressed ground-state atoms.

  20. Search for Electric dipole moment (EDM) in laser cooled and trapped 225Ra atoms

    Kalita, Mukut; Bailey, Kevin; Dietrich, Matthew; Green, John; Holt, Roy; Korsch, Wolfgang; Lu, Zheng-Tian; Lemke, Nathan; Mueller, Peter; O'Connor, Tom; Parker, Richard; Singh, Jaideep; Trimble, Will; Argonne National Laboratory Collaboration; University Of Chicago Collabration; University Of Kentucky Collaboration

    2014-05-01

    We are searching for an EDM of the diamagnetic 225Ra atom. 225Ra has nuclear spin I =1/2. Experimental sensitivity to its EDM is enhanced due to its heavy mass and the increased Schiff moment of its octupole deformed nucleus. Our experiment involves collecting laser cooled Ra atoms in a magneto-optical trap (MOT), transporting them 1 meter with a far off-resonant optical dipole trap (ODT) and then transferring the atoms to a second standing-wave ODT in our experimental chamber. We will report our recent experiences in polarizing and observing Larmor precession of 225Ra atoms in parallel electric and magnetic fields in a magnetically shielded region and progress towards a first measurement of the EDM of 225Ra. This work is supported by DOE, Office of Nuclear Physics, under contract No. DE-AC02-06CH11357 and contract No. DE-FG02-99ER41101.

  1. Enhancement in the number of trapped atoms in a cesium magneto-optical trap by a near-resonant control laser

    We demonstrate enhancement in the number of trapped cesium atoms in a magneto-optical trap (MOT) using a control laser that illuminates only a small faction of the capture region of the trap without interacting with the cold cloud of atoms. The enhancement is maximized when the laser is slightly blue detuned with respect to the cooling transition. Trap loading curves point to approximately a twofold increase in the capture rate, which as a consequence results in the increase in the steady state number of trapped atoms. Enhanced loading is confirmed by MOT loading and decay curves taken under the modulation of the control laser beam. Optical pumping of the inaccessible Zeeman states into the stretched states is suggested as a possible mechanism

  2. Direct Observation of Coherent Population Trapping in a Superconducting Artificial Atom

    Kelly, William R.; Dutton, Zachary; Schlafer, John; Mookerji, Bhaskar; Ohki, Thomas A.; Kline, Jeffrey S.; Pappas, David P.

    2009-01-01

    The phenomenon of Coherent Population Trapping (CPT) of an atom (or solid state "artificial atom"), and the associated effect of Electromagnetically Induced Transparency (EIT), are clear demonstrations of quantum interference due to coherence in multi-level quantum systems. We report observation of CPT in a superconducting phase qubit by simultaneously driving two coherent transitions in a $\\Lambda$-type configuration, utilizing the three lowest lying levels of a local minimum of a phase qubi...

  3. Non-Ground-State Bose-Einstein Condensates of Trapped Atoms

    V. I. Yukalov; Yukalova, E. P.; V. S. Bagnato

    1997-01-01

    The possibility of creating a Bose condensate of trapped atoms in a non-ground state is suggested. Such a nonequilibrium Bose condensate can be formed if one, first, obtains the conventional Bose condensate in the ground state and then transfers the condensed atoms to a non-ground state by means of a resonance pumping. The properties of ground and non-ground states are compared and plausible applications of such nonequilibrium condensates are discussed.

  4. Laser cooling of single trapped atoms to the ground state: a dark state in position space

    Morigi, Giovanna; Cirac Sasturáin, Juan Ignacio,; Ellinger, K; Zoller, P.

    1997-01-01

    We propose a scheme that allows us to laser cool trapped atoms to the ground state of a one-dimensional confining potential. The scheme is based on the creation of a dark state by designing the laser profile, so that the hottest atoms are coherently pumped to another internal level, and then repumped back. The scheme works beyond the Lamb-Dicke limit. We present results of a full quantum treatment for a one-dimensional model.

  5. Three-body loss of trapped ultracold $^{87}$Rb atoms due to a Feshbach resonance

    Yurovsky, V A

    2002-01-01

    The loss of ultracold trapped atoms in the vicinity of a Feshbach resonance is treated as a two-stage reaction, using the Breit-Wigner theory. The first stage is the formation of a resonant diatomic molecule, and the second one is its deactivation by inelastic collisions with other atoms. This model is applied to the analysis of recent experiments on $^{87}$Rb, leading to an estimated value of $6\\times 10^{-11}$ cm$^{3}/$s for the deactivation rate coefficient.

  6. Atomic scale imaging and spectroscopy of individual electron trap states using force detected dynamic tunnelling

    We report the first atomic scale imaging and spectroscopic measurements of electron trap states in completely non-conducting surfaces by dynamic tunnelling force microscopy/spectroscopy. Single electrons are dynamically shuttled to/from individual states in thick films of hafnium silicate and silicon dioxide. The new method opens up surfaces that are inaccessible to the scanning tunnelling microscope for imaging and spectroscopy on an atomic scale.

  7. Preparation of Bose Einstein condensates in realistc trapping potentials for precision atom interferometry

    Posso Trujillo, Katerine; Rasel, Ernst M.; Gaaloul, Naceur; Quantus Team

    Preparation of Bose Einstein condensates in realistc trapping potentials for precision atom interferometry Theoretical studies of the ground state and the dynamical properties of Bose Einstein condensates (BECs) are typically realized by considering the ensemble as being initiaally trapped by a harmonic potential. Dramatic discrepancies were found by comparing numerical results of the long-time expansion of BECs after being released from the harmonic trap, and measurements of the free evolution and delta-kick cooling (DKC) of a 87Rb BEC on large timescales of up to 2 s in micro-gravity (micro-g) environment such as those performed in the QUANTUS project from our group. The modification in the dynamics of a 87Rb BEC with the application of DKC by using experimentally implemented trapping geometries and the effect of gravity have been studied. Three different configurations have been considered: atom chip-based potential, dipole trap and the time-averaged orbiting potential. Such discrepancies may be crucial in high precision atom interferometry experiments in micro-g and zero-g platforms in which the implementation of DKC is mandatory to achieve the long-expansion times required

  8. An apparatus for immersing trapped ions into an ultracold gas of neutral atoms

    Schmid, Stefan; Frisch, Albert; Hoinka, Sascha; Denschlag, Johannes Hecker

    2012-01-01

    We describe a hybrid vacuum system in which a single ion or a well defined small number of trapped ions (in our case Ba$^+$ or Rb$^+$) can be immersed into a cloud of ultracold neutral atoms (in our case Rb). This novel apparatus allows for the study of collisions and interactions between atoms and ions in the ultracold regime. Our setup is a combination of a Bose-Einstein condensation (BEC) apparatus and a linear Paul trap. The main design feature of the apparatus is to first separate the production locations for the ion and the ultracold atoms and then to bring the two species together. This scheme has advantages in terms of stability and available access to the region where the atom-ion collision experiments are carried out. The ion and the atoms are brought together using a novel moving 1-dimensional optical lattice transport which vertically lifts the atomic sample over a distance of 30$\\,$cm from its production chamber into the center of the Paul trap in another chamber. We present techniques to detect ...

  9. Optimizing the production of metastable calcium atoms in a magneto-optical trap

    Gruenert, J; Gruenert, Jan; Hemmerich, Andreas

    2001-01-01

    We investigate the production of long lived metastable (3P2, n=4) calcium atoms in a magneto-optical trap operating on the 1S0 to 1P1 transition at 423 nm. For excited 1P1-atoms a weak decay channel into the triplet states 3P2 and 3P1 exists via the singlet 1D2 (n=3) state. The undesired 3P1-atoms decay back to the ground state within 0.4 ms and can be fully recaptured if the illuminated trap volume is sufficiently large. We obtain a flux of above 10^10 atoms/s into the 3P2-state. We find that our MOT life time of 23 ms is mainly limited by this loss channel and thus the 3P2-production is not hampered by inelasic collisions. If we close the loss channel by repumping the 1D2-atoms with a 671 nm laser back into the MOT cycling transition, a non-exponential 72 ms trap decay is observed indicating the presence of inelastic two-body collisions between 1S0 and 1P1 atoms.

  10. Coherence of a qubit stored in Zeeman levels of a single optically trapped atom

    Rosenfeld, Wenjamin; Weinfurter, Harald [Fakultaet fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, D-80799 Muenchen (Germany); Max-Planck-Institut fuer Quantenoptik, D-85748 Garching (Germany); Volz, Juergen; Weber, Markus [Fakultaet fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, D-80799 Muenchen (Germany)

    2011-08-15

    We experimentally investigate the coherence properties of a qubit stored in the Zeeman substates of the 5{sup 2}S{sub 1/2}, F=1 hyperfine ground level of a single optically trapped {sup 87}Rb atom. Larmor precession of a single atomic spin-1 system is observed by preparing the atom in a defined initial spin state and then measuring the resulting state after a programmable period of free evolution. Additionally, by performing quantum-state tomography, maximum knowledge about the spin coherence is gathered. By using an active magnetic field stabilization and without application of a magnetic guiding field, we achieve transverse and longitudinal dephasing times of T{sub 2}{sup *}=75-150 {mu}s and T{sub 1}>0.5 ms, respectively. We derive the light-shift distribution of a single atom in the approximately harmonic potential of a dipole trap and show that the measured atomic spin coherence is limited mainly by residual position- and state-dependent effects in the optical trapping potential. The improved understanding enables longer coherence times, an important prerequisite for future applications in long-distance quantum communication and computation with atoms in optical lattices, or for a loophole-free test of Bell's inequality.

  11. Magneto-Optical Trapping of 88Sr atoms with 689 nm Laser

    We report the experimental realization of strontium magneto-optical trap (MOT) operating on the intercombination transition 1S0−3P1 at 689 nm, namely red MOT. A 689 nm laser used for cooling and trapping is injection locked to a master laser, whose linewidth is narrowed to 150 Hz by locking to a high finesse optical reference cavity. 88Sr atoms pre-cooled and trapped by the broad 1S0−1P1 transition at 461 nm are transferred to the red MOT with the help of a time sequence controller. The transfer ratio is about 20% and the red MOT's temperature is estimated to be less than 20 μK by the time-of-flight (TOF) image analysis. (atomic and molecular physics)

  12. Production of antihydrogen at reduced magnetic field for anti-atom trapping

    Andresen, G B; Boston, A; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Chartier, M; Deutsch, A; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Gomberoff, K; Hangst, J S; Hayano, R S; Hydomako, R; Jenkins, M J; Jørgensen, L V; Kurchaninov, L; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Page, R D; Povilus, A; Robicheaux, F; Sarid, E; Silveira, D M; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2008-01-01

    We have demonstrated production of antihydrogen in a 1$,$T solenoidal magnetic field. This field strength is significantly smaller than that used in the first generation experiments ATHENA (3$,$T) and ATRAP (5$,$T). The motivation for using a smaller magnetic field is to facilitate trapping of antihydrogen atoms in a neutral atom trap surrounding the production region. We report the results of measurements with the ALPHA (Antihydrogen Laser PHysics Apparatus) device, which can capture and cool antiprotons at 3$,$T, and then mix the antiprotons with positrons at 1$,$T. We infer antihydrogen production from the time structure of antiproton annihilations during mixing, using mixing with heated positrons as the null experiment, as demonstrated in ATHENA. Implications for antihydrogen trapping are discussed.

  13. Measuring isospin mixing in sup 3 sup 6 Ar using a polarized, neutral atom trap

    Melconian, D; Ball, G; Behr, J A; Bricault, P G; Brown, B A; Dombsky, M; Jackson, K P; Fostner, S; Gorelov, A; Groves, M N; Gu, S; Pearson, M R; Towner, I S; Trinczek, M; Vollrath, I

    2003-01-01

    Magneto-optical traps provide a cold, compact cloud of radioactive atoms and therefore are an ideal source for use in precision nuclear beta decay studies. Optical pumping techniques can add a new dimension to such experiments by efficiently polarizing these samples to 0 sup + decays.

  14. Trapping and cooling of sodium atoms for assembly of dipolar molecules

    Yu, Yichao; Hutzler, Nicholas R.; Liu, Lee R.; Zhang, Jessie T.; Ni, Kang-Kuen

    2016-05-01

    In order to create a diatomic molecule with a large electric dipole moment, it is generally necessary to use atoms with very different electronegativities. In the context of bi-alkali molecules, this means combining a light alkali atom with a heavy one. This is the reason why we use NaCs in our molecule assembler experiment; NaCs has the largest induced dipole moment in few kV/cm lab fields. However, the use of sodium atoms also poses challenges. The higher Doppler temperature and lack of efficient D2 polarization gradient cooling increases the necessary depth of our optical dipole (tweezer) traps. The lack of a convenient magic wavelength for the dipole trap creates a large AC stark shift on the optical transition as well as additional heating mechanisms. The light mass of the sodium, and therefore larger Lamb-Dicke parameter and higher recoil temperature, makes it more difficult to perform efficient Raman sideband cooling on the atom in the trap. I will discuss the techniques we use to overcome these challenges, in particular a method to eliminate the light shifts and associated heating mechanisms in tight optical traps.

  15. Trapping of Weak Signal Pulses by Soliton and Trajectory Control in a Coherent Atomic Gas

    Chen, Zhiming

    2016-01-01

    We propose a method for trapping weak signal pulses by soliton and realizing its trajectory control via electromagnetically induced transparency (EIT). The system we consider is a cold, coherent atomic gas with a tripod or multipod level configuration. We show that, due to the giant enhancement of Kerr nonlinearity contributed by EIT, several weak signal pulses can be effectively trapped by a soliton and cotravel stably with ultraslow propagating velocity. Furthermore, we demonstrate that the trajectories of the soliton and the trapped signal pulses can be manipulated by using a Stern-Gerlach gradient magnetic field. As a result, the soliton and the trapped signal pulses display a Stern-Gerlach deflection and both of them can bypass an obstacle together. The results predicted here may be used to design all-optical switching at very low light level.

  16. Intrinsic electron traps in atomic-layer deposited HfO2 insulators

    Cerbu, F.; Madia, O.; Andreev, D. V.; Fadida, S.; Eizenberg, M.; Breuil, L.; Lisoni, J. G.; Kittl, J. A.; Strand, J.; Shluger, A. L.; Afanas'ev, V. V.; Houssa, M.; Stesmans, A.

    2016-05-01

    Analysis of photodepopulation of electron traps in HfO2 films grown by atomic layer deposition is shown to provide the trap energy distribution across the entire oxide bandgap. The presence is revealed of two kinds of deep electron traps energetically distributed at around Et ≈ 2.0 eV and Et ≈ 3.0 eV below the oxide conduction band. Comparison of the trapped electron energy distributions in HfO2 layers prepared using different precursors or subjected to thermal treatment suggests that these centers are intrinsic in origin. However, the common assumption that these would implicate O vacancies cannot explain the charging behavior of HfO2, suggesting that alternative defect models should be considered.

  17. Velocity selective trapping of atoms in a frequency-modulated standing laser wave: wave function and stochastic trajectory approaches

    The wave function of a moderately cold atom in a stationary near-resonant standing light wave delocalizes very fast due to wave packet splitting. However, frequency modulation of the field may suppress packet splitting for some atoms having specific velocities in a narrow range. These atoms remain localized in a small space for a long time. We show that modulated field can not only trap, but also cool the atoms. We perform a numerical experiment with a large atomic ensebmble having wide initial velocity and energy distribution. During the experiment, most of atoms leave the wave while trapped atoms have narrow energy distribution

  18. Temperature and phase-space density of a cold atom cloud in a quadrupole magnetic trap

    Ram, S. P.; Mishra, S. R.; Tiwari, S. K.; Rawat, H. S. [Raja Ramanna Centre for Advanced Technology, Indore (India)

    2014-08-15

    We present studies on modifications in the temperature, number density and phase-space density when a laser-cooled atom cloud from optical molasses is trapped in a quadrupole magnetic trap. Theoretically, for a given temperature and size of the cloud from the molasses, the phase-space density in the magnetic trap is shown first to increase with increasing magnetic field gradient and then to decrease with it after attaining a maximum value at an optimum value of the magnetic-field gradient. The experimentally-measured variation in the phase-space density in the magnetic trap with changing magnetic field gradient is shown to exhibit a similar trend. However, the experimentally-measured values of the number density and the phase-space density are much lower than the theoretically-predicted values. This is attributed to the experimentally-observed temperature in the magnetic trap being higher than the theoretically-predicted temperature. Nevertheless, these studies can be useful for setting a higher phase-space density in the trap by establishing an optimal value of the field gradient for a quadrupole magnetic trap.

  19. Temperature and phase-space density of a cold atom cloud in a quadrupole magnetic trap

    We present studies on modifications in the temperature, number density and phase-space density when a laser-cooled atom cloud from optical molasses is trapped in a quadrupole magnetic trap. Theoretically, for a given temperature and size of the cloud from the molasses, the phase-space density in the magnetic trap is shown first to increase with increasing magnetic field gradient and then to decrease with it after attaining a maximum value at an optimum value of the magnetic-field gradient. The experimentally-measured variation in the phase-space density in the magnetic trap with changing magnetic field gradient is shown to exhibit a similar trend. However, the experimentally-measured values of the number density and the phase-space density are much lower than the theoretically-predicted values. This is attributed to the experimentally-observed temperature in the magnetic trap being higher than the theoretically-predicted temperature. Nevertheless, these studies can be useful for setting a higher phase-space density in the trap by establishing an optimal value of the field gradient for a quadrupole magnetic trap.

  20. Color-charge separation in trapped SU(3) fermionic atoms

    Cold fermionic atoms with three different hyperfine states with SU(3) symmetry confined in one-dimensional optical lattices show color-charge separation, generalizing the conventional spin-charge separation for interacting SU(2) fermions in one dimension. Through time-dependent density-matrix renormalization-group simulations, we explore the features of this phenomenon for a generalized SU(3) Hubbard Hamiltonian. In our numerical simulations of finite-size systems, we observe different velocities of the charge and color degrees of freedom when a Gaussian wave packet or a charge (color) density response to a local perturbation is evolved. The differences between attractive and repulsive interactions are explored and we note that neither a small anisotropy of the interaction, breaking the SU(3) symmetry, nor the filling impedes the basic observation of these effects.

  1. Azimuthal Sisyphus effect for atoms in a toroidal all-optical trap

    Lembessis, V. E. [Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia); Ellinas, D. [Technical University of Crete, Department of Sciences M PHI Q Research Unit GR-731 00 Chania, Crete (Greece); Babiker, M. [Department of Physics, University of York, Heslington, York YO10 5DD, England (United Kingdom)

    2011-10-15

    It is shown that an optical arrangement in which two identical counterpropagating Laguerre-Gaussian doughnut beams LG(l,0) and LG(-l,0) with orthogonal linear polarizations e {sub x} and e {sub y} can lead to azimuthal polarization gradients and an as yet undiscovered azimuthal Sisyphus effect. It is demonstrated that this effect can be utilized in the creation and control of a persistent current of superfluid atoms circulating in a toroidal trap. Such a physical system has recently been highlighted as the basis for an atomic superconducting quantum interference device (SQUID) and ultimately for the realization of atom circuits.

  2. Spectroscopy, Manipulation and Trapping of Neutral Atoms, Molecules, and Other Particles using Optical Nanofibers: A Review

    Morrissey, Michael J; Frawley, Mary; Kumar, Ravi; Prel, Eugen; Russell, Laura; Truong, Viet Giang; Chormaic, Síle Nic

    2013-01-01

    The use of tapered optical fibers, i.e., optical nanofibers, for spectroscopy and the detection of small numbers of particles, such as neutral atoms or molecules, has been gaining ground in recent years. In this review, we briefly introduce the optical nanofiber, its fabrication and optical mode propagation within. We discuss recent progress on the integration of optical nanofibers into laser-cooled atom and vapor systems, paying particular attention to spectroscopy, cold atom cloud characterization and optical trapping schemes. Next, a natural extension on this work to molecules will be introduced. Finally, we consider several alternatives to optical nanofibers that display some advantages for particular applications.

  3. Coherence of a qubit stored in Zeeman levels of a single optically trapped atom

    Rosenfeld, Wenjamin; Weber, Markus; Weinfurter, Harald

    2011-01-01

    We experimentally investigate the coherence properties of a qubit stored in the Zeeman substates of the 5S1/2, F=1 hyperfine ground level of a single optically trapped Rb-87 atom. Larmor precession of a single atomic spin-1 system is observed by preparing the atom in a defined initial spin-state and then measuring the resulting state after a programmable period of free evolution. Additionally, by performing quantum state tomography, maximum knowledge about the spin coherence is gathered. By using an active magnetic field stabilization and without application of a magnetic guiding field we achieve transverse and longitudinal dephasing times of T2*=75..150 \\mus and T1>0.5 ms respectively. We derive the light-shift distribution of a single atom in the approximately harmonic potential of a dipole trap and show that the measured atomic spin coherence is limited mainly by residual position- and state-dependent effects in the optical trapping potential. The improved understanding enables longer coherence times, an i...

  4. Surpassing the mass restriction of buffer gas cooling: Cooling of low mass ions by localized heavier atoms

    Dutta, Sourav; Sawant, Rahul; Rangwala, S. A.

    2016-05-01

    Cooling of trapped ions has resulted in fascinating science including the realization of some of the most accurate atomic clocks. It has also found widespread application, for example, in mass spectrometry and cold chemistry. Among the different methods for cooling ions, cooling by elastic collisions with ultracold neutral atoms is arguably the most generic. However, in spite of its widespread application, there is confusion with regards the collisional heating/cooling of light ions by heavier neutral atoms. We address the question experimentally and demonstrate, for the first time, cooling of light ions by co-trapped heavy atoms. We show that trapped 39 K+ ions are cooled by localized ultracold neutral 85 Rb atoms. The atom-ion mass ratio (= 2.18) is well beyond any theoretical predictions so far. We further argue that cooling of ions by localized cold atoms is possible for any mass ratio. The result opens up the possibility of reaching the elusive s-wave collision regime in atom-ion collisions. S.D. is supported by DST-INSPIRE Faculty Fellowship, India.

  5. A comparison of pulsed and continuous atom transfer between two magneto-optical traps

    We present the experimental results for a comparison between pulsed and continuous transfer of cold 87Rb atoms between a vapor chamber magneto-optical trap (VC-MOT) and an ultra-high vacuum magneto-optical trap (UHV-MOT) when using a resonant push beam. We find that employing repetitive cycles of a pulsed and unfocused push beam on an unsaturated VC-MOT cloud results in a significantly higher number of atoms transferred to the UHV-MOT than the number obtained with a continuous push beam focused on a continuous VC-MOT. In pulsed transfer, we find that both the VC-MOT loading duration and the push beam duration play important roles in the transfer process and govern the number of atoms transferred to the UHV-MOT. The parameters and processes affecting the transfer have been investigated and are discussed.

  6. Electrostatic trapping and in situ detection of Rydberg atoms above chip-based transmission lines

    Lancuba, P

    2016-01-01

    Beams of helium atoms in Rydberg-Stark states with principal quantum number $n=48$ and electric dipole moments of 4600~D have been decelerated from a mean initial longitudinal speed of 2000~m/s to zero velocity in the laboratory-fixed frame-of-reference in the continuously moving electric traps of a transmission-line decelerator. In this process accelerations up to $-1.3\\times10^{7}$~m/s$^2$ were applied, and changes in kinetic energy of $\\Delta E_{\\mathrm{kin}}=1.3\\times10^{-20}$~J ($\\Delta E_{\\mathrm{kin}}/e = 83$~meV) per atom were achieved. Guided and decelerated atoms, and those confined in stationary electrostatic traps, were detected in situ by pulsed electric field ionisation. The results of numerical calculations of particle trajectories within the decelerator have been used to characterise the observed deceleration efficiencies, and aid in the interpretation of the experimental data.

  7. Improved atom number with a dual color magneto—optical trap

    We demonstrate a novel dual color magneto—optical trap (MOT), which uses two sets of overlapping laser beams to cool and trap 87Rb atoms. The volume of cold cloud in the dual color MOT is strongly dependent on the frequency difference of the laser beams and can be significantly larger than that in the normal MOT with single frequency MOT beams. Our experiment shows that the dual color MOT has the same loading rate as the normal MOT, but much longer loading time, leading to threefold increase in the number of trapped atoms. This indicates that the larger number is caused by reduced light induced loss. The dual color MOT is very useful in experiments where both high vacuum level and large atom number are required, such as single chamber quantum memory and Bose—Einstein condensation (BEC) experiments. Compared to the popular dark spontaneous-force optical trap (dark SPOT) technique, our approach is technically simpler and more suitable to low power laser systems. (rapid communication)

  8. Improved atom number with a dual color magneto-optical trap

    Cao Qiang; Luo Xin-Yu; Gao Kui-Yi; Wang Xiao-Rui; Chen Dong-Min; Wang Ru-Quan

    2012-01-01

    We demonstrate a novel dual color magneto-optical trap (MOT),which uses two sets of overlapping laser beams to cool and trap 87Rb atoms.The volume of cold cloud in the dual color MOT is strongly dependent on the frequency difference of the laser beams and can be significantly larger than that in the normal MOT with single frequency MOT beams.Our experiment shows that the dual color MOT has the same loading rate as the normal MOT,but much longer loading time,leading to threefold increase in the number of trapped atoms.This indicates that the larger number is caused by reduced light induced loss.The dual color MOT is very useful in experiments where both high vacuum level and large atom number are required,such as single chamber quantum memory and Bose Einstein condensation (BEC) experiments.Compared to the popular dark spontaneous-force optical trap (dark SPOT) technique,our approach is technically simpler and more suitable to low power laser systems.

  9. Absorption spectroscopy of cold caesium atoms confined in a magneto-optical trap

    Yan Shu-Bin; Liu Tao; Geng Tao; Zhang Tian-Cai; Peng Kun-Chi; Wang Jun-Min

    2004-01-01

    Absorption spectra of cold caesium atoms confined in a magneto-optical trap are measured around D2 line at 852nm with a weak probe beam. Absorption reduction dip due to electromagnetically induced transparency (EIT)effect induced by the cooling/trapping field in a V-type three-level system and a gain peak near the cycling transition are clearly observed. Several mechanisms mixed with EIT effect in a normal V-type three-level system are briefly discussed. A simple theoretical analysis based on a dressed-state model is presented for interpretation of the absorption spectra.

  10. Influence of trapping potentials on the phase diagram of bosonic atoms in optical lattices

    We study the effect of external trapping potentials on the phase diagram of bosonic atoms in optical lattices. We introduce a generalized Bose-Hubbard Hamiltonian that includes the structure of the energy levels of the trapping potential, and show that these levels are in general populated both at finite and zero temperature. We characterize the properties of the superfluid transition for this situation and compare them with those of the standard Bose-Hubbard description. We briefly discuss similar behaviors for fermionic systems

  11. Experimental Properties of Optical Phase Conjugation in Cold Atoms in a Magneto-Optical Trap

    We employ a sample of cold 87Rb atoms in a magneto-optical trap to study the impulse responses and spatial characters of backward conjugate waves in a four-wave mixing process. We measure the slow and superluminal group velocities of backward conjugate waves, and find the sensitive variation of the spatial mode of backward waves with the probe-pump detuning and the dependence of the reflectance on the magnetic field, while the trapping magnetic field exists. (fundamental areas of phenomenology(including applications))

  12. The Role of Singular Control in Frictionless Atom Cooling in a Harmonic Trapping Potential

    Stefanatos, Dionisis

    2011-01-01

    In this article we study the frictionless cooling of atoms trapped in a harmonic potential, while minimizing the transient energy of the system. We show that in the case of unbounded control, this goal is achieved by a singular control, which is also the time-minimal solution for a "dual" problem, where the energy is held fixed. In addition, we examine briefly how the solution is modified when there are bounds on the control. The results presented here have a broad range of applications, from the cooling of a Bose-Einstein condensate confined in a harmonic trap to adiabatic quantum computing and finite time thermodynamic processes.

  13. Quantum state transfer between atomic ensembles trapped in separate cavities via adiabatic passage

    Zhang, Chun-Ling; Chen, Mei-Feng

    2015-07-01

    We propose a new approach for quantum state transfer (QST) between atomic ensembles separately trapped in two distant cavities connected by an optical fiber via adiabatic passage. The three-level Λ-type atoms in each ensemble dispersively interact with the nonresonant classical field and cavity mode. By choosing appropriate parameters of the system, the effective Hamiltonian describes two atomic ensembles interacting with “the same cavity mode” and has a dark state. Consequently, the QST between atomic ensembles can be implemented via adiabatic passage. Numerical calculations show that the scheme is robust against moderate fluctuations of the experimental parameters. In addition, the effect of decoherence can be suppressed effectively. The idea provides a scalable way to an atomic-ensemble-based quantum network, which may be reachable with currently available technology. Project supported by the Funding (type B) from the Fujian Education Department, China (Grant No. JB13261).

  14. Temperature and phase-space density of cold atom cloud in a quadrupole magnetic trap

    Ram, S P; Tiwari, S K; Rawat, H S

    2014-01-01

    We present studies on the modifications in temperature, number density and phase-space density when a laser cooled atom cloud from the optical molasses is trapped in a quadrupole magnetic trap. Theoretically it is shown that for a given temperature and size of the cloud from the molasses, the phase-space density in the magnetic trap first increases with magnetic field gradient and then decreases with it, after attaining a maximum value at an optimum value of magnetic field gradient. The experimentally measured variation in phase-space density in the magnetic trap with the magnetic field gradient has shown the similar trend. However, the experimentally measured values of number density and phase-space density are much lower than their theoretically predicted values. This is attributed to the higher experimentally observed temperature in the magnetic trap than the theoretically predicted temperature. Nevertheless, these studies can be useful to set a higher phase-space density in the trap by setting the optimum...

  15. Sub-Doppler Cooling of Neutral Atoms in a Grating Magneto-Optical Trap

    Grover, J. A.; Lee, J.; Orozco, L. A.; Rolston, S. L.

    2013-05-01

    The recent demonstration of a grating magneto-optical trap (GMOT) for 87Rb presents an advancement in the field of atom traps. The system requires only a single beam and three planar diffraction gratings to form an accessible cloud of cold atoms above the plane of the diffractors. Here we demonstrate further sup-Doppler cooling of the atoms to a temperature of 7.6(0.6) μK through a multi-stage, far-detuned MOT in conjunction with optical molasses. A decomposition of the electric field into polarization components for this geometry does not yield a mapping onto standard sub-Doppler cooling configurations. With numerical simulations, we find that the polarization composition of the GMOT optical field, which includes both σ- and π-polarized light, does indeed produce sub-Doppler temperatures. We also discuss the integrability of the GMOT with an optical nanofiber trap as a step towards creating a hybrid quantum system that couples atoms to superconducting circuits. This work is supported by ARO MURI award W911NF0910406 and the NSF Physics Frontier Center at the JQI.

  16. On the combination of a low energy hydrogen atom beam with a cold multipole ion trap

    Borodi, Gheorghe

    2008-12-09

    The first part of the activities of this thesis was to develop a sophisticated ion storage apparatus dedicated to study chemical processes with atomic hydrogen. The integration of a differentially pumped radical beam source into an existing temperature variable 22- pole trapping machine has required major modifications. Since astrophysical questions have been in the center of our interest, the introduction first gives a short overview of astrophysics and -chemistry. The basics of ion trapping in temperature variable rf traps is well-documented in the literature; therefore, the description of the basic instrument (Chapter 2) is kept rather short. Much effort has been put into the development of an intense and stable source for hydrogen atoms the kinetic energy of which can be changed. Chapter 3 describes this module in detail with emphasis on the integration of magnetic hexapoles for guiding the atoms and special treatments of the surfaces for reducing H-H recombination. Due to the unique sensitivity of the rf ion trapping technique, this instrument allows one to study a variety of reactions of astrochemical and fundamental interest. The results of this work are summarized in Chapter 4. Reactions of CO{sub 2}{sup +} with hydrogen atoms and molecules have been established as calibration standard for in situ determination of H and H{sub 2} densities over the full temperature range of the apparatus (10 K-300 K). For the first time, reactions of H- and D-atoms with the ionic hydrocarbons CH{sup +}, CH{sub 2}{sup +}, and CH{sub 4}{sup +} have been studied at temperatures of interstellar space. A very interesting, not yet fully understood collision system is the interaction of protonated methane with H. The outlook presents some ideas, how to improve the new instrument and a few reaction systems are mentioned which may be studied next. (orig.)

  17. On the combination of a low energy hydrogen atom beam with a cold multipole ion trap

    The first part of the activities of this thesis was to develop a sophisticated ion storage apparatus dedicated to study chemical processes with atomic hydrogen. The integration of a differentially pumped radical beam source into an existing temperature variable 22- pole trapping machine has required major modifications. Since astrophysical questions have been in the center of our interest, the introduction first gives a short overview of astrophysics and -chemistry. The basics of ion trapping in temperature variable rf traps is well-documented in the literature; therefore, the description of the basic instrument (Chapter 2) is kept rather short. Much effort has been put into the development of an intense and stable source for hydrogen atoms the kinetic energy of which can be changed. Chapter 3 describes this module in detail with emphasis on the integration of magnetic hexapoles for guiding the atoms and special treatments of the surfaces for reducing H-H recombination. Due to the unique sensitivity of the rf ion trapping technique, this instrument allows one to study a variety of reactions of astrochemical and fundamental interest. The results of this work are summarized in Chapter 4. Reactions of CO2+ with hydrogen atoms and molecules have been established as calibration standard for in situ determination of H and H2 densities over the full temperature range of the apparatus (10 K-300 K). For the first time, reactions of H- and D-atoms with the ionic hydrocarbons CH+, CH2+, and CH4+ have been studied at temperatures of interstellar space. A very interesting, not yet fully understood collision system is the interaction of protonated methane with H. The outlook presents some ideas, how to improve the new instrument and a few reaction systems are mentioned which may be studied next. (orig.)

  18. In situ atom trapping of Bi on W-coated slotted quartz tube flame atomic absorption spectrometry and interference studies

    Analytical performances of metal coated slotted quartz tube flame atomic absorption spectrometry (SQT-FAAS) and slotted quartz tube in situ atom trapping flame atomic absorption spectrometry (SQT-AT-FAAS) systems were evaluated for determination of Bi. Non-volatile elements such as Mo, Zr, W and Ta were tried as coating materials. It was observed that W-coated SQT gave the best sensitivity for the determination of Bi for SQT-FAAS and SQT-AT-FAAS. The parameters for W-coated SQT-FAAS and W-coated SQT-AT-FAAS were optimized. Sensitivity of FAAS for Bi was improved as 4.0 fold by W-coated SQT-FAAS while 613 fold enhancement in sensitivity was achieved by W-coated SQT-AT-FAAS using 5.0 min trapping with respect to conventional FAAS. MIBK was selected as organic solvent for the re-atomization of Bi from the trapping surface. Limit of detection values for W-coated SQT-FAAS and W-coated SQT-AT-FAAS was obtained as 0.14 μg mL−1 and 0.51 ng mL−1, respectively. Linear calibration plot was obtained in the range of 2.5–25.0 ng mL−1 for W-coated SQT-AT-FAAS. Accuracy of the W-coated SQT-AT-FAAS system was checked by analyzing a standard reference material, NIST 1643e. - Highlights: • Further increasing in sensitivity of SQT-AT-FAAS was obtained by using a W coated SQT. • 613 fold sensitivity enhancement was achieved by W coated SQT-AT-FAAS versus FAAS. • A sensitive, rapid and simple technique for Bi was developed with an LOD of 0.51 ng mL−1. • The technique is suggested for laboratories equipped with only a flame AA spectrometer

  19. Trapping of atomic hydrogen in octasilsesquioxane cages by glow discharge treatment

    Hydrogen atoms are trapped in octasilsesquioxane ((RSiO3/2)8, R = H, CH3, i-butyl, etc.) cages by electric discharge treatment. The yield of the trapped hydrogen was evaluated to be 1.3 x 10-4 of cage unit by using ESR spectroscopy for (CH3SiO3/2)8 discharged for 4 minutes at room temperature. To obtain a comparable yield of the trapped hydrogen by γ-rays (60Co) irradiation, an absorbed dose of ca. 300 kGy is required, taking two days or more in general. The discharge technique is simple and extremely efficient compared to the conventional method of γ-ray radiolysis. (author)

  20. Magneto-optical trapping of 88Sr atoms with 689 nm laser

    We report the experimental realization of strontium magneto-optical trap (MOT) operating on the intercombination transition 1S0-3P1 at 689 nm, namely red MOT. A 689 nm laser used for cooling and trapping is injection locked to a master laser, whose linewidth is narrowed to 150 Hz by locking to a high finesse optical reference cavity. 88Sr atoms pre-cooled and trapped by the broad 1S0-1P1 transition at 461 nm are transferred to the red MOT with the help of a time sequence controller. The transfer ratio is about 20% and the red MOT's temperature is estimated to be less than 20 μK by the time-of-flight (TOF) image analysis. (authors)

  1. Magneto-Optical Trapping of 88Sr atoms with 689 nm Laser

    WANG Qiang; LIN Bai-Ke; ZHAO Yang; LI Ye; WANG Shao-Kai; WANG Min-Ming; ZANG Er-Jun; LI Tian-Chu; FANG Zhan-Jun

    2011-01-01

    We report the experimental realization of strontium magneto-optical trap(MOT) operating on the intercombination transition lSo-3 P1 at 689nm, namely red MOT. A 689nm laser used for cooling and trapping is injection locked to a master laser, whose linewidth is narrowed to 150 Hz by locking to a high finesse optical reference cavity.88 Sr atoms pre-cooled and trapped by the broad 1SO-1 Pl transition at 461 nm are transferred to the red MOT with the help of a time sequence controller. The transfer ratio is about 20% and the red MOT's temperature is estimated to be less than 20 μK by the time-of-flight(TOF) image analysis.

  2. Ultratrace determination of lead by hydride generation in-atomizer trapping atomic absorption spectrometry: Optimization of plumbane generation and analyte preconcentration in a quartz trap-and-atomizer device

    Kratzer, Jan

    71-72, MAY-JUN (2012), s. 40-47. ISSN 0584-8547 R&D Projects: GA ČR(CZ) GPP206/11/P002 Institutional support: RVO:68081715 Keywords : hydride generation AAS * lead determination * trap-and-atomizer device Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.141, year: 2012

  3. Optical trapping of cold neutral atoms using a two-color evanescent light field around a carbon nanotube

    We suggest a new schema of trapping cold atoms using a two-color evanescent light field around a carbon nanotube. The two light fields circularly polarized sending through a carbon nanotube generates an evanescent wave around this nanotube. By evanescent effect, the wave decays away from the nanotube producing a set of trapping minima of the total potential in the transverse plane as a ring around the nanotube. This schema allows capture of atoms to a cylindrical shell around the nanotube. We consider some possible boundary conditions leading to the non-trivial bound state solution. Our result will be compared to some recent trapping models and our previous trapping models.

  4. Measuring isospin mixing in 36Ar using a polarized, neutral atom trap

    Magneto-optical traps provide a cold, compact cloud of radioactive atoms and therefore are an ideal source for use in precision nuclear β decay studies. Optical pumping techniques can add a new dimension to such experiments by efficiently polarizing these samples to ≤99%. TRIUMF's experiment E925 is utilizing these techniques to prepare to measure the isospin mixing between the first two Iπ=2+ excited states of 36Ar with the lowest 2+, T=1 isobaric analog state. The spin-polarized 36K β+ decay observables will be measured using TRIUMF's neutral atom trap at ISAC, TRIUMF's isotope separator and accelerator facility. The main purpose is to test isospin mixing models in the s,d-shell needed for determination of the superallowed Fermi strength in 0+ → 0+ decays

  5. Narrow-line magneto-optical cooling and trapping of strongly magnetic atoms

    Berglund, Andrew J; McClelland, Jabez J

    2008-01-01

    Laser cooling on weak transitions is a useful technique for reaching ultracold temperatures in atoms with multiple valence electrons. However, for strongly magnetic atoms a conventional narrow-line magneto-optical trap (MOT) is destabilized by competition between optical and magnetic forces. We overcome this difficulty in Er by developing an unusual narrow-line MOT that balances optical and magnetic forces using laser light tuned to the blue side of a narrow (8 kHz) transition. The trap population is spin-polarized with temperatures reaching below 2 microkelvin. Our results constitute an alternative method for laser cooling on weak transitions, applicable to rare-earth-metal and metastable alkaline earth elements.

  6. Atomic origin of high-temperature electron trapping in metal-oxide-semiconductor devices

    Shen, Xiao, E-mail: xiao.shen@vanderbilt.edu [Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States); Dhar, Sarit [Department of Physics, Auburn University, Auburn, Alabama 36849 (United States); Pantelides, Sokrates T. [Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States); Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennessee 37235 (United States); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2015-04-06

    MOSFETs based on wide-band-gap semiconductors are suitable for operation at high temperature, at which additional atomic-scale processes that are benign at lower temperatures can get activated, resulting in device degradation. Recently, significant enhancement of electron trapping was observed under positive bias in SiC MOSFETs at temperatures higher than 150 °C. Here, we report first-principles calculations showing that the enhanced electron trapping is associated with thermally activated capturing of a second electron by an oxygen vacancy in SiO{sub 2} by which the vacancy transforms into a structure that comprises one Si dangling bond and a bond between a five-fold and a four-fold Si atoms. The results suggest a key role of oxygen vacancies and their structural reconfigurations in the reliability of high-temperature MOS devices.

  7. Developing Density of Laser-Cooled Neutral Atoms and Molecules in a Linear Magnetic Trap

    Velasquez, Joe, III; Walstrom, Peter; di Rosa, Michael

    2013-05-01

    In this poster we show that neutral particle injection and accumulation using laser-induced spin flips may be used to form dense ensembles of ultracold magnetic particles, i.e., laser-cooled paramagnetic atoms and molecules. Particles are injected in a field-seeking state, are switched by optical pumping to a field-repelled state, and are stored in the minimum-B trap. The analogous process in high-energy charged-particle accumulator rings is charge-exchange injection using stripper foils. The trap is a linear array of sextupoles capped by solenoids. Particle-tracking calculations and design of our linear accumulator along with related experiments involving 7Li will be presented. We test these concepts first with atoms in preparation for later work with selected molecules. Finally, we present our preliminary results with CaH, our candidate molecule for laser cooling. This project is funded by the LDRD program of Los Alamos National Laboratory.

  8. A highly miniaturized vacuum package for a trapped ion atomic clock

    Schwindt, Peter D. D.; Jau, Yuan-Yu; Partner, Heather; Casias, Adrian; Wagner, Adrian R.; Moorman, Matthew; Manginell, Ronald P.; Kellogg, James R.; Prestage, John D.

    2016-05-01

    We report on the development of a highly miniaturized vacuum package for use in an atomic clock utilizing trapped ytterbium-171 ions. The vacuum package is approximately 1 cm3 in size and contains a linear quadrupole RF Paul ion trap, miniature neutral Yb sources, and a non-evaporable getter pump. We describe the fabrication process for making the Yb sources and assembling the vacuum package. To prepare the vacuum package for ion trapping, it was evacuated, baked at a high temperature, and then back filled with a helium buffer gas. Once appropriate vacuum conditions were achieved in the package, it was sealed with a copper pinch-off and was subsequently pumped only by the non-evaporable getter. We demonstrated ion trapping in this vacuum package and the operation of an atomic clock, stabilizing a local oscillator to the 12.6 GHz hyperfine transition of 171Y b+. The fractional frequency stability of the clock was measured to be 2 × 10-11/τ1/2.

  9. High-Resolution Imaging and Optical Control of Bose-Einstein Condensates in an Atom Chip Magnetic Trap

    Salim, Evan A; Pfeiffer, Jonathan B; Anderson, Dana Z

    2012-01-01

    A high-resolution projection and imaging system for ultracold atoms is implemented using a compound silicon and glass atom chip. The atom chip is metalized to enable magnetic trapping while glass regions enable high numerical aperture optical access to atoms residing in the magnetic trap about 100 microns below the chip surface. The atom chip serves as a wall of the vacuum system, which enables the use of commercial microscope components for projection and imaging. Holographically generated light patterns are used to optically slice a cigar-shaped magnetic trap into separate regions; this has been used to simultaneously generate up to four Bose-condensates. Using fluorescence techniques we have demonstrated in-trap imaging resolution down to 2.5 microns

  10. Highly collimated source of cold Rubidium atoms from a two dimensional magneto-optical trap

    Carrat, Vincent; Jacquey, Marion; Tabosa, José W; de Lesegno, Bruno Viaris; Pruvost, Laurence

    2013-01-01

    Using a blue detuned laser shaped in a Laguerre-Gaussian donut mode we highly collimate the output of a two dimensional magneto-optical trap. The resulting atomic beam has a 1 mm diameter, its divergence is reduced from 40 down to 3 mrad and the atomic density is increased by a factor of 200. The collimation effect has been studied versus the order of the Laguerre-Gaussian mode (up to 10) and the laser atom frequency detuning (2 to 120 GHz). The 2D-colli-MOT study allows us to determine the best conditions which minimize the atom heating due to residual light absorption and optimize the collimation effect. The 2D-colli MOT could provide a new tool to fill a 3D-MOT using lasers with millimeter range diameters and thus sparing the laser power.

  11. Control of light trapping in a large atomic system by a static magnetic field

    Skipetrov, S E; Havey, M D

    2016-01-01

    We propose to control light trapping in a large ensemble of cold atoms by an external, static magnetic field. For an appropriate choice of frequency and polarization of the exciting pulse, the field is expected to speed up the fluorescence of a dilute atomic system but can significantly slow it down in a dense ensemble. The slowing down of fluorescence is due to the excitation of spatially localized collective atomic states that appear only under a strong magnetic field and have exponentially long lifetimes. The control of fluorescence by the magnetic field may be of interest for use in future quantum-information processing devices. It also paves a way towards the experimental observation of the disorder-induced localization of light in cold atomic systems.

  12. Core-Shell Magneto-Optical Trap for Alkaline-Earth-Metal-Like Atoms

    Lee, Jeongwon; Noh, Jiho; Mun, Jongchul

    2014-01-01

    We propose and demonstrate a new magneto-optical trap (MOT) for alkaline-earth-metal-like (AEML) atoms where the narrow $^{1}S_{0}\\rightarrow$$^{3}P_{1}$ transition and the broad $^{1}S_{0}\\rightarrow$$^{1}P_{1}$ transition are spatially arranged into a core-shell configuration. Our scheme resolves the main limitations of previously adopted MOT schemes, leading to a significant increase in both the loading rate and the steady state atom number. We apply this scheme to $^{174}$Yb MOT, where we show about a hundred-fold improvement in the loading rate and ten-fold improvement in the steady state atom number compared to reported cases that we know of to date. This technique could be readily extended to other AEML atoms to increase the statistical sensitivity of many different types of precision experiments.

  13. Generation of a cold pulsed beam of Rb atoms by transfer from a 3D magneto-optic trap

    Chanu, Sapam Ranjita; Natarajan, Vasant

    2016-01-01

    We demonstrate a technique for producing a cold pulsed beam of atoms by transferring a cloud of atoms trapped in a three dimensional magneto-optic trap (MOT). The MOT is loaded by heating a getter source of Rb atoms. We show that it is advantageous to transfer with two beams (with a small angle between them) compared to a single beam, because the atoms stop interacting with the beams in the two-beam technique, which results in a Gaussian velocity distribution. The atoms are further cooled in optical molasses by turning off the MOT magnetic field before the transfer beams are turned on.

  14. Generation of a cold pulsed beam of Rb atoms by transfer from a 3D magneto-optic trap

    Chanu, Sapam Ranjita; Rathod, Ketan D.; Natarajan, Vasant

    2016-08-01

    We demonstrate a technique for producing a cold pulsed beam of atoms by transferring a cloud of atoms trapped in a three dimensional magneto-optic trap (MOT). The MOT is loaded by heating a getter source of Rb atoms. We show that it is advantageous to transfer with two beams (with a small angle between them) compared to a single beam, because the atoms stop interacting with the beams in the two-beam technique, which results in a Gaussian velocity distribution. The atoms are further cooled in optical molasses by turning off the MOT magnetic field before the transfer beams are turned on.

  15. Formation of molecular ions by radiative association of cold trapped atoms and ions

    Silva Jr, Humberto Da; Raoult, Maurice; Aymar, Mireille; Dulieu, Olivier

    2015-01-01

    Radiative emission during cold collisions between trapped laser-cooled Rb atoms and alkaline-earth ions (Ca$^+$, Sr$^+$, Ba$^+$) and Yb$^+$, and between Li and Yb$^+$, are studied theoretically, using accurate effective-core-potential based quantum chemistry calculations of potential energy curves and transition dipole moments of the related molecular ions. Radiative association of molecular ions is predicted to occur for all systems with a cross section two to ten times larger than the radia...

  16. Electrochemical selenium hydride generation with in situ trapping in graphite tube atomizers

    Šíma, Jan; Rychlovský, P.

    2003-01-01

    Roč. 58, č. 5 (2003), s. 919-930. ISSN 0584-8547 R&D Projects: GA ČR GA203/98/0754; GA ČR GA203/01/0453 Institutional research plan: CEZ:AV0Z4031919 Keywords : hydride generation * electrothermal atomic absorption spectrometry * In situ trapping Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.361, year: 2003

  17. Detecting atoms trapped in an optical lattice using a tapered optical nanofiber

    Hennessy, T

    2014-01-01

    Optical detection of structures with dimensions smaller than an optical wavelength requires devices that work on scales beyond the diffraction limit. Here we present the possibility of using a tapered optical nanofiber as a detector to resolve individual atoms trapped in an optical lattice in the Mott Insulator phase. We show that the small size of the fiber combined with an enhanced photon collection rate can allow for the attainment of large and reliable measurement signals.

  18. Production and trapping of radioactive atoms at the TRI\\muP facility

    Traykov, E.; Dammalapati, U.; De, S.; Dermois, O. C.; Huisman, L.; Jungmann, K.; Kruithof, W.; Mol, A. J.; Onderwater, C.J.G.(Van Swinderen Institute, University of Groningen, Groningen, The Netherlands); Rogachevskiy, A.; Silva, M. da Silva e; Sohani, M.; Versolato, O.; Willmann, L.; Wilschut, H.W.

    2007-01-01

    The structures for the TRI$\\mu$P facility have been completed and commissioned. At the facility radioactive nuclides are produced to study fundamental interactions and symmetries. An important feature is the possibility to trap radioactive atoms in order to obtain and hold a pure substrate-free sample for precision measurements. In the TRI$\\mu$P facility a production target is followed by a magnetic separator, where radioactive isotopes are produced in inverse reaction kinematics. Separation ...

  19. Coherent-population-trapping resonances with linearly polarized light for all-optical miniature atomic clocks

    We present a joint theoretical and experimental characterization of the coherent population trapping (CPT) resonance excited on the D1 line of 87Rb atoms by bichromatic linearly polarized laser light. We observe high-contrast transmission resonances (up to ≅25%), which makes this excitation scheme promising for miniature all-optical atomic clock applications. We also demonstrate cancellation of the first-order light shift by proper choice of the frequencies and relative intensities of the two laser-field components. Our theoretical predictions are in good agreement with the experimental results.

  20. Incomplete optical shielding in cold atom traps: three-dimensional Landau-Zener theory

    Ultracold atom collisions in the presence of a linearly polarized blueshifted laser field are studied theoretically. An analytical solution is presented within the framework of the Landau-Zener approximation. The effect of incomplete shielding is mostly accounted for by incorporating the three-dimensional character of the collisions, using a partial-wave analysis with space degeneracy. A model of two electronic states, including effects of indistinguishability of the colliding atoms, is used. The model associates the incomplete shielding with a process involving two crossing points. The theory is applied to the case of metastable xenon traps, obtaining a fair agreement with the experimental data. copyright 1997 The American Physical Society

  1. Optical resonator for a standing wave dipole trap for fermionic lithium atoms

    This thesis reports on the the construction of an optical resonator for a new resonator dipole trap to store the fermionic 6Li-isotope and to investigate its scattering properties. It was demonstrated that the resonator enhances the energy density of a (1064 nm and 40 mW) laser beam by a factor of more than 100. A fused silica vacuum cell is positioned inside the resonator under Brewster's angle. The losses of the resonator depend mainly on the optical quality of the cell. The expected trap depth of the dipole trap is 200 μK and the photon scattering rate is expected to be about 0.4 s-1. The resonator is stabilized by means of a polarization spectroscopy method. Due to high trap frequencies, which are produced by the tight enclosure of the standing wave in the resonator, the axial motion must be quantized. A simple model to describe this quantization has been developed. A magneto-optical trap, which serves as a source of cold lithium atoms, was put in operation. (orig.)

  2. Towards hybrid quantum systems: Trapping a single atom near a nanoscale solid-state structure

    Tiecke T.G.

    2013-08-01

    Full Text Available We describe and demonstrate a method to deterministically trap single atoms near nanoscale solid-state objects. The trap is formed by the interference of an optical tweezer and its reflection from the nano object, creating a one-dimensional optical lattice where the first lattice site is at z0 ∼ λ/4 from the surface. Using a tapered optical fiber as the nanoscopic object, we characterize the loading into different lattice sites by means of the AC-Stark shift induced by a guided fiber mode. We demonstrate a loading efficiency of 94(6% into the first lattice site, and measure the cooperativity for the emission of the atom into the guided mode of the nanofiber. We show that by tailoring the dimensions of the nanofiber the distance of the trap to the surface can be adjusted. This method is applicable to a large variety of nanostructures and represents a promising starting point for interfacing single atoms with arbitrary nanoscale solid-state systems.

  3. Intense source of cold Rb atoms from a pure two-dimensional magneto-optical trap

    We present a two-dimensional (2D) magneto-optical trap (MOT) setup for the production of a continuous collimated beam of cold 87Rb atoms out of a vapor cell. The underlying physics is purely two-dimensional cooling and trapping, which allows for a high flux of up to 6x1010 atoms/s and a small divergence of the resulting beam. We analyze the velocity distribution of the 2D MOT. The longitudinal velocity distribution of the atomic beam shows a broad feature (full width at half maximum ≅75 m/s), centered around 50 m/s. The dependence of the flux on laser intensity, on geometry of the trapping volume, and on pressure in the vapor cell was investigated in detail. The influence of the geometry of the 2D MOT on the mean velocity of the cold beam has been studied. We present a simple model for the velocity distribution of the flux based on rate equations describing the general features of our source

  4. A=225 implantation for $^{221}$Fr source for TRIUMF atom trap

    The FrPNC Collaboration is mounting an atom trap for parity violation experiments and precision spectroscopy on francium atoms at TRIUMF's ISAC facility. We would like to use ISOLDE's capability of simultaneously implanting A=225 (while another experiment runs online) to make a long-lived source feeding $^{221}$Fr for tests of the trap. $^{225}$Ra $\\beta$-decays to $^{225}$Ac, which then $\\alpha$-decays, producing 100 keV $^{221}$Fr t$_{1/2}$= 4.8 minute recoils. The implanted A=225 source would be shipped to TRIUMF, where it would be held for several minutes at a time a few mm from the same yttrium foil that normally receives the ISAC beam. SRIM calculations imply that 20% of the $^{221}$Fr will be implanted in a 1 cm diameter spot on the yttrium. Then the yttrium foil is moved to the trap and heated to release the Fr atoms, just as in normal ISAC online operation. A test implantation will be done at 10$^{7}$/sec production for 1 day, testing whether carbon cracking on the implantation foil in the mass separ...

  5. Measurement of Absolute Atomic Collision Cross Section with Helium Using 87Rb Atoms Confined in Magneto-Optic and Magnetic Traps

    WANG Ji-Cheng; ZHOU Ke-Ya; WANG Yue-Yuan; LIAO Qing-Hong; LIU Shu-Tian

    2011-01-01

    We present the measurements and calculations of the absolute total collision cross sections for a room-temperature gas of helium using 87 Rb atoms confined in either a magneto-optic or a magnetic quadrupole trap. The loss rates from the magneto-optic trap and the pure magnetic trap are compared and show significant differences. The collision cross sections as a function of trap depth for helium gas are obtained. These findings are significant for extracting the information about the different cross sections when the trap depth is changed.%@@ We present the measurements and calculations of the absolute total collision cross sections for a room-temperature gas of helium using 87Rb atoms confined in either a magneto-optic or a magnetic quadrupole trap.The loss rates from the magneto-optic trap and the pure magnetic trap are compared and show significant differences.The collision cross sections as a function of trap depth for helium gas are obtained.These findings are significant for extracting the information about the different cross sections when the trap depth is changed.

  6. Atom trapping and guiding with a subwavelength-diameter optical fiber

    We suggest using an evanescent wave around a thin fiber to trap atoms. We show that the gradient force of a red-detuned evanescent-wave field in the fundamental mode of a silica fiber can balance the centrifugal force when the fiber diameter is about two times smaller than the wavelength of the light and the component of the angular momentum of the atoms along the fiber axis is in an appropriate range. As an example, the system should be realizable for cesium atoms at a temperature of less than 0.29 mK using a silica fiber with a radius of 0.2 μm and a 1.3-μm-wavelength light with a power of about 27 mW

  7. Large Bragg Reflection from One-Dimensional Chains of Trapped Atoms Near a Nanoscale Waveguide

    Corzo, N V; Chandra, A; Goban, A; Sheremet, A S; Kupriyanov, D V; Laurat, J

    2016-01-01

    We report experimental observations of large Bragg reflection from arrays of cold atoms trapped near a one-dimensional nanoscale waveguide. By using an optical lattice in the evanescent field surrounding a nanofiber with a period close to commensurate with the resonant wavelength, we observe a reflectance up to 75% for the guided mode. Each atom behaves as a partially-reflecting mirror and an ordered chain of about 2000 atoms is sufficient to realize an efficient Bragg mirror. Measurements of the reflection spectra as a function of the lattice period and the probe polarization are reported. The latter shows the effect of the chiral character of nanoscale waveguides on this reflection. The ability to control photon transport in 1D waveguides coupled to spin systems would allow for novel quantum network capabilities and many-body effects emerging from long-range interactions.

  8. Precision spectroscopy of Mg atoms in a magneto-optical trap

    Goncharov, A N; Brazhnikov, D V; Shilov, A M; Bagayev, S N [Novosibirsk State University, Novosibirsk (Russian Federation); Bonert, A E [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2014-06-30

    We report the results of experimental investigations aimed at creation of the optical frequency standard based on magnesium atoms cooled and localised in a magneto-optical trap (MOT). An experimentally realised MOT for magnesium made it possible to obtain a cloud comprising ∼10{sup 6} – 10{sup 7} atoms at a temperature of 3 – 5 mK. The results of ultra-high resolution spectroscopy of intercombination {sup 1}S{sub 0} – {sup 3}P{sub 1} transition for Mg atom are presented, the resonances in time-domain separated optical fields with the half-width of Γ = 500 Hz are recorded, which corresponds to the Q-factor of the reference line Q = ν/Δν ∼ 1.3 × 10{sup 12}. (extreme light fields and their applications)

  9. Collisional and Radiative Processes in Adiabatic Deceleration, Deflection, and Off-Axis Trapping of a Rydberg Atom Beam

    A supersonic beam of Rydberg hydrogen atoms has been adiabatically deflected by 90 deg., decelerated to zero velocity in less than 25 μs, and loaded into an electric trap. The deflection has allowed the suppression of collisions with atoms in the trailing part of the gas pulse. The processes leading to trap losses, i.e., fluorescence to the ground state, and transitions and ionization induced by blackbody radiation have been monitored over several milliseconds and quantitatively analyzed.

  10. Vacancy trapping behaviors of hydrogen atoms in Ti3SiC2: a first-principles study

    Xu, Yi-Guo; Ou, Xue-Dong; Rong, Xi-Ming

    2013-01-01

    The behaviors of hydrogen (H) in MAX phase material Ti3SiC2 have been investigated using first-principles method. We show that a single H atom prefers to stay 1.01 {\\AA} down of the Si vacancy with solution energy of about -4.07 eV, lowerthan that in bulk Ti3SiC2. Multi H atoms exhibit a repulsive interaction at the Si vacancy. And up to five H atoms can be trapped by a Si vacancy without H2 molecules formation. These results suggest the strong vacancy trapping characteristic of H atoms in Ti...

  11. Ti–Al–O nanocrystal charge trapping memory cells fabricated by atomic layer deposition

    Charge trapping memory cells using Ti–Al–O (TAO) film as charge trapping layer and amorphous Al2O3 as the tunneling and blocking layers were fabricated on Si substrates by atomic layer deposition method. As-deposited TAO films were annealed at 700 °C, 800 °C and 900 °C for 3 min in N2 with a rapid thermal annealing process to form nanocrystals. High-resolution transmission electron microscopy and X-ray photoelectron spectroscopy were used to characterize the microstructure and band diagram of the heterostructures. The electrical characteristics and charge storage properties of the Al2O3/TAO/Al2O3/Si stack structures were also evaluated. Compared to 700 °C and 900 °C samples, the memory cells annealed at 800 °C exhibit better memory performance with larger memory window of 4.8 V at ± 6 V sweeping, higher program/erase speed and excellent endurance. - Highlights: • The charge trapping memory cells were fabricated by atomic layer deposition method. • The anneal temperature plays a key role in forming nanocrystals. • The memory cells annealed at 800 °C exhibit better memory performance. • The band alignment is beneficial to enhance the retention characteristics

  12. In situ atom trapping of Bi on W-coated slotted quartz tube flame atomic absorption spectrometry and interference studies

    Kılınç, Ersin, E-mail: kilincersin@gmail.com [Medical Laboratory Techniques, Vocational Higher School of Healthcare Studies, Mardin Artuklu University, 47200 Mardin (Turkey); Bakırdere, Sezgin [Yıldız Technical University, Art and Science Faculy, Department of Chemistry, Esenler, TR 34220 İstanbul (Turkey); Aydın, Fırat [Dicle University, Faculty of Science, Department of Chemistry, Laboratory of Chemical Analysis, TR 21280 Diyarbakır (Turkey); Ataman, O. Yavuz [Middle East Technical University, Faculty of Arts and Sciences, Department of Chemistry, 06800 Ankara (Turkey)

    2013-11-01

    Analytical performances of metal coated slotted quartz tube flame atomic absorption spectrometry (SQT-FAAS) and slotted quartz tube in situ atom trapping flame atomic absorption spectrometry (SQT-AT-FAAS) systems were evaluated for determination of Bi. Non-volatile elements such as Mo, Zr, W and Ta were tried as coating materials. It was observed that W-coated SQT gave the best sensitivity for the determination of Bi for SQT-FAAS and SQT-AT-FAAS. The parameters for W-coated SQT-FAAS and W-coated SQT-AT-FAAS were optimized. Sensitivity of FAAS for Bi was improved as 4.0 fold by W-coated SQT-FAAS while 613 fold enhancement in sensitivity was achieved by W-coated SQT-AT-FAAS using 5.0 min trapping with respect to conventional FAAS. MIBK was selected as organic solvent for the re-atomization of Bi from the trapping surface. Limit of detection values for W-coated SQT-FAAS and W-coated SQT-AT-FAAS was obtained as 0.14 μg mL{sup −1} and 0.51 ng mL{sup −1}, respectively. Linear calibration plot was obtained in the range of 2.5–25.0 ng mL{sup −1} for W-coated SQT-AT-FAAS. Accuracy of the W-coated SQT-AT-FAAS system was checked by analyzing a standard reference material, NIST 1643e. - Highlights: • Further increasing in sensitivity of SQT-AT-FAAS was obtained by using a W coated SQT. • 613 fold sensitivity enhancement was achieved by W coated SQT-AT-FAAS versus FAAS. • A sensitive, rapid and simple technique for Bi was developed with an LOD of 0.51 ng mL{sup −1}. • The technique is suggested for laboratories equipped with only a flame AA spectrometer.

  13. Universal Two-Body Spectra of Ultracold Harmonically Trapped Atoms in Two and Three Dimensions

    Zinner, Nikolaj Thomas

    2012-01-01

    We consider the spectrum of two ultracold harmonically trapped atoms interacting via short-range interactions. The Green's function approach is used to unify the two and three dimensional cases. We derive criteria for the universality of the spectrum, i.e. its independence of the details of the...... short-range interaction. The results in three dimensions are examplified for narrow s-wave Feshbach resonances and we show how effective range corrections can modify the rearrangement of the level structure. However, this requires extremely narrow resonances or very tight traps that are not currently...... experimentally available. In the two-dimensional case we discuss the p-wave channel in detail and demonstrate how the non-universality of the spectrum arises within the Green's function approach. We then show that the spectrum is not particularly sensitive to the short-distance details in the case when the two...

  14. Magneto optical trap recoil ion momentum spectroscopy: application to ion-atom collisions

    87Rb atoms have been cooled, trapped and prepared as targets for collision studies with 2 and 5 keV Na+ projectiles. The physics studied deals with charge exchange processes. The active electron, which is generally the most peripheral electron of the atomic target, is transferred from the target onto the ionic projectile. The ionized target is called recoil ion. The technique used to study this physics is the MOTRIMS (Magneto Optical Trap Recoil Ion Momentum Spectroscopy) technique, which combines a magneto optical trap and a recoil ion momentum spectrometer. The spectrometer is used for the measurement of the recoil ions momentum, which gives access to all the information of the collision: the Q-value (which is the potential energy difference of the active electron on each particle) and the scattering angle of the projectile. The trap provides extremely cold targets to optimize the measurement of the momentum, and to release the latter from thermal motion. Through cinematically complete experiments, the MOTRIMS technique gives access to better resolutions on momentum measurements. Measurements of differential cross sections in initial and final capture states and in scattering angle have been done. Results obtained for differential cross sections in initial and final states show globally a good agreement with theory and an other experiment. Nevertheless, discrepancies with theory and this other experiment are shown for the measurements of doubly differential cross sections. These discrepancies are not understood yet. The particularity of the experimental setup designed and tested in this work, namely a low background noise, allows a great sensitivity to weak capture channels, and brings a technical and scientific gain compared with previous works. (author)

  15. Trapping of low temperature irradiation produced interstitial atoms at 57Co in Al

    The Moessbauer effect was used in studying the microscopic properties of lattice defects in Al. A 57Co in Al Moessbauer source was irradiated at 4.6 K with fast neutrons to produce lattice defects. Moessbauer spectra were taken before irradiation, after irradiation and during annealing at various temperatures. After irradiation a new peak appeared which first increased with the temperature of annealing, reached its maximum at 160 K and disappeared during annealing at 250 K. The new line was interpreted as being due to the interstitial Al atoms trapped at 57Co impurities. (A.K.)

  16. Quantum Degenerate Fermi-Bose Mixtures of 40K and 87Rb Atoms in a Quadrupole-Ioffe Configuration Trap

    XIONG De-Zhi; CHEN Hai-Xia; WANG Peng-Jun; YU Xu-Dong; GAO Feng; ZHANG Jing

    2008-01-01

    @@ We report on the attainment of quantum degeneracy of 40K by means of efficient thermal collisions with the evaporatively cooled 87Rb atoms.In a quadrupole-Ioffe configuration trap,potassium atoms are cooled to 0.5 times the Fermi temperature.We obtain up to 7.59 × 105 degenerate fermions 40K.

  17. Direct Observation of Coherent Population Trapping in a Superconducting Artificial Atom

    Kelly, William R; Ohki, Thomas A; Schlafer, John; Mookerji, Bashkar; Kline, Jeffrey S; Pappas, David P

    2009-01-01

    The phenomenon of Coherent Population Trapping (CPT) of an atom (or solid state "artificial atom"), and the associated effect of Electromagnetically Induced Transparency (EIT), are clear demonstrations of quantum interference due to coherence in multi-level quantum systems. We report observation of CPT in a superconducting phase qubit by simultaneously driving two coherent transitions in a $\\Lambda$-type configuration, utilizing the three lowest lying levels of a local minimum of a phase qubit. We observe 58% suppression of excited state population under conditions of CPT resonance. We present data and matching theoretical simulations showing the development of CPT in time. Finally, we used the observed time dependence of the excited state population to characterize quantum dephasing times of the system.

  18. Sub-Doppler Laser Cooling of Thulium Atoms in a Magneto-optical Trap

    Sukachev, D; Chebakov, K; Akimov, A; Kanorsky, S; Kolachevsky, N; Sorokin, V

    2010-01-01

    We have experimentally studied sub-Doppler laser cooling in a magneto-optical trap for thulium atoms working at the wavelength of 410.6\\,nm. Without any dedicated molasses period of sub-Doppler cooling, the cloud of $3\\times 10^6$ atoms at the temperature of 25(5)\\,$\\mu$K was observed. The measured temperature is significantly lower than the Doppler limit of 240$\\mu$K for the cooling transition at 410.6\\,nm. High efficiency of the sub-Doppler cooling process is due to a near-degeneracy of the Land\\'e-$g$ factors of the lower $4f^{13}6s^{2}\\, (J\\,=\\,{7}/{2})$ and the upper $4f^{12}5d_{3/2}6s^{2}\\, (J\\,=\\,{9}/{2})$ cooling levels.}

  19. Sub-Doppler Cooling of Neutral Atoms in a Grating Magneto-Optical Trap

    Lee, J; Orozco, L A; Rolston, S L

    2013-01-01

    The grating magneto-optical trap (GMOT) requires only one beam and three planar diffraction gratings to form a cloud of cold atoms above the plane of the diffractors. Despite the complicated polarization arrangement, we demonstrate sub-Doppler cooling of 87Rb atoms to a temperature of 7.6(0.6) uK through a multi-stage, far-detuned GMOT in conjunction with optical molasses. A decomposition of the electric ?field into polarization components for this geometry does not yield a mapping onto standard sub-Doppler laser-cooling configurations. With numerical simulations, we find that the polarization composition of the GMOT optical field, which includes sigma?- and pi?-polarized light, does produce sub-Doppler temperatures.

  20. Trace analyses at the single particle level with Atom Trap Trace Analysis for 39Ar

    Atom optics has found many applications in different fields of physics. In the context of environmental physics the method of Atom Trap Trace Analysis (ATTA) has opened a new level of dating of water in the regime of very old water (millions of years) with 81Kr and recent water of the last 1000 years with 39Ar. The latter is the topic of this seminar revealing the challenges and experimental solutions to work with 39Ar concentrations in Ar as small as 1:1016. After the detailed discussion of the experimental techniques I will present the first results on dating of water with this method [1] and discuss the potential for samples as small as 1 liter. Being able to date such small samples we will open up a route for detecting the age distribution of the oceans. (author)

  1. Review of chip-scale atomic clocks based on coherent population trapping

    Research on chip-scale atomic clocks (CSACs) based on coherent population trapping (CPT) is reviewed. The background and the inspiration for the research are described, including the important schemes proposed to improve the CPT signal quality, the selection of atoms and buffer gases, and the development of micro-cell fabrication. With regard to the reliability, stability, and service life of the CSACs, the research regarding the sensitivity of the CPT resonance to temperature and laser power changes is also reviewed, as well as the CPT resonance's collision and light of frequency shifts. The first generation CSACs have already been developed but its characters are still far from our expectations. Our conclusion is that miniaturization and power reduction are the most important aspects calling for further research. (review)

  2. Performance of a prototype atomic clock based on lin||lin coherent population trapping resonances in Rb atomic vapor

    Mikhailov, Eugeniy E; Belcher, Nathan; Novikova, Irina

    2009-01-01

    We report on the performance of the first table-top prototype atomic clock based on coherent population trapping (CPT) resonances with parallel linearly polarized optical fields (lin||lin configuration). Our apparatus uses a vertical cavity surface emitting laser (VCSEL) tuned to the D1 line of 87Rb with current modulation at the 87Rb hyperfine frequency. We demonstrate cancellation of the first-order light shift by proper choice of rf modulation power, and further improve our prototype clock stability by optimizing the parameters of the microwave lock loop. Operating in these optimal conditions, we measured a short-term fractional frequency stability (Allan deviation) 2*10^{-11} tau^{-1/2} for observation times 1s

  3. Highly stable high power fiber laser system for optical trapping of ultracold atoms

    Full text: For our quantum gas experiments we simultaneously confine ultracold Rb and Cs atoms in an optical dipole trap. For that purpose the light of a commercially available, narrow-band, single mode 1064-nm solid-state laser is amplified in a home-built fiber amplifier using a Yb-doped large mode area (LMA) fiber. The fiber is pumped by a high-power 980-nm diode laser and yields an (amplified) narrow-band optical output of more than 30 W for an input seed power of about 1 W at 1064 nm. The performance of this fiber amplifier is presented in terms of slope efficiency, relative intensity noise (RIN), and long term stability. The light of the fiber laser is used for optical trapping of the quantum gas mixture in running wave and standing wave dipole traps. We present our progress towards the realization of a 3D optical lattice for the realization of strongly correlated quantum gas mixtures and for the study of quantum gas mixtures in low-dimensional geometry. (author)

  4. Production and trapping of radioactive atoms at the TRI\\muP facility

    Traykov, E; De, S; Dermois, O C; Huisman, L; Jungmann, K; Kruithof, W; Mol, A J; Onderwater, C J G; Rogachevskiy, A; Silva, M da Silva e; Sohani, M; Versolato, O; Willmann, L; Wilschut, H W

    2007-01-01

    The structures for the TRI$\\mu$P facility have been completed and commissioned. At the facility radioactive nuclides will be produced to study fundamental interactions and symmetries. An important feature is the possibility to trap radioactive atom in order to obtain and hold a pure substrate-free sample that will allow precision measurements. The TRI$\\mu$P facility consists of a chain of several separate units: A production target followed by a magnetic separator produces fast radioactive isotopes. The separator is commissioned and is operating. Various modes to produce radioactive particles have been tested for optimal production. A thermal ionizer stops the fast products and transports the nuclides as low energy singly charged ions into a radio frequency quadrupole cooler and buncher. This allows one to collect and transport the ions via a drift tube and a low energy beam line into a magneto-optical trap (MOT). The ions are neutralized in the MOT chamber and will be transported to a second trap for $\\beta$...

  5. Production and trapping of radioactive atoms at the TRI{mu}P facility

    Traykov, E. [Kernfysisch Versneller Instituut, University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands)], E-mail: traykov@kvi.nl; Dammalapati, U.; De, S.; Dermois, O.C.; Huisman, L.; Jungmann, K.; Kruithof, W.; Mol, A.J.; Onderwater, C.J.G.; Rogachevskiy, A.; Silva e Silva, M. da; Sohani, M.; Versolato, O.; Willmann, L.; Wilschut, H.W. [Kernfysisch Versneller Instituut, University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands)

    2008-10-15

    The structures for the TRI{mu}P facility have been completed and commissioned. At the facility radioactive nuclides are produced to study fundamental interactions and symmetries. An important feature is the possibility to trap radioactive atoms in order to obtain and hold a pure substrate-free sample for precision measurements. In the TRI{mu}P facility a production target is followed by a magnetic separator, where radioactive isotopes are produced in inverse reaction kinematics. Separation up to 99.95% could be achieved for {sup 21}Na. A novel transmitting thermal ionizing device was developed to stop the energetic isotopes. Some 50% of stopped {sup 21}Na could be extracted and transported as low energy singly charged ions into a radio frequency quadrupole cooler and buncher with 35% transmission efficiency. The ions are transported lossless via a drift tube and a low energy electrostatic beam line into the experimental setup. Such ions can be neutralized on hot metal foils and the resulting atoms can be stored in a magneto-optical trap. The functioning of that principle was demonstrated with stable Na extracted from the thermal ionizer, radioactive beams will follow next.

  6. Production and trapping of radioactive atoms at the TRIμP facility

    Traykov, E.; Dammalapati, U.; De, S.; Dermois, O. C.; Huisman, L.; Jungmann, K.; Kruithof, W.; Mol, A. J.; Onderwater, C. J. G.; Rogachevskiy, A.; da Silva e Silva, M.; Sohani, M.; Versolato, O.; Willmann, L.; Wilschut, H. W.

    2008-10-01

    The structures for the TRIμP facility have been completed and commissioned. At the facility radioactive nuclides are produced to study fundamental interactions and symmetries. An important feature is the possibility to trap radioactive atoms in order to obtain and hold a pure substrate-free sample for precision measurements. In the TRIμP facility a production target is followed by a magnetic separator, where radioactive isotopes are produced in inverse reaction kinematics. Separation up to 99.95% could be achieved for 21Na. A novel transmitting thermal ionizing device was developed to stop the energetic isotopes. Some 50% of stopped 21Na could be extracted and transported as low energy singly charged ions into a radio frequency quadrupole cooler and buncher with 35% transmission efficiency. The ions are transported lossless via a drift tube and a low energy electrostatic beam line into the experimental setup. Such ions can be neutralized on hot metal foils and the resulting atoms can be stored in a magneto-optical trap. The functioning of that principle was demonstrated with stable Na extracted from the thermal ionizer, radioactive beams will follow next.

  7. Exploring Ramsey-coherent population trapping atomic clock realized with pulsed microwave modulated laser

    A scheme for a Ramsey-coherent population trapping (CPT) atomic clock that eliminates the acousto-optic modulator (AOM) is proposed and experimentally studied. Driven by a periodically microwave modulated current, the vertical-cavity surface-emitting laser emits a continuous beam that switches between monochromatic and multichromatic modes. Ramsey-CPT interference has been studied with this mode-switching beam. In eliminating the AOM, which is used to generate pulsed laser in conventional Ramsey-CPT atomic clock, the physics package of the proposed scheme is virtually the same as that of a conventional compact CPT atomic clock, although the resource budget for the electronics will slightly increase as a microwave switch should be added. By evaluating and comparing experimentally recorded signals from the two Ramsey-CPT schemes, the short-term frequency stability of the proposed scheme was found to be 46% better than the scheme with AOM. The experimental results suggest that the implementation of a compact Ramsey-CPT atomic clock promises better frequency stability

  8. Lead determination at ng/mL level by flame atomic absorption spectrometry using a tantalum coated slotted quartz tube atom trap.

    Demirtaş, İlknur; Bakırdere, Sezgin; Ataman, O Yavuz

    2015-06-01

    Flame atomic absorption spectrometry (FAAS) still keeps its importance despite the relatively low sensitivity; because it is a simple and economical technique for determination of metals. In recent years, atom traps have been developed to increase the sensitivity of FAAS. Although the detection limit of FAAS is only at the level of µg/mL, with the use of atom traps it can reach to ng/mL. Slotted quartz tube (SQT) is one of the atom traps used to improve sensitivity. In atom trapping mode of SQT, analyte is trapped on-line in SQT for few minutes using ordinary sample aspiration, followed by the introduction of a small volume of organic solvent to effect the revolatilization and atomization of analyte species resulting in a transient signal. This system is economical, commercially available and easy to use. In this study, a sensitive analytical method was developed for the determination of lead with the help of SQT atom trapping flame atomization (SQT-AT-FAAS). 574 Fold sensitivity enhancement was obtained at a sample suction rate of 3.9 mL/min for 5.0 min trapping period with respect to FAAS. Organic solvent was selected as 40 µL of methyl isobutyl ketone (MIBK). To obtain a further sensitivity enhancement inner surface of SQT was coated with several transition metals. The best sensitivity enhancement, 1650 fold enhancement, was obtained by the Ta-coated SQT-AT-FAAS. In addition, chemical nature of Pb species trapped on quartz and Ta surface, and the chemical nature of Ta on quartz surface were investigated by X-ray photoelectron spectroscopy (XPS) and Raman Spectroscopy. Raman spectrometric results indicate that tantalum is coated on SQT surface in the form of Ta2O5. XPS studies revealed that the oxidation state of Pb in species trapped on both bare and Ta coated SQT surfaces is +2. For the accuracy check, the analyses of standard reference material were performed by use of SCP SCIENCE EnviroMAT Low (EU-L-2) and results for Pb were to be in good agreement with

  9. Radiative and collisional processes in translationally cold samples of hydrogen Rydberg atoms studied in an electrostatic trap

    Seiler, Ch; Agner, J. A.; Pillet, P.; Merkt, F.

    2016-05-01

    Supersonic beams of hydrogen atoms, prepared selectively in Rydberg–Stark states of principal quantum number n in the range between 25 and 35, have been deflected by {90}\\circ , decelerated and loaded into off-axis electric traps at initial densities of ≈ {10}6 atoms cm‑3 and translational temperatures of 150 mK. The ability to confine the atoms spatially was exploited to study their decay by radiative and collisional processes. The evolution of the population of trapped atoms was measured for several milliseconds in dependence of the principal quantum number of the initially prepared states, the initial Rydberg-atom density in the trap, and the temperature of the environment of the trap, which could be varied between 7.5 and 300 K using a cryorefrigerator. At room temperature, the population of trapped Rydberg atoms was found to decay faster than expected on the basis of their natural lifetimes, primarily because of absorption and emission stimulated by the thermal radiation field. At the lowest temperatures investigated experimentally, the decay was found to be multiexponential, with an initial rate scaling as {n}-4 and corresponding closely to the natural lifetimes of the initially prepared Rydberg–Stark states. The decay rate was found to continually decrease over time and to reach an almost n-independent rate of more than (1 ms)‑1 after 3 ms. To analyze the experimentally observed decay of the populations of trapped atoms, numerical simulations were performed which included all radiative processes, i.e., spontaneous emission as well as absorption and emission stimulated by the thermal radiation. These simulations, however, systematically underestimated the population of trapped atoms observed after several milliseconds by almost two orders of magnitude, although they reliably predicted the decay rates of the remaining atoms in the trap. The calculations revealed that the atoms that remain in the trap for the longest times have larger absolute values

  10. Optical trapping of ultracold dysprosium atoms: transition probabilities, dynamic dipole polarizabilities and van der Waals $C_6$ coefficients

    Li, Hui; Dulieu, Olivier; Nascimbene, Sylvain; Lepers, Maxence

    2016-01-01

    The efficiency of optical trapping of ultracold atoms depend on the atomic dynamic dipole polarizability governing the atom-field interaction. In this article, we have calculated the real and imaginary parts of the dynamic dipole polarizability of dysprosium in the ground and first excited level. Due to the high electronic angular momentum of those two states, the polarizabilities possess scalar, vector and tensor contributions that we have computed, on a wide range of trapping wavelengths, using the sum-over-state formula. Using the same formalism, we have also calculated the $C_6$ coefficients characterizing the van der Waals interaction between two dysprosium atoms in the two lowest levels. We have computed the energies of excited states and the transition probabilities appearing in the sums, using a combination of \\textit{ab initio} and least-square-fitting techniques provided by the Cowan codes and extended in our group. Regarding the real part of the polarizability, for field frequencies far from atomic...

  11. Solder self-assembled, surface micromachined MEMS for micromirror applications and atom trapping

    McCarthy, Brian

    Solder self-assembly can be used to expand the versatility of a commercial foundry, like MEMSCAP's PolyMUMPs process. These foundries are attractive for prototyping MEMS as they can offer consistent, low cost fabrication runs by sticking to a single process and integrating multiple customers on each wafer. However, this standardization limits the utility of the process for a given application. Solder self-assembly gives back some of this versatility and expands the envelope of surface micromachining capability in the form of a simple post-process step. Here it is used to create novel micromirrors and micromirror arrays as well as to delve into the field of ultracold atom optics where the utility of MEMS as an enabling technology for atom control is explored. Two types of torsional, electrostatic micromirrors are demonstrated, both of which can achieve +/-10° of rotation. The first is a novel out-of-plane micromirror that can be rotated to a desired angle from the substrate. This integrated, on-chip assembly allows much simpler packaging technology to be used for devices that require a laser beam to be steered off-chip. Planar micromirror arrays that use solder self-assembly to tailor the electrode gap height are also demonstrated. With these designs, no special fabrication techniques are required to achieve large gap heights, and micromirrors with a variety of gap heights can even be fabricated on the same chip. Finally, solder self-assembly is used to explore how complex micro-scale structures can be used to control ultracold atoms. For this study, a MEMS version of a magneto-optical trap, the basis for most ultracold atomic systems, is used to control Rb atoms. In doing so, it provides a path for the successful integration of a number of MEMS devices in these types of systems.

  12. Coherent population trapping resonances at lower atomic levels of Doppler broadened optical lines

    Şahin, E; Hamid, R; Çelik, M [National Metrology Institute of Turkey, Gebze, Kocaeli (Turkey); Özen, G [Istanbul Technical University, Faculty of Science and Letters, Engineering Physics Department Maslak, Istanbul (Turkey); Izmailov, A Ch [Institute of Physics, Azerbaijan National Academy of Sciences, H. Javid av. 33, Baku, Az-1143 (Azerbaijan)

    2014-11-30

    We have detected and analysed narrow high-contrast coherent population trapping (CPT) resonances, which are induced in absorption of a weak monochromatic probe light beam by counterpropagating two-frequency pump radiation in a cell with rarefied caesium vapour. The experimental investigations have been performed by the example of nonclosed three level Λ-systems formed by spectral components of the D{sub 2} line of caesium atoms. The applied method allows one to analyse features of the CPT phenomenon directly at a given low long-lived level of the selected Λ-system even in sufficiently complicated spectra of atomic gases with large Doppler broadening. We have established that CPT resonances in transmission of the probe beam exhibit not only a higher contrast but also a much lesser width in comparison with well- known CPT resonances in transmission of the corresponding two-frequency pump radiation. The results obtained can be used in selective photophysics, photochemistry and ultra-high resolution atomic (molecular) spectroscopy. (laser applications and other topics in quantum electronics)

  13. Collisional and radiative processes in adiabatic deceleration, deflection, and off-axis trapping of a Rydberg atom beam.

    Seiler, Ch; Hogan, S D; Schmutz, H; Agner, J A; Merkt, F

    2011-02-18

    A supersonic beam of Rydberg hydrogen atoms has been adiabatically deflected by 90°, decelerated to zero velocity in less than 25  μs, and loaded into an electric trap. The deflection has allowed the suppression of collisions with atoms in the trailing part of the gas pulse. The processes leading to trap losses, i.e., fluorescence to the ground state, and transitions and ionization induced by blackbody radiation have been monitored over several milliseconds and quantitatively analyzed. PMID:21405512

  14. Dispersive response of atoms trapped near the surface of an optical nanofiber with applications to QND measurement and spin squeezing

    Qi, Xiaodong; Jessen, Poul S; Deutsch, Ivan H

    2015-01-01

    We study the strong coupling between photons and atoms that can be achieved in an optical nanofiber geometry when the interaction is dispersive. While the Purcell enhancement factor for spontaneous emission into the guided mode does not reach the strong-coupling regime for individual atoms, one can obtain high cooperativity for ensembles of a few thousand atoms due to the tight confinement of the guided modes and constructive interference over the entire chain of trapped atoms. We calculate the dyadic Green's function, which determines the scattering of light by atoms in the presence of the fiber, and thus the phase shift and polarization rotation induced on the guided light by the trapped atoms. The Green's function is related to a full Heisenberg-Langevin treatment of the dispersive response of the quantized field to tensor polarizable atoms. We apply our formalism to quantum nondemolition (QND) measurement of the atoms via polarimetry. We study shot-noise-limited detection of atom number for atoms in a com...

  15. Two-step pulse observation for Raman-Ramsey coherent population trapping atomic clocks

    Yano, Yuichiro; Kajita, Masatoshi

    2014-01-01

    We propose a two-step pulse observation method to enhance frequency stability for coherent population trapping (CPT) atomic clocks. The proposed method is a Raman-Ramsey scheme with low light intensity at resonance observation, and provides a Ramsey-CPT resonance with both reduced frequency sensitivity to the light intensity and a high signal-to-noise ratio by reducing the repumping into a steady dark state. The resonance characteristics were calculated based on density matrix analysis of a $\\Lambda$-type three level system that was modeled on the $^{133}$Cs-D$_1$ line, and the characteristics were also measured using a vertical-cavity surface-emitting laser and a Cs vapor cell.

  16. Formation of molecular ions by radiative association of cold trapped atoms and ions

    Silva, Humberto Da; Aymar, Mireille; Dulieu, Olivier

    2015-01-01

    Radiative emission during cold collisions between trapped laser-cooled Rb atoms and alkaline-earth ions (Ca + , Sr + , Ba +) and Yb + are studied theoretically, using accurate effective-core-potential based quantum chemistry calculations of potential energy curves and transition dipole moments of the related molecular ions. Radiative association of molecular ions is predicted to occur for all systems with a cross section two to ten times larger than the radiative charge transfer one. Partial and total rate constants are also calculated and compared to available experiments. Narrow shape resonances are expected, which could be detectable at low temperature with an experimental resolution at the limit of the present standards. Vibrational distributions are also calculated, showing that the final molecular ions are not created in their ground state level.

  17. Formation of molecular ions by radiative association of cold trapped atoms and ions

    Dulieu, Olivier; da Silva, Humberto, Jr.; Aymar, Mireille; Raoult, Maurice

    2015-05-01

    Radiative emission during cold collisions between trapped laser-cooled Rb atoms and alkaline-earth ions (Ca+ , Sr+ , Ba+) and Yb+ are studied theoretically, using accurate effective-core-potential based quantum chemistry calculations of potential energy curves and transition dipole moments of the related molecular ions. Radiative association of molecular ions is predicted to occur for all systems with a cross section two to ten times larger than the radiative charge transfer one. Partial and total rate constants are also calculated and compared to available experiments. Narrow shape resonances are expected, which could be detectable at low temperature with an experimental resolution at the limit of the present standards. Vibrational distributions show that the final molecular ions are not created in their ground state level. Supported by the Marie-Curie ITN ``COMIQ: Cold Molecular Ions at the Quantum limit'' of the EU (#607491).

  18. Coherent population trapping on 87Rb atoms in small-size absorption cells with buffer gas

    Ermak, S. V.; Petrenko, M. V.; Semenov, V. V.

    2016-02-01

    Coherent population trapping (CPT) on 87Rb atoms in neon atmosphere has been studied in small-size glass absorption cells under conditions of pumping with narrow-band laser radiation at the D2 line of the main doublet. Parameters of the absorption signal have been measured in 3-mm-diameter cells at buffer gas (Ne) pressures varied within 200-400 Torr, cell temperatures within 65-120°C, and pumping radiation power densities within 30-400 μW/cm2. Optimum values of the buffer gas pressures, cell temperature, and pumping power are determined at which the short-term instability of the resonance line is at minimum. Orientational shifts of the CPT resonance signal in gas-filled cells and small-size cells with antirelaxation coating have been compared.

  19. Competition between Spin Echo and Spin Self-Rephasing in a Trapped Atom Interferometer

    Solaro, Cyrille; Combes, Frédéric; Lopez, Matthias; Alauze, Xavier; Fuchs, Jean-Noël; Piéchon, Frédéric; Santos, Franck Pereira dos

    2016-01-01

    We perform Ramsey interferometry on an ultracold 87Rb ensemble confined in an optical dipole trap. We use a $\\pi$-pulse set at the middle of the interferometer to restore the coherence of the spin ensemble by canceling out phase inhomogeneities and creating a spin echo in the contrast. However, for high atomic densities, we observe the opposite behavior: the $\\pi$-pulse accelerates the dephasing of the spin ensemble leading to a faster contrast decay of the interferometer. We understand this phenomenon as a competition between the spin-echo technique and an exchange-interaction driven spin self-rephasing mechanism based on the identical spin rotation effect (ISRE). Our experimental data is well reproduced by a numerical model.

  20. First observation of the strongly forbidden transition 1S0 - 3P0 in Strontium, for an atomic clock with trapped atoms

    This thesis reports the first results towards the realization of an optical clock using trapped strontium atoms. This set up would combine advantages of the different approaches commonly used to develop an atomic frequency standard. The first part describes the cold atoms source which is implemented. A magneto-optical trap operating on the 1S0-1P1 transition at 461 nm is loaded from an atomic beam decelerated by a Zeeman slower. The 461 nm laser is obtained by sum-frequency mixing in a potassium titanyl phosphate (KTP) crystal. The second part is devoted to the different stages developed to achieve the direct excitation of the 1S0-3P0 clock transition in 87Sr. This line has a theoretical natural width of 10-3 Hz. Before this detection, we obtained an estimate of the resonance frequency by measuring absolute frequencies of several allowed optical transitions. (author)

  1. Scheme for generating the singlet state of three atoms trapped in distant cavities coupled by optical fibers

    Wang, Dong-Yang [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Wen, Jing-Ji [College of Foundation Science, Harbin University of Commerce, Harbin, Heilongjiang 150028 (China); Bai, Cheng-Hua; Hu, Shi; Cui, Wen-Xue [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Wang, Hong-Fu, E-mail: hfwang@ybu.edu.cn [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Zhu, Ai-Dong [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China); Zhang, Shou, E-mail: szhang@ybu.edu.cn [Department of Physics, College of Science, Yanbian University, Yanji, Jilin 133002 (China)

    2015-09-15

    An effective scheme is proposed to generate the singlet state with three four-level atoms trapped in three distant cavities connected with each other by three optical fibers, respectively. After a series of appropriate atom–cavity interactions, which can be arbitrarily controlled via the selective pairing of Raman transitions and corresponding optical switches, a three-atom singlet state can be successfully generated. The influence of atomic spontaneous decay, photon leakage of cavities and optical fibers on the fidelity of the state is numerically simulated showing that the three-atom singlet state can be generated with high fidelity by choosing the experimental parameters appropriately.

  2. Design of a dual species atom interferometer for space

    Schuldt, Thilo; Schubert, Christian; Krutzik, Markus; Bote, Lluis Gesa; Gaaloul, Naceur; Hartwig, Jonas; Ahlers, Holger; Herr, Waldemar; Posso-Trujillo, Katerine; Rudolph, Jan; Seidel, Stephan; Wendrich, Thijs; Ertmer, Wolfgang; Herrmann, Sven; Kubelka-Lange, André; Milke, Alexander; Rievers, Benny; Rocco, Emanuele; Hinton, Andrew; Bongs, Kai; Oswald, Markus; Franz, Matthias; Hauth, Matthias; Peters, Achim; Bawamia, Ahmad; Wicht, Andreas; Battelier, Baptiste; Bertoldi, Andrea; Bouyer, Philippe; Landragin, Arnaud; Massonnet, Didier; Lévèque, Thomas; Wenzlawski, Andre; Hellmig, Ortwin; Windpassinger, Patrick; Sengstock, Klaus; von Klitzing, Wolf; Chaloner, Chris; Summers, David; Ireland, Philip; Mateos, Ignacio; Sopuerta, Carlos F.; Sorrentino, Fiodor; Tino, Guglielmo M.; Williams, Michael; Trenkel, Christian; Gerardi, Domenico; Chwalla, Michael; Burkhardt, Johannes; Johann, Ulrich; Heske, Astrid; Wille, Eric; Gehler, Martin; Cacciapuoti, Luigi; Gürlebeck, Norman; Braxmaier, Claus; Rasel, Ernst

    2015-06-01

    Atom interferometers have a multitude of proposed applications in space including precise measurements of the Earth's gravitational field, in navigation & ranging, and in fundamental physics such as tests of the weak equivalence principle (WEP) and gravitational wave detection. While atom interferometers are realized routinely in ground-based laboratories, current efforts aim at the development of a space compatible design optimized with respect to dimensions, weight, power consumption, mechanical robustness and radiation hardness. In this paper, we present a design of a high-sensitivity differential dual species 85Rb/87Rb atom interferometer for space, including physics package, laser system, electronics and software. The physics package comprises the atom source consisting of dispensers and a 2D magneto-optical trap (MOT), the science chamber with a 3D-MOT, a magnetic trap based on an atom chip and an optical dipole trap (ODT) used for Bose-Einstein condensate (BEC) creation and interferometry, the detection unit, the vacuum system for 10-11 mbar ultra-high vacuum generation, and the high-suppression factor magnetic shielding as well as the thermal control system. The laser system is based on a hybrid approach using fiber-based telecom components and high-power laser diode technology and includes all laser sources for 2D-MOT, 3D-MOT, ODT, interferometry and detection. Manipulation and switching of the laser beams is carried out on an optical bench using Zerodur bonding technology. The instrument consists of 9 units with an overall mass of 221 kg, an average power consumption of 608 W (814 W peak), and a volume of 470 liters which would well fit on a satellite to be launched with a Soyuz rocket, as system studies have shown.

  3. Performance of a prototype atomic clock based on lin parallel lin coherent population trapping resonances in Rb atomic vapor

    We report on the performance of the first table-top prototype atomic clock based on coherent population trapping (CPT) resonances with parallel linearly polarized optical fields (lin parallel lin configuration). Our apparatus uses a vertical-cavity surface-emitting laser (VCSEL) tuned to the D1 line of 87Rb with the current modulation at the 87Rb hyperfine frequency. We demonstrate cancellation of the first-order light shift by the proper choice of rf modulation power and further improve our prototype clock stability by optimizing the parameters of the microwave lock loop. Operating in these optimal conditions, we measured a short-term fractional frequency stability (Allan deviation) 2x10-11τ-1/2 for observation times 1 s≤τ≤20 s. This value is limited by large VCSEL phase noise and environmental temperature fluctuation. Further improvements in frequency stability should be possible with an apparatus designed as a dedicated lin parallel lin CPT resonance clock with environmental impacts minimized.

  4. Spectral narrowing of coherent population trapping resonance in laser-cooled and room-temperature atomic gas

    S Pradhan; S Mishra; R Behera; N Kawade; A K Das

    2014-02-01

    We have investigated coherent population trapping (CPT) in laser-cooled as well as room-temperature (with and without buffer gas) rubidium atoms. The characteristic broad signal profile emerging from the two-photon Raman resonance for room-temperature atomic vapour is consistent with the theoretical calculation incorporating associated thermal averaging. The spectral width of the dark resonance obtained with cold atoms is found to be broadened, compared to roomtemperature vapour cell, due to the feeble role played by thermal averaging, although the cold atomic sample significantly overcomes the limitation of the transit time broadening. An alternative way to improve transit time is to use a buffer gas, with which we demonstrate that the coherent population trapping signal width is reduced to < 540 Hz.

  5. Green method for ultrasensitive determination of Hg in natural waters by electrothermal-atomic absorption spectrometry following sono-induced cold vapor generation and 'in-atomizer trapping'

    Sono-induced cold vapor generation (SI-CVG) has been used for the first time in combination with a graphite furnace atomizer for determination of Hg in natural waters by electrothermal-atomic absorption spectrometry after in situ trapping onto a noble metal-pretreated platform (Pd, Pt or Rh) inserted into a graphite tube. The system allows 'in-atomizer trapping' of Hg without the use of conventional reduction reactions based on sodium borohydride or tin chloride in acid medium for cold vapor generation. The sono-induced reaction is accomplished by applying ultrasound irradiation to the sample solution containing Hg(II) in the presence of an organic compound such as formic acid. As this organic acid is partly degraded upon ultrasound irradiation to yield CO, CO2, H2 and H2O, the amount of lab wastes is minimized and a green methodology is achieved. For this purpose, experimental variables influencing the generation/trapping process are fully investigated. The limit of detection for a 10 min trapping time and 10 mL sample volume was 0.03 μg L-1 (Integrated absorbance) and the repeatability expressed as relative standard deviation was about 3%. Carbonates and chlorides at 100 mg L-1 level caused a signal depression by 20-30%. The enhanced trapping efficiency observed with the sono-induced cold vapor generation as compared with 'in-atomizer trapping' methods employing chemical vapor generation is discussed. A reaction pathway for SI-CVG is proposed on the basis of the current knowledge for synthesis of noble metal nanoparticles by ultrasound

  6. Spin structure of harmonically trapped one-dimensional atoms with spin-orbit coupling

    Guan, Q.; Blume, D.

    2015-08-01

    We introduce a theoretical approach to determine the spin structure of harmonically trapped atoms with two-body zero-range interactions subject to an equal mixture of Rashba and Dresselhaus spin-orbit coupling created through Raman coupling of atomic hyperfine states. The spin structure of bosonic and fermionic two-particle systems with finite and infinite two-body interaction strength g is calculated. Taking advantage of the fact that the N -boson and N -fermion systems with infinitely large coupling strength g are analytically solvable for vanishing spin-orbit coupling strength kso and vanishing Raman coupling strength Ω , we develop an effective spin model that is accurate to second order in Ω for any kso and infinite g . The three- and four-particle systems are considered explicitly. It is shown that the effective spin Hamiltonian, which contains a Heisenberg exchange term and an anisotropic Dzyaloshinskii-Moriya exchange term, describes the transitions that these systems undergo with the change of kso as a competition between independent spin dynamics and nearest-neighbor spin interactions.

  7. Nobel Prize in Physics 1997 "for development of methods to cool and trap atoms with laser light" : Steven Chu, Claude Cohen-Tannoudji and William D. Phillips

    1998-01-01

    Prof.S. Chu presents "the manipulation of atoms and bio-molecules by laser light" : a brief history of the laser cooling and trapping of atoms developed over the past 15 years will be presented. The cooling and trapping technology is already being applied in numerous areas of science and engineering. Applications to be discussed include atomic clocks, atom interferometers, as well as studies in polymer dynamics and protein motion.

  8. Atomic scale simulation of fission product trapping and migration in UO2+x and U3O8-z

    The paper discusses simulations, performed at atomic scale of fission product trapping and migration in UO2+x and U3O8-z. The solution and the migration of a range of volatile fission products including iodine, cesium, ruthenium in stoichiometric and nonstoichiometric UO2 and U3O8 are considered

  9. Using simple instrumentation to solve complex analytical problems: advanced AAS atomizers for volatile compounds and analyte trapping techniques

    Dědina, Jiří; de Moraes, D. P.; Dessuy, M. B.; Kratzer, Jan; Řezáčová, Olga; Svoboda, Milan; Matoušek, Tomáš; de Moraes Flores, E. M.; Vale, M. G. R.

    2010. s. 59. [Rio Symposium on Atomic Spectrometry /11./. 24.10.2010-29.10.2010, Mar del Plata] R&D Projects: GA ČR GA203/09/1783 Institutional research plan: CEZ:AV0Z40310501 Keywords : AAS * volatile compounds * analyte trapping techniques Subject RIV: CB - Analytical Chemistry, Separation http://www.11thriosymposium.com.ar/index.htm

  10. Atomic density and light intensity dependences of the Rb2 molecule formation rate constant in a magneto-optical trap

    In this paper, we report the measurement of molecular formation rate constant of Rb2 directly in a magneto-optical trap (MOT). The ground state molecules are detected by two-photon ionization, resonantly enhanced through the intermediate a3Σu+→23Πg molecular band. We have measured the rate constant as a function of atomic density to conclude that the molecules Rb2 are formed in the MOT by a photoassociation process caused by the trapping laser beams. We also measured the rate constant as a function of the trapping laser intensity. The results here presented are of importance to future experiments involving trapping of cold molecules

  11. Ramsey fringes in a Bose-Einstein condensate between atoms and molecules

    Kokkelmans, SJJMF Servaas; Holland, MJ

    2002-01-01

    In a recent experiment, a Feshbach scattering resonance was exploited to observe Ramsey fringes in a $^{85}$Rb Bose-Einstein condensate. The oscillation frequency corresponded to the binding energy of the molecular state. We show that the observations are remarkably consistent with predictions of a resonance field theory in which the fringes arise from oscillations between atoms and molecules.

  12. Modified oscillator approach to ultracold collisions in tight harmonic traps General model and application to metastable helium atoms

    Peach, G; Beams, T J; Peach, Gillian; Whittingham, Ian B; Beams, Timothy J

    2002-01-01

    A novel modified oscillator method of calculating energy eigenvalues for colliding ultracold atoms tightly confined in harmonic potentials is presented and applied to trapped spin-polarized metastable helium atoms. The perturbed harmonic oscillator problem is characterized by a long asymptotic region beyond the effective range of the interatomic potential, and a very efficient method for integrating inwards through this outer region is developed. The calculated eigenvalues for states with $l=0$ agree closely with those computed directly from the radial Schr\\"{o}dinger equation for the trapped atoms using a discrete variable method, and with those computed self-consistently from an energy-dependent effective scattering length. Finally, the self-consistent method is generalized to collisions with $l \

  13. Lifetime determination of the 5d$^{2}$~$^{3}$F$_{2}$ state in barium using trapped atoms

    De, S; Willmann, L

    2015-01-01

    Magneto-optically trapped atoms enable the determination of lifetimes of metastable states and higher lying excited states like the $\\rm{5d^{2}~^{3}F_{2}}$ state in barium. The state is efficiently populated by driving strong transitions from metastable states within the cooling cycle of the barium MOT. The lifetime is inferred from the increase of MOT fluorescence after the transfer of up to $30\\,\\%$ of the trapped atoms to this state. The radiative decay of the $\\rm{5d^{2}~^{3}F_{2}}$ state cascades to the cooling cycle of the MOT with a probability of $96.0(7)\\,\\%$ corresponding to a trap loss of $4.0(7)\\,\\%$ and its lifetime is determined to $\\rm{160(10)~\\mu s}$. This is in good agreement with the theoretically calculated lifetime of $\\rm{190~\\mu s}$ [J. Phys. B, {\\bf 40}, 227 (2007)]. The determined loss of $4.0(7)\\,\\%$ from the cooling cycle is compared with the theoretically calculated branching ratios. This measurement extends the efficacy of trapped atoms to measure lifetimes of higher, long-lived st...

  14. Quantitative atomic spectroscopy for primary thermometry

    Truong, Gar-Wing; May, Eric F.; Stace, Thomas M.; Luiten, Andre N.

    2010-01-01

    Quantitative spectroscopy has been used to measure accurately the Doppler-broadening of atomic transitions in $^{85}$Rb vapor. By using a conventional platinum resistance thermometer and the Doppler thermometry technique, we were able to determine $k_B$ with a relative uncertainty of $4.1\\times 10^{-4}$, and with a deviation of $2.7\\times 10^{-4}$ from the expected value. Our experiment, using an effusive vapour, departs significantly from other Doppler-broadened thermometry (DBT) techniques,...

  15. Capture of atoms and small particles in an optical trap formed by sequences of counter-propagating light pulses with a large area

    Romanenko, Victor I

    2012-01-01

    A new trap for atoms and small particles based on the interaction between an atom and the field of counter-propagating light pulses that are partially superposed in time has been proposed. A substantial difference from the known analogs consists in that the atom-field interaction is close to the adiabatic one, which allows a considerably higher momentum to be transferred to the atom within the same time interval and makes the trap smaller in size. It has been shown that, owing to the dependence of the light pressure force on the atom velocity, the atomic ensemble is cooled at its interaction with the field.

  16. Mesoporous Silica Nanoparticles as an Adsorbent for Preconcentration and Determination of Trace Amount of Nickel in Environmental Samples by Atom Trap Flame Atomic Absorption Spectrometry

    Shirkhanloo, H.; Falahnejad, M.; Zavvar Mousavi, H.

    2016-01-01

    A rapid enrichment method based on solid-phase extraction (SPE) has been established for preconcentration and separation of trace Ni(II) ions in water samples prior to their determination by atom trap flame atomic absorption spectrometry. A column filled with bulky NH2-UVM7 was used as the novel adsorbent. Under optimal conditions, the linear range, limit of detection (LOD), and preconcentration factor (PF) were 3-92 μg/L, 0.8 μg/L, and 100, respectively. The validity of the method was checked by the standard reference material.

  17. Arsenic speciation analysis by cryogenic trapping – hydride generation – atomic absorption spectrometry; Investigation of water vapour dryers

    Svoboda, Milan; Taurková, Petra; Matoušek, Tomáš; Rychlovský, P.; Dědina, Jiří

    Prague: Charles University in Prague, Faculty of Science, 2010 - (Nesměrák, K.), s. 15-18. (1). ISBN 978-80-7444-005-2. [International Students Conference "Modern Analytical Chemistry" /6./. Praha (CZ), 23.09.2010-24.09.2010] R&D Projects: GA ČR GA203/09/1783 Institutional research plan: CEZ:AV0Z40310501 Keywords : arsenic speciation * cryogenic trapping * atomic absorption spectrometry Subject RIV: CB - Analytical Chemistry, Separation

  18. Chaotic atomic population oscillations between two coupled Bose-Einstein condensates with time-dependent asymmetric trap potential

    Lee, Chaohong; Shi, Lei; Zhu, Xiwen; Gao, Kelin; Hai, Wenhua; Duan, Yiwu; Liu, Wing-Ki

    2000-01-01

    We have investigated the chaotic atomic population oscillations between two coupled Bose-Einstein condensates (BEC) with time-dependent asymmetric trap potential. In the perturbative regime, the population oscillations can be described by the Duffing equation, and the chaotic oscillations near the separatrix solution are analyzed. The sufficient-necessary conditions for stable oscillations depend on the physical parameters and initial conditions sensitively. The first-order necessary conditio...

  19. Generation of 99-mW continuous-wave 285-nm radiation for magneto-optical trapping of Mg atoms

    Madsen, Dorte Nørgaard; Yu, Ping; Balslev, Søren;

    2002-01-01

    We have developed a tunable intense narrow-band 285 nm light source based on frequency doubling of 570 nm light in BBO. At input powers of 840 mW (including 130 mW used for locking purposes) we generate 99 mW UV radiation with an intensity profile suitable for laser-cooling experiments. The light...... is used for laser cooling of neutral magnesium atoms in a magneto-optical trap (MOT). We capture about 5 x 10(6) atoms directly from a thermal beam and find that the major loss mechanism of the magnesium MOT is a near-resonant two-photon ionization process....

  20. Generation of 99-mW continuous-wave 285-nm radiation for magneto-optical trapping of Mg atoms

    Madsen, D. N; Yu, P.; Balslev, S.;

    2002-01-01

    We have developed a tunable intense narrow-band 285 nm light source based on frequency doubling of 570 nm light in BBO. At input powers of 840 mW (including 130 mW used for locking purposes) we generate 99 mW UV radiation with an intensity profile suitable for laser-cooling experiments. The light...... is used for laser cooling of neutral magnesium atoms in a magneto-optical trap (MOT). We capture about 5×106 atoms directly from a thermal beam and find that the major loss mechanism of the magnesium MOT is a near-resonant two-photon ionization process....

  1. An electrostatic glass actuator for ultrahigh vacuum: A rotating light trap for continuous beams of laser-cooled atoms.

    Füzesi, F; Jornod, A; Thomann, P; Plimmer, M D; Dudle, G; Moser, R; Sache, L; Bleuler, H

    2007-10-01

    This article describes the design, characterization, and performance of an electrostatic glass actuator adapted to an ultrahigh vacuum environment (10(-8) mbar). The three-phase rotary motor is used to drive a turbine that acts as a velocity-selective light trap for a slow continuous beam of laser-cooled atoms. This simple, compact, and nonmagnetic device should find applications in the realm of time and frequency metrology, as well as in other areas of atomic, molecular physics and elsewhere. PMID:17979408

  2. Laser Cooling and Trapping of Neutral Mercury Atoms Using an Optically-Pumped External-Cavity Semiconductor Laser

    Paul, Justin; Lytle, Christian; Jones, R. Jason

    2011-05-01

    The level structure of the Hg atom is similar to other alkaline earth-like atoms, offering the possibility to realize an extremely high quality resonance factor (Q) on the ``clock'' transition (1S0- 3P0) when confined in an optical lattice at the Stark-shift free wavelength. A key feature of the Hg system is the reduced uncertainty due to black-body induced Stark shifts, making it an interesting candidate as an optical frequency standard. One challenge to laser-cooling neutral Hg atoms is finding a reliable source for cooling on the 1S0-3 P1 transition at 253.7 nm. We employ an optically pumped semiconductor laser (OPSEL) operating at 1015 nm, whose frequency is quadrupled in two external-cavity doubling stages to generate over 120 mW at 253.7 nm. With this new laser source we have trapped Hg199 from a background vapor in a standard MOT. We trap up to 2 × 106 atoms with a 1/e2 radius of our MOT of ~310 microns, corresponding to a density of 1.28 × 1010 atoms/cm3. We report on the progress of our Hg system and plans for precision lattice-based spectroscopy of the clock transition. Support for this work is supported through the U.S. Air Force Office of Scientific Research (AFOSR) through grant no. FA9550-09-1-0563.

  3. Under-coordinated atoms induced local strain, quantum trap depression and valence charge polarization at W stepped surfaces

    We have explored the effects of atoms under-coordination on surface structure relaxation, binding energy shift of W stepped surfaces and valence charge polarization by the method of incorporating bond order-length-strength (BOLS) correlation mechanism into high-resolution X-ray photoluminescence spectra (XPS) measurements as well as density functional theory (DFT) calculations. Results show that the 4f7/2 energy levels of bulk, surface skin and step edge W atoms shift deeper from 2.17 to 2.69 eV with respect to that of the isolated W (28.91±0.01 eV) atoms, while the valence charge energy shift upper from inner to outer layer and from bulk to stepped edge. The surface bond contraction occurs around under-coordinated atoms after geometry relaxation calculation. Consistency among BOLS calculations, DFT calculation and experimental measurements clarifies that the surface bond contraction and consolidation due to the effects of under-coordination atoms induce potential trap depression, which provides perturbation to the Hamiltonian and hence contributes to the surface core level shift deeper, and that the surface valence charge are polarized by the densely trapped core-level electrons to upper energy.

  4. Magneto-optical trapping forces for atoms and molecules with complex level structures

    Laser cooling and magneto-optical trapping of molecules typically involves multiple transitions driven by several laser frequencies. We analyze how magneto-optical trapping forces depend on the angular momenta, Fl and Fu, and the g-factors, gl and gu, of the lower and upper states. When Fl>Fu the polarizations must be reversed relative to cases where Fu⩾Fl. The correct choice of circular polarization depends on the sign of gu but not on the sign of gl. If gu is zero there is no trapping force, and the trapping force is very weak whenever gu is small compared to gl, which it usually is when the cooling transition is the 2Σ to 2Π1/2 transition of a molecule. For some molecules, mixing of the excited 2Π1/2 state with a nearby 2Σ excited state can greatly increase gu, leading to stronger trapping forces. A strong trapping force can also be produced by rapidly and synchronously reversing both the magnetic field and the laser polarizations. We simulate a recent experiment on magneto-optical trapping of SrF molecules, and suggest that an alternative choice of laser beam polarizations will strengthen the trapping force. (paper)

  5. Sensitive determination of bismuth by flame atomic absorption spectrometry using atom trapping in a slotted quartz tube and revolatilization with organic solvent pulse

    Sensitivity of flame atomic absorption spectrometry (FAAS) for Bi determination was improved by slotted quartz tube (SQT) that was used also for atom trapping (AT). The trapped analyte was released by aspirating a small volume of organic solvent after a reasonable analyte collection time. Sensitivity was improved by 2.9 times by SQT-FAAS and 256 times by SQT-AT-FAAS with respect to FAAS. Optimum trapping period was found to be 6.0 min (36.0 mL of solution). Limit of detection (LOD) for SQT-AT-FAAS was found to be 1.6 ng mL−1. %RSD was calculated as 4.0% for five replicate measurements of 7.5 ng mL−1 Bi by SQT-AT-FAAS. Accuracy of the method developed was checked by analyzing a standard reference material of simulated fresh water (NIST 1643e) and result found was in good agreement with the certified one. The method can be applied in any laboratory equipped with a flame AA spectrometer. The consumption of time and sample volume is fairly low and application is simple and easy.

  6. Suppression of single cesium atom heating in a microscopic optical dipole trap for demonstration of an 852nm triggered single-photon source

    Liu, Bei; He, Jun; Wang, Junmin

    2016-01-01

    We investigate single cesium (Cs) atom heating owing to the momentum accumulation process induced by the resonant pulsed excitation in a microscopic optical dipole trap formed by a strongly focused 1064 nm laser beam. The heating depends on the trap frequency which restricts the maximum repetition rate of pulsed excitation. We experimentally verify the heating of a single atom and then demonstrate how to suppress it with an optimized pulsed excitation/cooling method. The typical trap lifetime of single Cs atom is extended from 108 +/- 6 us to 2536 +/- 31 ms, and the corresponding number of excitation increases from ~ 108 to ~ 360000. In applying this faster cooling method, we use the trapped single Cs atom as a triggered single-photon source at an excitation repetition rate of 10 MHz. The second-order intensity correlations of the emitted single photons are characterized by implementing Hanbury Brown and Twiss setup, and clear anti-bunching effect has been observed.

  7. Quantum phase gate through the dispersive atom–field interaction with atoms trapped in optical cavity QED

    Dong, Dong; Zhang, Yan-Lei; Zou, Chang-Ling, E-mail: clzou321@ustc.edu.cn; Zou, Xu-Bo, E-mail: xbz@ustc.edu.cn; Guo, Guang-Can

    2015-10-09

    We propose an experimental feasible scheme for implementing two-qubit quantum phase gate with atoms trapped in an optical cavity. The scheme is based on the dispersive interaction between the optical cavity mode and the three-level atoms in Λ configuration, which has been demonstrated in recent cavity-induced spin squeezing experiment (Leroux et al., 2010) [26]. We also discuss the influence of the cavity decay on the gate fidelity. It is shown that the fidelity of the phase gate is robust to the cavity decay and the high-fidelity quantum phase gate can be implemented with the current experimental technology. - Highlights: • A experimental feasible scheme for implementing two-qubit quantum phase gate. • Based on the dispersive interaction between the optical cavity mode and the symmetrically configurated three-level atoms. • Influence of the cavity decay on the gate fidelity is discussed.

  8. Capture of atoms and small particles in an optical trap formed by sequences of counter-propagating light pulses with a large area

    Romanenko, Victor I.; Yatsenko, Leonid P.

    2012-01-01

    A new trap for atoms and small particles based on the interaction between an atom and the field of counter-propagating light pulses that are partially superposed in time has been proposed. A substantial difference from the known analogs consists in that the atom-field interaction is close to the adiabatic one, which allows a considerably higher momentum to be transferred to the atom within the same time interval and makes the trap smaller in size. It has been shown that, owing to the dependen...

  9. The architecture of neutrophil extracellular traps investigated by atomic force microscopy

    Pires, Ricardo H.; Felix, Stephan B.; Delcea, Mihaela

    2016-07-01

    Neutrophils are immune cells that engage in a suicidal pathway leading to the release of partially decondensed chromatin, or neutrophil extracellular traps (NETs). NETs behave as a double edged sword; they can bind to pathogens thereby ensnaring them and limiting their spread during infection; however, they may bind to host circulating materials and trigger thrombotic events, and are associated with autoimmune disorders. Despite the fundamental role of NETs as part of an immune system response, there is currently a very poor understanding of how their nanoscale properties are reflected in their macroscopic impact. In this work, using a combination of fluorescence and atomic force microscopy, we show that NETs appear as a branching filament network that results in a substantially organized porous structure with openings with 0.03 +/- 0.04 μm2 on average and thus in the size range of small pathogens. Topological profiles typically up to 3 +/- 1 nm in height are compatible with a ``beads on a string'' model of nucleosome chromatin. Typical branch lengths of 153 +/- 103 nm appearing as rigid rods and height profiles of naked DNA in NETs of 1.2 +/- 0.5 nm are indicative of extensive DNA supercoiling throughout NETs. The presence of DNA duplexes could also be inferred from force spectroscopy and the occurrence of force plateaus that ranged from ~65 pN to 300 pN. Proteolytic digestion of NETs resulted in widespread disassembly of the network structure and considerable loss of mechanical properties. Our results suggest that the underlying structure of NETs is considerably organized and that part of its protein content plays an important role in maintaining its mesh architecture. We anticipate that NETs may work as microscopic mechanical sieves with elastic properties that stem from their DNA-protein composition, which is able to segregate particles also as a result of their size. Such a behavior may explain their participation in capturing pathogens and their association

  10. Chaotic atomic population oscillations between two coupled Bose-Einstein condensates with time-dependent asymmetric trap potential

    Lee, C; Zhu, X; Gao, K; Hai, W; Duan Yi Shi; Liu, W K; Lee, Chaohong; Shi, Lei; Zhu, Xiwen; Gao, Kelin; Hai, Wenhua; Duan, Yiwu; Liu, Wing-Ki

    2001-01-01

    We have investigated the chaotic atomic population oscillations between two coupled Bose-Einstein condensates (BEC) with time-dependent asymmetric trap potential. In the perturbative regime, the population oscillations can be described by the Duffing equation, and the chaotic oscillations near the separatrix solution are analyzed. The sufficient-necessary conditions for stable oscillations depend on the physical parameters and initial conditions sensitively. The first-order necessary condition indicates that the Melnikov function is equal to zero, so the stable oscillations are Melnikov chaotic. For the ordinary parameters and initial conditions, the chaotic dynamics is simulated with numerical calculation. If the damping is absent, with the increasing of the trap asymmetry, the regular oscillations become chaotic gradually, the corresponding stroboscopic Poincare sections (SPS) vary from a single island to more islands, and then the chaotic sea. For the completely chaotic oscillations, the long-term localiza...

  11. Atomic-layer deposited IrO2 nanodots for charge-trap flash-memory devices

    Charge-trap flash- (CTF) memory structures have been fabricated by employing IrO2 nanodots (NDs) grown by atomic-layer deposition. A band of isolated IrO2NDs of about 3 nm lying almost parallel to Si/SiO2 interface is confirmed by transmission electron microscopy and x-ray photoelectron spectroscopy. The memory device with IrO2NDs shows much larger capacitance-voltage (C-V) hysteresis and memory window compared with the control sample without IrO2NDs. After annealing at 800 deg. C for 20 min, the ND device shows almost no change in the width of C-V hysteresis and the ND distribution. These results indicate that the IrO2NDs embedded in SiO2 can be utilized as thermally stable, discrete charge traps, promising for metal oxide-ND-based CTF memory devices

  12. Simple Theoretical Models for Resonant Cold Atom Interactions

    Julienne, Paul S.; Gao, Bo

    2006-01-01

    Magnetically tunable scattering resonances have been used with great success for precise control of s-wave scattering lengths in ultracold atomic collisions. We describe relatively simple yet quite powerful analytic treatments of such resonances based on the analytic properties of the van der Waals long range potential. This theory can be used to characterize a number of properties of specific resonances that have been used successfully in various experiments with $^{87}$Rb, $^{85}$Rb, $^{40}...

  13. Novel search for heavy ν mixing from the β+ decay of K38m confined in an atom trap

    A new technique, full neutrino momentum reconstruction, is used to set limits on the admixture of heavy neutrinos into the electron neutrino. We measure coincidences between nuclear recoils and positrons from the beta decay of trapped radioactive atoms and deduce the neutrino momentum. A search for peaks in the reconstructed recoil time-of-flight spectrum as a function of positron energy is performed. The admixture upper limits range from 4x10-3 to 2x10-2 and are the best direct limits for neutrinos (as opposed to antineutrinos) for the mass region of 0.7 to 3.5 MeV

  14. Blue-detuned evanescent field surface traps for neutral atoms based on mode interference in ultra-thin optical fibres

    Sague, G.; Baade, A.; Rauschenbeutel, A.

    2008-01-01

    We present and analyze a novel concept for blue-detuned evanescent field surface traps for cold neutral atoms based on two-mode interference in ultra-thin optical fibres. When two or more transverse modes with the same frequency co-propagate in the fibre, their different phase velocities cause a stationary interference pattern to establish. Intensity minima of the evanescent field at any distance from the fibre surface can be created and an array of optical microtraps can thus be obtained in ...

  15. Compact field programmable gate array-based pulse-sequencer and radio-frequency generator for experiments with trapped atoms

    We present a compact field-programmable gate array (FPGA) based pulse sequencer and radio-frequency (RF) generator suitable for experiments with cold trapped ions and atoms. The unit is capable of outputting a pulse sequence with at least 32 transistor-transistor logic (TTL) channels with a timing resolution of 40 ns and contains a built-in 100 MHz frequency counter for counting electrical pulses from a photo-multiplier tube. There are 16 independent direct-digital-synthesizers RF sources with fast (rise-time of ∼60 ns) amplitude switching and sub-mHz frequency tuning from 0 to 800 MHz

  16. Compact field programmable gate array-based pulse-sequencer and radio-frequency generator for experiments with trapped atoms

    Pruttivarasin, Thaned, E-mail: thaned.pruttivarasin@riken.jp [Quantum Metrology Laboratory, RIKEN, Wako-shi, Saitama 351-0198 (Japan); Katori, Hidetoshi [Quantum Metrology Laboratory, RIKEN, Wako-shi, Saitama 351-0198 (Japan); Innovative Space-Time Project, ERATO, JST, Bunkyo-ku, Tokyo 113-8656 (Japan); Department of Applied Physics, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2015-11-15

    We present a compact field-programmable gate array (FPGA) based pulse sequencer and radio-frequency (RF) generator suitable for experiments with cold trapped ions and atoms. The unit is capable of outputting a pulse sequence with at least 32 transistor-transistor logic (TTL) channels with a timing resolution of 40 ns and contains a built-in 100 MHz frequency counter for counting electrical pulses from a photo-multiplier tube. There are 16 independent direct-digital-synthesizers RF sources with fast (rise-time of ∼60 ns) amplitude switching and sub-mHz frequency tuning from 0 to 800 MHz.

  17. Fast Non-destructive temperature measurement of two-electrons atoms in a magneto-optical trap

    Cristiani, Matteo; Valenzuela, Tristan; Gothe, Hannes; Eschner, Jürgen

    2010-01-01

    We extend the technique originally proposed by Honda et al.to measure the temperature of Ytterbium and alkine-earth atoms confined in a Magneto-Optical Trap (MOT). The method is based on the analysis of excitation spectra obtained by probing the 1S0->3P1 inter-combination line. Thanks to a careful analysis and modeling of the effects caused by the MOT light on the probe transition we overcome the resolution and precision limits encountered in previous works. Ground state light shift and Rabi ...

  18. TRI mu P - A new facility to investigate fundamental interactions with optically trapped radioactive atoms

    Jungmann, K

    2002-01-01

    At the Kernfysisch Versneller Instituut (KVI) in Groningen, NL, a new facility (TRImuP) is under development. It aims for producing, slowing down and trapping of radioactive isotopes in order to perform accurate measurements on fundamental symmetries and interactions. A spectrum of radioactive nucli

  19. Fast Non-destructive temperature measurement of two-electrons atoms in a magneto-optical trap

    Cristiani, Matteo; Gothe, Hannes; Eschner, Jürgen

    2010-01-01

    We extend the technique originally proposed by Honda et al.to measure the temperature of Ytterbium and alkine-earth atoms confined in a Magneto-Optical Trap (MOT). The method is based on the analysis of excitation spectra obtained by probing the 1S0->3P1 inter-combination line. Thanks to a careful analysis and modeling of the effects caused by the MOT light on the probe transition we overcome the resolution and precision limits encountered in previous works. Ground state light shift and Rabi broadening are measured and successfully compared with calculated values. This knowledge allows us to properly extract the Doppler contribution to the linewidth, thus obtaining a reliable measurement of the cloud temperature. We finally show how spectroscopy on free-falling atoms provides an alternative method to determine the sample temperature which resembles the standard time-of-flight technique.

  20. Investigations of the ground-state hyperfine atomic structure and beta decay measurement prospects of 21Na with improved laser trapping techniques

    This thesis describes an experiment in which a neutral atom laser trap loaded with radioactive 21Na was improved and then used for measurements. The sodium isotope (half-life=22 sec) is produced on line at the 88in cyclotron at Lawrence Berkeley National Laboratory. The author developed an effective magnesium oxide target system which is crucial to deliver a substantive beam of 21Na to the experiment. Efficient manipulation of the 21Na beam with lasers allowed 30,000 atoms to be contained in a magneto-optical trap. Using the cold trapped atoms, the author measured to high precision the hyperfine splitting of the atomic ground state of 21Na. She measured the 3S1/2(F=1,m=0)-3S1/2(F=2,m=0) atomic level splitting of 21Na to be 1,906,471,870±200 Hz. Additionally, she achieved initial detection of beta decay from the trap and evaluated the prospects of precision beta decay correlation studies with trapped atoms

  1. Investigations of the ground-state hyperfine atomic structure and beta decay measurement prospects of {sup 21}Na with improved laser trapping techniques

    Rowe, Mary A.

    1999-05-24

    This thesis describes an experiment in which a neutral atom laser trap loaded with radioactive {sup 21}Na was improved and then used for measurements. The sodium isotope (half-life=22 sec) is produced on line at the 88in cyclotron at Lawrence Berkeley National Laboratory. The author developed an effective magnesium oxide target system which is crucial to deliver a substantive beam of {sup 21}Na to the experiment. Efficient manipulation of the {sup 21}Na beam with lasers allowed 30,000 atoms to be contained in a magneto-optical trap. Using the cold trapped atoms, the author measured to high precision the hyperfine splitting of the atomic ground state of {sup 21}Na. She measured the 3S{sub 1/2}(F=1,m=0)-3S{sub 1/2}(F=2,m=0) atomic level splitting of {sup 21}Na to be 1,906,471,870{+-}200 Hz. Additionally, she achieved initial detection of beta decay from the trap and evaluated the prospects of precision beta decay correlation studies with trapped atoms.

  2. Trapping a single atom with a fraction of a photon using a photonic crystal nanocavity

    van Oosten, D.; Kuipers, L.

    2011-01-01

    We consider the interaction between a single rubidium atom and a photonic crystal nanocavity. Because of the ultrasmall mode volume of the nanocavity, an extremely strong coupling regime can be achieved in which the atom can shift the cavity resonance by many cavity linewidths. We show that this shi

  3. An atomic beam source for fast loading of a magneto-optical trap under high vacuum

    McDowall, P.D.; Hilliard, Andrew; Grünzweig, T.;

    2012-01-01

    We report on a directional atomic beam created using an alkali metal dispenser and a nozzle. By applying a high current (15 A) pulse to the dispenser at room temperature we can rapidly heat it to a temperature at which it starts dispensing, avoiding the need for preheating. The atomic beam produced...

  4. Atomic parity violation in heavy alkalis: detection by stimulated emission for cesium and traps for cold francium

    The present work deals with the recent advances of atomic spectroscopy experiments on cesium and francium, which aim at precise parity violation (PV) measurements in these atoms. Within the framework of a 'double-badged thesis', the candidate devoted himself on the one hand to the preliminary PV measurement (8% accuracy) of the present Cs experiment at the Kastler-Brossel laboratory in Paris and on the other hand to the preparation of a Fr radioactive atomic sample (production and trapping) at the LNL (INFN) in Italy. The two experiments are at very different stages. The measurements reported for cesium were actually made possible thanks to the work initiated in 1991, for the PV detection by stimulated emission. The Italian experiment is instead in a beginning stage: in order to probe the properties of francium, which is unstable, a number of atoms large enough has to be first produced and collected. The PV schemes which proved to be well suited for cesium are a solid starting point for the case of francium. (author)

  5. Atomic parity violation in heavy alkalis: detection by stimulated emission for cesium and traps for cold francium

    Sanguinetti, St

    2004-07-01

    The present work deals with the recent advances of atomic spectroscopy experiments on cesium and francium, which aim at precise parity violation (PV) measurements in these atoms. Within the framework of a 'double-badged thesis', the candidate devoted himself on the one hand to the preliminary PV measurement (8% accuracy) of the present Cs experiment at the Kastler-Brossel laboratory in Paris and on the other hand to the preparation of a Fr radioactive atomic sample (production and trapping) at the LNL (INFN) in Italy. The two experiments are at very different stages. The measurements reported for cesium were actually made possible thanks to the work initiated in 1991, for the PV detection by stimulated emission. The Italian experiment is instead in a beginning stage: in order to probe the properties of francium, which is unstable, a number of atoms large enough has to be first produced and collected. The PV schemes which proved to be well suited for cesium are a solid starting point for the case of francium. (author)

  6. Minimization of detection limits in arsenic speciation analysis by hydride generation - cryogenic trapping - atomic absorption spectrometry

    Svoboda, Milan; Matoušek, Tomáš; Stýblo, M.; Rychlovský, P.; Dědina, Jiří

    Xiamen: Xiamen University Press, 2007. s. 77. [Colloquium Spectroscopicum Internationale /35./. 23.09.2007-27.09.2007, Xiamen] R&D Projects: GA AV ČR IAA400310507 Grant ostatní: NIH-FIRCA(US) 1 R03 TW007057-01 Institutional research plan: CEZ:AV0Z40310501 Keywords : cryogenic trapping * arsenic speciation * hydride generation Subject RIV: CB - Analytical Chemistry, Separation

  7. Arsenic speciation analysis by hydride generation - cryogenic trapping - atomic absorption spectrometry

    Svoboda, Milan; Matoušek, Tomáš; Stýblo, M.; Rychlovský, P.; Dědina, Jiří

    Lednice: Spektroskopická společnost Jana Marka Marci, 2007. s. 80. ISBN 80-903732-2-4. [Spektroskopická konference /13./. 18.06.2007-21.06.2007, Lednice] R&D Projects: GA AV ČR IAA400310507 Grant ostatní: NIH-FIRCA(US) 1 R03 TW007057-01 Institutional research plan: CEZ:AV0Z40320502 Keywords : cryogenic trapping * arsenic speciation * hydride generation Subject RIV: CB - Analytical Chemistry, Separation

  8. Nobel Prize in Physics 1997 "for development of methods to cool and trap atoms with laser light" : Steven Chu, Claude Cohen-Tannoudji and William D. Phillips

    Audiovideo service

    1998-01-01

    Prof. C. Cohen-Tannoudji presents "manipulating atoms with light" . By using quasi-resonant exchanges of energy, linear and angular momentum between atoms and photons, it is possible to polarize atoms, to displace their energy levels and to control their position and their velocity. A few physical mechanisms allowing one to trap atoms and to cool them in the microKelvin, and even in the nanoKelvin range, will be described. Various possible applications of such ultracold atoms will be also reviewed.

  9. Critical temperature of Bose-Einstein condensation in trapped atomic Bose-Fermi mixtures

    We calculate the shift in the critical temperature of Bose-Einstein condensation for a dilute Bose-Fermi mixture confined by a harmonic potential, to lowest order in both the Bose-Bose and Bose-Fermi coupling constants. The relative importance of the effect on the critical temperature of the boson-boson and boson-fermion interactions is investigated as a function of the parameters of the mixture. The possible relevance of the shift of the transition temperature in current experiments on trapped Bose-Fermi mixtures is discussed. (letter to the editor)

  10. Critical temperature of Bose-Einstein condensation in trapped atomic Bose-Fermi mixtures

    Albus, A P [Institut fuer Physik, Universitaet Potsdam, D-14469 Potsdam (Germany); Giorgini, S [Dipartimento di Fisica, Universita di Trento, and Istituto Nazionale per la Fisica della Materia, I-38050 Povo (Italy); Illuminati, F [Dipartimento di Fisica, Universita di Salerno, and Istituto Nazionale per la Fisica della Materia, I-84081 Baronissi (Italy); Viverit, L [Dipartimento di Fisica, Universita di Trento, and Istituto Nazionale per la Fisica della Materia, I-38050 Povo (Italy)

    2002-12-14

    We calculate the shift in the critical temperature of Bose-Einstein condensation for a dilute Bose-Fermi mixture confined by a harmonic potential, to lowest order in both the Bose-Bose and Bose-Fermi coupling constants. The relative importance of the effect on the critical temperature of the boson-boson and boson-fermion interactions is investigated as a function of the parameters of the mixture. The possible relevance of the shift of the transition temperature in current experiments on trapped Bose-Fermi mixtures is discussed. (letter to the editor)

  11. Born-Oppenheimer description of two atoms in a combined oscillator and lattice trap

    Sørensen, Ole Søe; Mølmer, Klaus

    2012-01-01

    We analyze the quantum states of two identical bosons in a combined harmonic oscillator and periodic lattice trap in one spatial dimension. In the case of tight-binding and only nearest-neighbor tunneling, the equations of motion are conveniently represented in the momentum representation. We sho...... that in the case of strong attraction between the particles, the different time scales of relative and center-of-mass motions validate a separation of the problem similar to the Born-Oppenheimer approximation applied in the description of electronic and nuclear motions in molecules....

  12. Dispersive response of atoms trapped near the surface of an optical nanofiber with applications to quantum nondemolition measurement and spin squeezing

    Qi, Xiaodong; Baragiola, Ben Q.; Jessen, Poul S.; Deutsch, Ivan H.

    2016-02-01

    We study the strong coupling between photons and atoms that can be achieved in an optical nanofiber geometry when the interaction is dispersive. While the Purcell enhancement factor for spontaneous emission into the guided mode does not reach the strong-coupling regime for individual atoms, one can obtain high cooperativity for ensembles of a few thousand atoms due to the tight confinement of the guided modes and constructive interference over the entire chain of trapped atoms. We calculate the dyadic Green's function, which determines the scattering of light by atoms in the presence of the fiber, and thus the phase shift and polarization rotation induced on the guided light by the trapped atoms. The Green's function is related to a full Heisenberg-Langevin treatment of the dispersive response of the quantized field to tensor polarizable atoms. We apply our formalism to quantum nondemolition (QND) measurement of the atoms via polarimetry. We study shot-noise-limited detection of atom number for atoms in a completely mixed spin state and the squeezing of projection noise for atoms in clock states. Compared with squeezing of atomic ensembles in free space, we capitalize on unique features that arise in the nanofiber geometry including anisotropy of both the intensity and polarization of the guided modes. We use a first-principles stochastic master equation to model the squeezing as a function of time in the presence of decoherence due to optical pumping. We find a peak metrological squeezing of ˜5 dB is achievable with current technology for ˜2500 atoms trapped 180 nm from the surface of a nanofiber with radius a =225 nm.

  13. Coherent Population Trapping Resonances in Cs Atomic Vapor Layers of Micrometric Thickness

    A. Krasteva

    2011-01-01

    Full Text Available We report on a novel behavior of the electromagnetically induced absorption (EIA resonance observed on the D2 line of Cs for atoms confined in cells with micrometric thickness. With the enhancement of light intensity, the EIA resonance amplitude suffers from fast reduction, and even at very low intensity (W < 1 mW/cm2, resonance sign reversal takes place and electromagnetically induced transparency (EIT resonance is observed. Similar EIA resonance transformation to EIT one is not observed in conventional cm-size cells. A theoretical model is proposed to analyze the physical processes behind the EIA resonance sign reversal with light intensity. The model involves elastic interactions between Cs atoms as well as elastic interaction of atom micrometric-cell windows, both resulting in depolarization of excited state which can lead to the new observations. The effect of excited state depolarization is confirmed also by the fluorescence (absorption spectra measurement in micrometric cells with different thicknesses.

  14. Decay of a superfluid current of ultracold atoms in a toroidal trap

    Mathey, Amy C.; Clark, Charles W.; Mathey, L.

    2014-08-01

    Using a numerical implementation of the truncated Wigner approximation, we simulate the experiment reported by Ramanathan et al. in Phys. Rev. Lett. 106, 130401 (2011), 10.1103/PhysRevLett.106.130401, in which a Bose-Einstein condensate is created in a toroidal trap and set into rotation via a phase imprinting technique. A potential barrier is then placed in the trap to study the decay of the superflow. We find that the current decays via thermally activated phase slips, which can also be visualized as vortices crossing the barrier region in the radial direction. Adopting the notion of critical velocity used in the experiment, we determine it to be lower than the local speed of sound at the barrier, in contradiction to the predictions of the zero-temperature Gross-Pitaevskii equation. We map out the superfluid decay rate and critical velocity as a function of temperature and observe a strong dependence. Thermal fluctuations offer a partial explanation of the experimentally observed reduction of the critical velocity from the phonon velocity.

  15. Spin Diffusion in Trapped Clouds of Cold Atoms with Resonant Interactions

    Bruun, Georg Morten; Pethick, C. J.

    2011-01-01

    We show that puzzling recent experimental results on spin diffusion in a strongly interacting atomic gas may be understood in terms of the predicted spin diffusion coefficient for a generic strongly interacting system. Three important features play a central role: (a) Fick’s law for diffusion must...

  16. Radioactive ion beam transportation for the fundamental symmetry study with laser-trapped atoms

    Arikawa, Hiroshi; Ando, S.; Aoki, T.; Ezure, S.; Harada, K.; Hayamizu, T.; Inoue, T.; Ishikawa, T.; Itoh, M.; Kawamura, H.; Kato, K.; Kato, T.; Uchiyama, A.; Aoki, T.; Furukawa, T.; Hatakeyama, A.; Hatanaka, K.; Imai, K.; Murakami, T.; Nataraj, H. S.; Sato, T.; Shimizu, Y.; Wakasa, T.; Yoshida, H. P.; Sakemi, Y.

    2014-02-01

    The search for the violation of the fundamental symmetry in a radioactive atom is the promising candidate for precision tests of the standard model and its possible extensions. The subtle signal arising from the symmetry violation is enhanced in heavy atoms, such as a francium (Fr). To realize high precision measurements, a large amount of radioactive isotopes is required. The Fr is produced via a nuclear fusion reaction using a melted gold target with a 18O primary beam at Cyclotron and Radioisotope Center, Tohoku University. The maximum extraction efficiency of the Fr ion was achieved at approximately 35%. The beam line consists of an electrostatic deflector, three electrostatic quadrupole triplets to the measurement area at 10 m away from the reaction point, and several beam diagnosis systems. We optimized parameters of the beam line.

  17. Ion-neutral chemistry at ultralow energies: Dynamics of reactive collisions between laser-cooled Ca^+ ions and Rb atoms in an ion-atom hybrid trap

    Hall, Felix H J; Hegi, Gregor; Raoult, Maurice; Aymar, Mireille; Dulieu, Olivier; Willitsch, Stefan

    2013-01-01

    Cold chemical reactions between laser-cooled Ca^+ ions and Rb atoms were studied in an ion-atom hybrid trap. Reaction rate constants were determined in the range of collision energies /k_B = 20 mK-20 K. The lowest energies were achieved in experiments using single localized Ca^+ ions. Product branching ratios were studied using resonant-excitation mass spectrometry. The dynamics of the reactive processes in this system (non-radiative and radiative charge transfer as well as radiative association leading to the formation of CaRb^+ molecular ions) have been analyzed using high-level quantum-chemical calculations of the potential energy curves of CaRb^+ and quantum-scattering calculations for the radiative channels. For the present low-energy scattering experiments, it is shown that the energy dependence of the reaction rate constants is governed by long-range interactions in line with the classical Langevin model, but their magnitude is determined by short-range non-adiabatic and radiative couplings which only ...

  18. Electrochemical selenium hydride generation with in situ trapping in graphite tube atomizers

    A manifold coupling continuous electrolytic hydride generation of volatile hydrides with atomization in graphite tube atomizers after in situ collection was used for Se(IV) determination. Laboratory-made thin-layer flow-through cells with lead wire (cell I) and granular lead (cell II) as the cathode material were used as the electrolytic generators of volatile selenium hydride. The automatic sampling equipment of the graphite atomizer, with an untreated fused silica capillary, was used both for the introduction of volatile hydride into the atomizer and for pretreatment of the graphite furnace surface with a palladium modifier. The influence of the experimental parameters on the analytical signal was studied and optimum conditions for selenium determination were found. The optimum experimental parameters for hydride generation were: catholyte (1 mol l-1 HCl)/anolyte (2 mol l-1 H2SO4) flow rate of 2.0 ml min-1; applied generation current of 1.2 A (cell I) and 0.8 A (cell II); and carrier gas flow rate of 40 (cell I) and 70 ml min-1 (cell II). The hydride generated was collected in the graphite tube (pre-treated with 5 μg of Pd reduced at 800 deg. C) at a temperature of 400 deg. C for 30 s. The overall efficiency of H2Se electrochemical generation, transport and collection was 71±7% for cell I and 80±5% for cell II. The results for electrochemical generation of H2Se (cell II) (absolute limit of detection 50 pg, 3σ criterion) were compared with the original generation of H2Se using NaBH4 as a reduction agent (absolute limit of detection 30 pg) and with conventional liquid sampling. The repeatability at the 1.0 ng ml-1 level was better than 2.4% (relative standard deviation) for electrochemical hydride generation and better than 2.8% for chemical hydride generation

  19. Rabi-Josephson oscillations and self-trapped dynamics in atomic junctions with two bosonic species

    Mazzarella, G.; Malomed, B.; Salasnich, L.; Salerno, M.; Toigo, F.

    2010-01-01

    We investigate the dynamics of two-component Bose-Einstein condensates (BECs), composed of atoms in two distinct hyperfine states, which are linearly coupled by two-photon Raman transitions. The condensate is loaded into a double-well potential (DWP). A variety of dynamical behaviors, ranging from regular Josephson oscillations, to mixed Rabi-Josephson oscillations and to regimes featuring an increasing complexity, are described in terms of a reduced Hamiltonian system with four degrees of fr...

  20. Interplay of Coexisting Odd-Order Wave Mixings in a Five-Level Atomic System

    SONG Yue; HUO Shu-Li; LI Pei-Ying; SANG Su-Ling; WANG Zhi-Guo; ZHANG Yan-Peng

    2011-01-01

    @@ We experimentally investigate the interplay between two coexisting six-wave mixing (SWM) signals and the interference between coexisting four-wave mixing (FWM) and SWM signals in a five-level atomic system of85 Rb.When two electromagnetically induced transparency windows gradually overlap in frequency, the competition between these two SWM signals arises.Moreover, we report the experimental result which shows that the temporal interference with femtosecond time scales between FWM and SWM signals.%We experimentally investigate the interplay between two coexisting six-wave mixing (SWM) signals and the interference between coexisting four-wave mixing (FWM) and SWM signals in a five-level atomic system of 85 Rb.When two electromagnetically induced transparency windows gradually overlap in frequency, the competition between these two SWM signals arises.Moreover, we report the experimental result which shows that the temporal interference with femtosecond time scales between FWM and SWM signals.

  1. Internal Josephson-like tunnelling in two-component Bose-Einstein condensates affected by sign of the atomic interaction and external trapping potential

    Xiong Bo; Liu Xun-Xu

    2007-01-01

    This paper studies the Josephson-like tunnelling in two-component Bose-Einstein condensates coupled with microwave field, which is in respond to various attractive and repulsive atomic interaction under the various aspect ratio of trapping potential. It is very interesting to find that the dynamic of Josephson-like tunnelling can be controlled from fast damped oscillations to nondamped oscillation, and relative number of atoms changes from asymmetric occupation to symmetric occupation correspondingly.

  2. Improvement of the signal-to-noise ratio of laser-induced-fluorescence photon-counting signals of single-atoms magneto-optical trap

    Employing grating extended-cavity diode lasers as the cooling/trapping and repumping lasers for preparing and manipulating single atoms, we have implemented a large-magnetic-gradient caesium magneto-optical trap (MOT). To detect and evaluate single caesium atoms trapped in MOT, laser-induced-fluorescence (LIF) photons of trapped atoms driven by MOT lasers are collected and counted by an avalanched photodiode worked in photon-counting mode. The dependences of LIF photon-counting signals of single atoms on a cooling laser's intensity, frequency detuning and frequency fluctuation are analysed and investigated. Remarkable improvement of the signal-to-noise ratio of LIF photon-counting signals is achieved by optimizing the cooling laser's intensity and frequency detuning and using the modulation-free polarization spectroscopic technique with feedback to both the slow channel (piezoelectric transducer channel with typical bandwidth of ∼2 kHz in the grating extended cavity) and the fast channel (current modulation channel with typical bandwidth of ∼200 kHz in the current driver).

  3. Precision Gravity Tests with Atom Interferometry in Space

    Tino, G.M.; Sorrentino, F. [Dipartimento di Fisica e Astronomia and LENS, Università di Firenze, INFN Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); Aguilera, D. [Institute of Space Systems, German Aerospace Center, Robert-Hooke-Strasse 7, 28359 Bremen (Germany); Battelier, B.; Bertoldi, A. [Laboratoire Photonique, Numérique et Nanosciences, LP2N - UMR5298 - IOGS - CNRS Université Bordeaux 1, Bâtiment A30 351 cours de la Libération F-33405 TALENCE Cedex France (France); Bodart, Q. [Dipartimento di Fisica e Astronomia and LENS, Università di Firenze, INFN Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino (Italy); Bongs, K. [Midlands Ultracold Atom Research Centre School of Physics and Astronomy University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Bouyer, P. [Laboratoire Photonique, Numérique et Nanosciences, LP2N - UMR5298 - IOGS - CNRS Université Bordeaux 1, Bâtiment A30 351 cours de la Libération F-33405 TALENCE Cedex France (France); Braxmaier, C. [Institute of Space Systems, German Aerospace Center, Robert-Hooke-Strasse 7, 28359 Bremen (Germany); Cacciapuoti, L. [European Space Agency, Research and Scientific Support Department, Keplerlaan 1, 2201 AZ Noordwijk (Netherlands); Gaaloul, N. [Institute of Quantum Optics, Leibniz Universitaet Hannover, Welfengarten 1, D 30167 Hannover (Germany); Gürlebeck, N. [University of Bremen, Centre of Applied Space Technology and Microgravity (ZARM), Am Fallturm, D - 29359 Bremen (Germany); Hauth, M. [Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin (Germany); and others

    2013-10-15

    Atom interferometry provides extremely sensitive and accurate tools for the measurement of inertial forces. Operation of atom interferometers in microgravity is expected to enhance the performance of such sensors. This paper presents two possible implementations of a dual {sup 85}Rb-{sup 87}Rb atom interferometer to perform differential gravity measurements in space, with the primary goal to test the Weak Equivalence Principle. The proposed scheme is in the framework of two projects of the European Space Agency, namely Q-WEP and STE-QUEST. The paper describes the baseline experimental configuration, and discusses the technology readiness, noise and error budget for the two proposed experiments.

  4. Precision Gravity Tests with Atom Interferometry in Space

    Atom interferometry provides extremely sensitive and accurate tools for the measurement of inertial forces. Operation of atom interferometers in microgravity is expected to enhance the performance of such sensors. This paper presents two possible implementations of a dual 85Rb-87Rb atom interferometer to perform differential gravity measurements in space, with the primary goal to test the Weak Equivalence Principle. The proposed scheme is in the framework of two projects of the European Space Agency, namely Q-WEP and STE-QUEST. The paper describes the baseline experimental configuration, and discusses the technology readiness, noise and error budget for the two proposed experiments

  5. Laser frequency locking with 46 GHz offset using an electro-optic modulator for magneto-optical trapping of francium atoms

    Harada, K; Ezure, S; Kato, K; Hayamizu, T; Kawamura, H; Inoue, T; Arikawa, H; Ishikawa, T; Aoki, T; Uchiyama, A; Sakamoto, K; Ito, S; Itoh, M; Ando, S; Hatakeyama, A; Hatanaka, K; Imai, K; Murakami, T; Nataraj, H S; Shimizu, Y; Sato, T; Wakasa, T; Yoshida, H P; Sakemi, Y

    2016-01-01

    We demonstrated a frequency offset locking between two laser sources using a waveguide-type electro-optic modulator (EOM) with 10th-order sidebands for magneto-optical trapping of Fr atoms. The frequency locking error signal was successfully obtained by performing delayed self-homodyne detection of the beat signal between the repumping frequency and the 10th-order sideband component of the trapping light. Sweeping the trapping-light and repumping-light frequencies with keeping its frequency difference of 46 GHz was confirmed over 1 GHz by monitoring the Doppler absorption profile of I2. This technique enables us to search for a resonance frequency of magneto-optical trapping of Fr.

  6. Accurate characterization and understanding of interface trap density trends between atomic layer deposited dielectrics and AlGaN/GaN with bonding constraint theory

    Many dielectrics have been proposed for the gate stack or passivation of AlGaN/GaN based metal oxide semiconductor heterojunction field effect transistors, to reduce gate leakage and current collapse, both for power and RF applications. Atomic Layer Deposition (ALD) is preferred for dielectric deposition as it provides uniform, conformal, and high quality films with precise monolayer control of film thickness. Identification of the optimum ALD dielectric for the gate stack or passivation requires a critical investigation of traps created at the dielectric/AlGaN interface. In this work, a pulsed-IV traps characterization method has been used for accurate characterization of interface traps with a variety of ALD dielectrics. High-k dielectrics (HfO2, HfAlO, and Al2O3) are found to host a high density of interface traps with AlGaN. In contrast, ALD SiO2 shows the lowest interface trap density (<2 × 1012 cm−2) after annealing above 600 °C in N2 for 60 s. The trend in observed trap densities is subsequently explained with bonding constraint theory, which predicts a high density of interface traps due to a higher coordination state and bond strain in high-k dielectrics

  7. Rydberg-induced optical nonlinearities from a cold atomic ensemble trapped inside a cavity

    Boddeda, R.; Usmani, I.; Bimbard, E.; Grankin, A.; Ourjoumtsev, A.; Brion, E.; Grangier, P.

    2016-04-01

    We experimentally characterize the optical nonlinear response of a cold atomic medium placed inside an optical cavity, and excited to Rydberg states. The excitation to S and D Rydberg levels is carried out via a two-photon transition in an electromagnetically induced transparency configuration, with a weak (red) probe beam on the lower transition, and a strong (blue) coupling beam on the upper transition. The observed optical nonlinearities induced by S states for the probe beam can be explained using a semi-classical model with van der Waals’ interactions. For the D states, it appears necessary to take into account a dynamical decay of Rydberg excitations into a long-lived dark state. We show that the measured nonlinearities can be explained by using a Rydberg bubble model with a dynamical decay.

  8. Rydberg-induced optical nonlinearities from a cold atomic ensemble trapped inside a cavity

    Boddeda, Rajiv; Bimbard, Erwan; Grankin, Andrey; Ourjoumtsev, Alexei; Brion, Etienne; Grangier, Philippe

    2015-01-01

    We experimentally characterize the optical nonlinear response of a cold atomic medium placed inside an optical cavity, and excited to Rydberg states. The excitation to S and D Rydberg levels is carried out via a two-photon transition in an EIT (electromagnetically induced transparency) configuration, with a weak (red) probe beam on the lower transition, and a strong (blue) coupling beam on the upper transition. The observed optical nonlinearities induced by S states for the probe beam can be explained using a semi-classical model with van der Waals' interactions. For the D states, it appears necessary to take into account a dynamical decay of Rydberg excitations into a long-lived dark state. We show that the measured nonlinearities can be explained by using a Rydberg bubble model with a dynamical decay.

  9. Application of potential harmonic expansion method to BEC: Thermodynamic properties of trapped 23Na atoms

    Anasuya Kundu; Barnali Chakrabarti; Tapan Kumar Das

    2005-07-01

    We adopt the potential harmonics expansion method for an ab initio solution of the many-body system in a Bose condensate containing interacting bosons. Unlike commonly adopted mean-field theories, our method is capable of handling two-body correlation properly. We disregard three- and higher-body correlations. This simplification is ideally suited to dilute Bose Einstein condensates, whose number density is required to be so small that the interparticle separation is much larger than the range of two-body interaction to avoid three- and higher-body collisions, leading to the formation of molecules and consequent instability of the condensate. In our method we can incorporate realistic finite range interactions. We calculate energies of low-lying states of a condensate containing 23Na atoms and some thermodynamical properties of the condensate.

  10. Radiation trapping and L\\'{e}vy flights in atomic vapours: an introductory review

    Chevrollier, Martine

    2013-01-01

    Multiple scattering is a process in which a particle is repeatedly deflected by other particles. In an overwhelming majority of cases, the ensuing random walk can successfully be described through Gaussian, or normal, statistics. However, like a (growing) number of other apparently inofensive systems, diffusion of light in dilute atomic vapours eludes this familiar interpretation, exhibiting a superdiffusive behavior. As opposed to normal diffusion, whereby the particle executes steps in random directions but with lengths slightly varying around an average value (like a drunkard whose next move is unpredictable but certain to within a few tens of centimeters), superdiffusion is characterized by sudden abnormally long steps (L\\'{e}vy flights) interrupting sequences of apparently regular jumps which, although very rare, determine the whole dynamics of the system. The formal statistics tools to describe superdiffusion already exist and rely on stable, well understood distributions. As scientists become aware of,...

  11. Deflection of a Λ-type three-level atom by a light field: a mechanical demonstration of the coherent population trapping effect

    We consider the deflection of a three-level atom of Λ-type interacting with a light field of two coherent laser beams. We employ the dressed state formalism, which is suitable for large Rabi frequencies and/or large detunings. A full study of the interaction and relaxation processes is performed. We show that a beam of atoms is split into three beams once it crosses the light field. This is a three-state version of the well-known optical Stern-Gerlach effect, which has been theoretically studied and experimentally demonstrated for two-level atoms. Under coherent population trapping conditions, the splitting of the beam becomes twofold. This gives us, in principle, the opportunity of a mechanical demonstration of the coherent population trapping effect. (paper)

  12. Generalized gradient expansion for inhomogeneous dynamical mean-field theory: Application to ultracold atoms in a harmonic trap

    Freericks, J. K.; Han, Shuyang; Mikelsons, Karlis; Krishnamurthy, H. R.

    2016-08-01

    We develop a generalized gradient expansion of the inhomogeneous dynamical mean-field theory method for determining properties of ultracold atoms in a trap. This approach goes beyond the well-known local density approximation and at higher temperatures, in the normal phase, it shows why the local density approximation works so well, since the local density and generalized gradient approximations are essentially indistinguishable from each other (and from the exact solution within full inhomogeneous dynamical mean-field theory). But because the generalized gradient expansion only involves nearest-neighbor corrections, it does not work as well at low temperatures, when the systems enter into ordered phases. This is primarily due to the problem that ordered phases often satisfy some global constraints, which determine the spatial ordering pattern, and the local density and generalized gradient approximations are not able to impose those kinds of constraints; they also overestimate the tendency to order. The theory is applied to phase separation of different mass fermionic mixtures represented by the Falicov-Kimball model and to determining the entropy per particle of a fermionic system represented by the Hubbard model. The generalized gradient approximation is a useful diagnostic for the accuracy of the local density approximation—when both methods agree, they are likely accurate, when they disagree, neither is likely to be correct.

  13. Measurement of the electron shake-off in the β-decay of laser-trapped 6He atoms

    Hong, Ran; Bagdasarova, Yelena; Garcia, Alejandro; Storm, Derek; Sternberg, Matthew; Swanson, Erik; Wauters, Frederik; Zumwalt, David; Bailey, Kevin; Leredde, Arnaud; Mueller, Peter; O'Connor, Thomas; Flechard, Xavier; Liennard, Etienne; Knecht, Andreas; Naviliat-Cuncic, Oscar

    2016-03-01

    Electron shake-off is an important process in many high precision nuclear β-decay measurements searching for physics beyond the standard model. 6He being one of the lightest β-decaying isotopes, has a simple atomic structure. Thus, it is well suited for testing calculations of shake-off effects. Shake-off probabilities from the 23S1 and 23P2 initial states of laser trapped 6He matter for the on-going beta-neutrino correlation study at the University of Washington. These probabilities are obtained by analyzing the time-of-flight distribution of the recoil ions detected in coincidence with the beta particles. A β-neutrino correlation independent analysis approach was developed. The measured upper limit of the double shake-off probability is 2 ×10-4 at 90% confidence level. This result is ~100 times lower than the most recent calculation by Schulhoff and Drake. This work is supported by DOE, Office of Nuclear Physics, under Contract Nos. DE-AC02-06CH11357 and DE-FG02-97ER41020.

  14. Automated Sampling and Extraction of Krypton from Small Air Samples for Kr-85 Measurement Using Atom Trap Trace Analysis

    Atom-Trap-Trace-Analysis (ATTA) provides the capability of measuring the Krypton-85 concentration in microlitre amounts of krypton extracted from air samples of about 1 litre. This sample size is sufficiently small to allow for a range of applications, including on-site spot sampling and continuous sampling over periods of several hours. All samples can be easily handled and transported to an off-site laboratory for ATTA measurement, or stored and analyzed on demand. Bayesian sampling methodologies can be applied by blending samples for bulk measurement and performing in-depth analysis as required. Prerequisite for measurement is the extraction of a pure krypton fraction from the sample. This paper introduces an extraction unit able to isolate the krypton in small ambient air samples with high speed, high efficiency and in a fully automated manner using a combination of cryogenic distillation and gas chromatography. Air samples are collected using an automated smart sampler developed in-house to achieve a constant sampling rate over adjustable time periods ranging from 5 minutes to 3 hours per sample. The smart sampler can be deployed in the field and operate on battery for one week to take up to 60 air samples. This high flexibility of sampling and the fast, robust sample preparation are a valuable tool for research and the application of Kr-85 measurements to novel Safeguards procedures. (author)

  15. Highly sensitive and interference-free determination of bismuth in environmental samples by electrothermal vaporization atomic fluorescence spectrometry after hydride trapping on iridium-coated tungsten coil

    Bismuthine was on-line trapped on tungsten coil and subsequently electrothermally vaporized for the determination by atomic fluorescence spectrometry (AFS). Several noble metals, including Pd, Rh, Pt, and Ir, were explored as permanent chemical modifier for tungsten coil on-line trapping. Investigation showed that Ir gave the best performance, in which bismuthine was on-line trapped on Ir-coated tungsten coil at 560 oC, and then released at 1550 oC for subsequent transfer to AFS by a mixture of Ar and H2. Under optimum instrumental conditions, the trapping efficiency was found to be 73 ± 3%. With 120 s (12 mL sample volume) trapping time, a limit of detection (LOD) of 4 ng L-1 was obtained, compared to conventional hydride generation AFS (0.09 μg L-1); the LOD can be lowered down to 1 ng L-1 by increasing the trapping time to 480 s. The LOD was found to be better or at least comparable to literature levels involving on-line trapping and some other sophisticated instrumental methods such as ICP-MS and GF-AAS. A comprehensive interference study involving conventional hydride-forming elements and some transition metals was carried out, and the result showed that the gas phase interference from other hydride-forming elements was largely reduced, thanks to the use of on-line tungsten coil trapping. Finally, the proposed method was applied to the determination of bismuth in several biological and environmental standard reference materials, and a t-test shows that the analytical results by the proposed method have no significant difference from the certified values at the confidence level of 95%

  16. Direct comparison between a two-dimensional magneto-optical trap and a Zeeman slower as sources of cold sodium atoms

    Pedrozo-Peñafiel, E.; Vivanco, F.; Castilho, P.; Paiva, R. R.; Farias, K. M.; Bagnato, V. S.

    2016-06-01

    The atom source is a relevant component in many atomic molecular optics experiments. The compactness and efficiency of the source are fundamental issues, acquiring more importance as the complexity of the experiments increases. Characterizing new techniques to produce high atom flux is necessary to know the efficiency and peculiarities of each one. This allows choosing the most suitable source for a specific experiment. In this work, we show a direct comparison between a two-dimensional magneto-optical trap (2D-MOT) and a Zeeman slower (ZS) as source of cold sodium atoms to load a standard three-dimensional magneto-optical trap. The optimum parameters for each case are obtained by observing the loading rate and the final number of atoms in the 3D-MOT. We conclude that the 2D-MOT provides a high flux of atoms comparable with that produced by the ZS, but with an enormous advantage with respect to the size of the apparatus.

  17. A novel analytical system involving hydride generation and gold-coated W-coil trapping atomic absorption spectrometry for selenium determination at ng l-1 level

    A novel analytical technique was developed where gaseous hydrogen selenide formed by sodium tetrahydroborate reduction is transported to and trapped on a resistively heated gold-coated W-coil atom trap for in situ preconcentration. Gold coating on W-coil was prepared by using an organic solution of Au. The atom trap is held at 165 oC during the collection stage and is heated up to 675 deg. C for revolatilization; analyte species formed are transported to an externally heated quartz T-tube where the atomization takes place and the transient signal is obtained. The carrier gas consisted of 112.5 ml min-1 Ar with 75 ml min-1 H2 during the collection step and 112.5 ml min-1 Ar with 450 ml min-1 H2 in the revolatilization step. The half width of the transient signal obtained is less than 0.5 s. The RSD for the measurements was found to be 3.9% (n = 11) for 0.10 μg l-1 Se using peak height measurements. The calibration plot for 27.0 ml of sample collected in 4.0 min using a flow rate of 6.75 ml min-1 was linear between 0.13 and 2.0 μg l-1 of Se. The limit of detection (3 s) is 39 ng l-1. The enhancement factor for the characteristic concentration (Co) was found to be 20.1 when compared to conventional hydride generation atomic absorption spectrometry system without trap. In order to check the accuracy of the method, standard reference material, natural water NIST 1640 was employed; the result was found to be in good agreement with the certified value at the 95% confidence level

  18. Electromagnetically induced transparency and four-wave mixing in a cold atomic ensemble with large optical depth

    We report on the delay of optical pulses using electromagnetically induced transparency (EIT) in an ensemble of cold atoms with an optical depth exceeding 500. To identify the regimes in which four-wave mixing (4WM) impacts on EIT behaviour, we conduct the experiment in both 85Rb and 87Rb. Comparison with theory shows excellent agreement in both isotopes. In 87Rb negligible 4WM was observed and we obtained one pulse-width of delay with 50% efficiency. In 85Rb 4WM contributes to the output. In this regime we achieve a delay-bandwidth product of 3.7 at 50% efficiency, allowing temporally multimode delay, which we demonstrate by compressing two pulses into the memory medium. (paper)

  19. Ambient-Temperature Trap/Release of Arsenic by Dielectric Barrier Discharge and Its Application to Ultratrace Arsenic Determination in Surface Water Followed by Atomic Fluorescence Spectrometry.

    Mao, Xuefei; Qi, Yuehan; Huang, Junwei; Liu, Jixin; Chen, Guoying; Na, Xing; Wang, Min; Qian, Yongzhong

    2016-04-01

    A novel dielectric barrier discharge reactor (DBDR) was utilized to trap/release arsenic coupled to hydride generation atomic fluorescence spectrometry (HG-AFS). On the DBD principle, the precise and accurate control of trap/release procedures was fulfilled at ambient temperature, and an analytical method was established for ultratrace arsenic in real samples. Moreover, the effects of voltage, oxygen, hydrogen, and water vapor on trapping and releasing arsenic by DBDR were investigated. For trapping, arsenic could be completely trapped in DBDR at 40 mL/min of O2 input mixed with 600 mL/min Ar carrier gas and 9.2 kV discharge potential; prior to release, the Ar carrier gas input should be changed from the upstream gas liquid separator (GLS) to the downstream GLS and kept for 180 s to eliminate possible water vapor interference; for arsenic release, O2 was replaced by 200 mL/min H2 and discharge potential was adjusted to 9.5 kV. Under optimized conditions, arsenic could be detected as low as 1.0 ng/L with an 8-fold enrichment factor; the linearity of calibration reached R(2) > 0.995 in the 0.05 μg/L-5 μg/L range. The mean spiked recoveries for tap, river, lake, and seawater samples were 98% to 103%; and the measured values of the CRMs including GSB-Z50004-200431, GBW08605, and GBW(E)080390 were in good agreement with the certified values. These findings proved the feasibility of DBDR as an arsenic preconcentration tool for atomic spectrometric instrumentation and arsenic recycling in industrial waste gas discharge. PMID:26976077

  20. Intense source of cold cesium atoms based on a two-dimensional magneto-optical trap with independent axial cooling and pushing

    Huang, J Q; Wu, C F; Zhang, J W; Feng, Y Y; Wang, L J

    2015-01-01

    We report our studies on an intense source of cold cesium atoms based on a two-dimensional magneto-optical trap with independent axial cooling and pushing. The new-designed source, proposed as 2D-HP MOT, uses hollow laser beams for axial cooling and a thin pushing laser beam for cold atomic beam extraction. Regulated independently by the pushing beam, the atomic flux can be substantially optimized. The atomic flux maximum obtained in the 2D-HP MOT is $4.02\\times 10^{10}$ atoms/s, increased by 60 percent compared to the traditional 2D$^+$ MOT in our experiment. Moreover, with the pushing power 10 $\\mu$W and detuning $0\\Gamma$, the 2D-HP MOT can generate a rather intense cold cesium atomic beam with the concomitant light shift suppressed by 20 times in magnitude. The axial velocity distribution of the cold cesium beams centers at 6.8 m/s with a FMHW of about 2.8 m/s. The dependences of the atomic flux on the pushing power and detuning are studied. The experimental results are in good agreement with the theoreti...

  1. Two-stage magneto-optical trapping and narrow-line cooling of $^6$Li atoms to high phase-space density

    Sebastian, Jimmy; Li, Ke; Gan, Huat Chai Jaren; Li, Wenhui; Dieckmann, Kai

    2014-01-01

    We report an experimental study of peak and phase-space density of a two-stage magneto-optical trap (MOT) of 6-Li atoms, which exploits the narrower $2S_{1/2}\\rightarrow 3P_{3/2}$ ultra-violet (UV) transition at 323 nm following trapping and cooling on the more common D2 transition at 671 nm. The UV MOT is loaded from a red MOT and is compressed to give a high phase-space density up to $3\\times 10^{-4}$. Temperatures as low as 33 $\\mu$K are achieved on the UV transition. We study the density limiting factors and in particular find a value for the light-assisted collisional loss coefficient of $1.3 \\pm0.4\\times10^{-10}\\,\\textrm{cm}^3/\\textrm{s}$ for low repumping intensity.

  2. Simple Theoretical Models for Resonant Cold Atom Interactions

    Julienne, P S; Julienne, Paul S.; Gao, Bo

    2006-01-01

    Magnetically tunable scattering resonances have been used with great success for precise control of s-wave scattering lengths in ultracold atomic collisions. We describe relatively simple yet quite powerful analytic treatments of such resonances based on the analytic properties of the van der Waals long range potential. This theory can be used to characterize a number of properties of specific resonances that have been used successfully in various experiments with $^{87}$Rb, $^{85}$Rb, $^{40}$K, and $^{6}$Li. Optical Feshbach resonances are also possible and may be practical with narrow intercombination line photoassociative transitions in species like Sr and Yb.

  3. Atoms

    刘洪毓

    2007-01-01

    Atoms(原子)are all around us.They are something like the bricks (砖块)of which everything is made. The size of an atom is very,very small.In just one grain of salt are held millions of atoms. Atoms are very important.The way one object acts depends on what

  4. Atoms

    Completed by recent contributions on various topics (atoms and the Brownian motion, the career of Jean Perrin, the evolution of atomic physics since Jean Perrin, relationship between scientific atomism and philosophical atomism), this book is a reprint of a book published at the beginning of the twentieth century in which the author addressed the relationship between atomic theory and chemistry (molecules, atoms, the Avogadro hypothesis, molecule structures, solutes, upper limits of molecular quantities), molecular agitation (molecule velocity, molecule rotation or vibration, molecular free range), the Brownian motion and emulsions (history and general features, statistical equilibrium of emulsions), the laws of the Brownian motion (Einstein's theory, experimental control), fluctuations (the theory of Smoluchowski), light and quanta (black body, extension of quantum theory), the electricity atom, the atom genesis and destruction (transmutations, atom counting)

  5. Analytic Solutions of Three-Level Dressed-Atom Model

    WANG Zheng-Ling; YIN Jian-Ping

    2004-01-01

    On the basis of the dressed-atom model, the general analytic expressions for the eigenenergies, eigenstates and their optical potentials of the A-configuration three-level atom system are derived and analysed. From the calculation of dipole matrix element of different dressed states, we obtain the spontaneous-emission rates in the dressed-atom picture. We find that our general expressions of optical potentials for the three-level dressed atom can be reduced to the same as ones in previous references under the approximation of a small saturation parameter. We also analyse the dependences of the optical potentials of a three-level 85Rb atom on the laser detuning and the dependences of spontaneous-emission rates on the radial position in the dark hollow beam, and discuss the probability (population) evolutions of dressed-atomic eigenstates in three levels in the hollow beam.

  6. Comparison of fission gas products accumulated in the irradiated UO2 fuel with the radiogenic gas trapped in minerals containing fissile atoms

    Both the old mineral materials containing fissile isotopes and the neutron irradiated uranium dioxide fuel hold fairly a lot of noble gases. Appreciable fraction of the inert gases is immobilized in the uranium dioxide fuel after irradiation exposure in excess of 1015 fissions/cm3. Spontaneous fission fluency for the minerals containing fissile atoms of about 2 billions years old is about 1015 fissions/cm3. Alike the old minerals containing fissile isotopes and the irradiated UO2 fuel reveal during annealing three peaks of gas release in the low temperature range. In the range only several percent of the total amount of gas as well in the mineral materials and the uranium dioxide fuel is released. It still holds significant part of noble gases after annealing at a temperature about 1400 deg C. Noble gas atoms can be trapped by the point defects, clusters of the point defects, clathrates and small bubbles in the irradiated material. It is suggested that above a fission fluency threshold about 1015 fissions/cm3 occurs an additional trapping process based on the irradiation induced chemical bonding process. It is inferred further that as well in the minerals and in the irradiated UO2 fuel the gas release kinetics is determined by the kinetics of thermal recovery of the radiation induced defects in the low temperature range. It is surmised that the same amount of damage caused by alpha decay of uranium is much less effective than caused by fission of uranium for the immobilization of noble gases since only during fissioning there are formed conditions for strong chemical binding between the noble gas atoms and the mineral materials. Finally it is concluded identical nature of noble gas accumulation mechanisms in the irradiated UO2 fuel and in the old mineral materials containing fissile atoms. (author)

  7. The temperature of optical molasses for two different atomic angular momenta

    We have measured the temperature of laser-cooled Rb atoms in optical molasses as a function of laser intensity and detuning. For both 85Rb and 87Rb, cooled on the F=3→F'=4 and F=2→F'=3 transitions, respectively, the temperatures are proportional to the ratio of laser power and detuning for a wide range of these parameters. We observe a small but significant difference betwee the two isotopes. We also show the results of three-dimensional semi-classical numerical calculations. Our results favor a model which includes atomic localization in optical standing waves. (orig.)

  8. Quantum Wigner molecules in semiconductor quantum dots and cold-atom optical traps and their mathematical symmetries

    Yannouleas, Constantine

    2016-01-01

    Strong repelling interactions between a few fermions or bosons confined in two-dimensional circular traps lead to particle localization and formation of quantum Wigner molecules (QWMs) possessing definite point-group space symmetries. These point-group symmetries are "hidden" (or emergent), namely they cannot be traced in the circular single-particle densities (SPDs) associated with the exact many-body wave functions, but they are manifested as characteristic signatures in the ro-vibrational spectra. An example, among many, are the few-body QWM states under a high magnetic field or at fast rotation, which are precursor states for the fractional quantum Hall effect. The hidden geometric symmetries can be directly revealed by using spin-resolved conditional probability distributions, which are extracted from configuration-interaction (CI), exact-diagonalization wave functions. The hidden symmetries can also be revealed in the CI SPDs by reducing the symmetry of the trap (from circular to elliptic to quasi-linea...

  9. Bright solitons and self-trapping with a BEC of cold atoms in driven tilted optical lattices

    Kolovsky, Andrey R.

    2010-01-01

    We suggest a method for creating bright matter solitons by loading a BEC of atoms in a driven tilted optical lattice. It is shown that one can realize the self-focussing regime for the wave-packet dynamics by properly adjusting the phase of the driving field with respect to the phase of Bloch oscillations. If atom-atom interactions are larger than some critical value $g_{min}$, this self-focussing regime is followed by the formation of bright solitons. Increasing the interactions above anothe...

  10. Atom Chips

    Folman, R; Cassettari, D; Hessmo, B; Maier, T; Schmiedmayer, J; Folman, Ron; Krüger, Peter; Cassettari, Donatella; Hessmo, Björn; Maier, Thomas

    1999-01-01

    Atoms can be trapped and guided using nano-fabricated wires on surfaces, achieving the scales required by quantum information proposals. These Atom Chips form the basis for robust and widespread applications of cold atoms ranging from atom optics to fundamental questions in mesoscopic physics, and possibly quantum information systems.

  11. A HBAR-oscillator-based 4.596~GHz frequency source: Application to a coherent population trapping Cs vapor cell atomic clock

    Daugey, Thomas; Martin, Gilles; Boudot, Rodolphe

    2015-01-01

    This article reports on the design and characterization of a high-overtone bulk acoustic wave resonator (HBAR)-oscillator-based 4.596~GHz frequency source. A 2.298~GHz signal, generated by an oscillator constructed around a thermally-controlled two-port AlN-sapphire HBAR resonator with a Q-factor of 24000 at 68$^{\\circ}$C, is frequency multiplied by 2 to 4.596~GHz, half of the Cs atom clock frequency. The temperature coefficient of frequency (TCF) of the HBAR is measured to be $-23$~ppm/$^{\\circ}$C at 2.298~GHz. The measured phase noise of the 4.596~GHz source is $-105$~dBrad$^2$/Hz at 1~kHz offset and $-150$~dBrad$^2$/Hz at 100~kHz offset. The 4.596~GHz output signal is used as a local oscillator (LO) in a laboratory-prototype Cs microcell-based coherent population trapping (CPT) atomic clock. The signal is stabilized onto the atomic transition frequency by tuning finely a voltage-controlled phase shifter (VCPS) implemented in the 2.298~GHz HBAR-oscillator loop, preventing the need for a high-power-consuming...

  12. New cryogenic trap design for speciation analysis of Arsenic by generation of substituted hydrides-atomic absorption spectrometry

    Svoboda, Milan; Kratzer, Jan; Dědina, Jiří

    2014. s. 196-196. [Rio Symposium on Atomic Spectrometry /13./. 19.10.2014-24.10.2014, Merida, Yucatan] R&D Projects: GA ČR GA14-23532S Institutional support: RVO:68081715 Keywords : cryotrapping * hydride generation * arsenic speciation analysis Subject RIV: CB - Analytical Chemistry, Separation

  13. Determination of nickel by flow injection nickel tetracarbonyl generation and in situ trapping graphite furnace atomic absorption spectrometry

    Marek, P.; Dočekal, Bohumil

    Košice : Štroffek publishing, 1998, s. 60-66. [Seminar on Atomic Spectrochemistry /14./. Podbánske (SK), 07.09.1998-11.09.1998] R&D Projects: GA ČR GA203/98/0754 Subject RIV: CB - Analytical Chemistry, Separation

  14. An Improved Antihydrogen Trap

    Kalra, Rita Rani

    2015-01-01

    The recent demonstration of trapped atomic antihydrogen for 15 to 1000 seconds is a milestone towards precise spectroscopy for tests of CPT invariance. The confinement of a total of 105±21 atoms in a quadrupole magnetic trap was made possible by several improved methods. Improved accumulation techniques give us the largest numbers of constituent particles yet: up to 10 million antiprotons and several billion positrons. A novel cooling protocol leads to 3.5 K antiprotons, the coldest ever obse...

  15. Retraction notice to "Measurements of total absolute collision cross section of ultracold Rb atom using magneto-optic and pure magnetic traps" [Chinese Optics Letters 9, 060201 (2011)

    Jicheng Wang; Yueyuan Wang; Yueke Wang; Guangyu Fang; Shutian Liu

    2011-01-01

    This article "Measurements of total absolute collision cross section of ultracold Rb atom using magneto-optic and pure magnetic traps",which was published on Chinese Optics Letters (9,060201 (2011)) has been retracted at the request of the authors.Reason:The first author,Jicheng Wang,participated in a related research in Professor Kirk Madison's group in the Department of Physics & Astronomy at the University of British Columbia,Canada from September 2008 to February 2010.Some of the experimental data have not been authorized for publication,even though they have been consented to be used by Jicheng Wang in his own research.The authors apologize to Professor K.Madison for misunderstanding,and to Chinese Optics Letters and the readers of Chinese Optics Letters for any inconvenience this mistake may have caused.

  16. Guest Editor’s Notes on the “Atoms” Special Issue on “Perspectives of Atomic Physics with Trapped Highly Charged Ions”

    Elmar Träbert

    2016-02-01

    Full Text Available The study of highly charged ions (HCI was pursued first at Uppsala (Sweden, by Edlén and Tyrén in the 1930s. Their work led to the recognition that the solar corona is populated by such ions, an insight which forced massive paradigm changes in solar physics. Plasmas aiming at controlled fusion in the laboratory, laser-produced plasmas, foil-excited swift ion beams, and electron beam ion traps have all pushed the envelope in the production of HCI. However, while there are competitive aspects in the race for higher ion charge states, the real interest lies in the very many physics topics that can be studied in these ions. Out of this rich field, the Special Issue concentrates on atomic physics studies that investigate highly charged ions produced, maintained, and/or manipulated in ion traps. There have been excellent achievements in the field in the past, and including fairly recent work, they have been described by their authors at conferences and in the appropriate journals. The present article attempts an overview over current lines of development, some of which are expanded upon in this Special Issue.

  17. Three-photon coherence of Rydberg atomic states

    Kwak, Hyo Min; Jeong, Taek; Lee, Yoon-Seok; Moon, Han Seb

    2016-05-01

    We investigated three-photon coherence effects of the Rydberg state in a four-level ladder-type atomic system for the 5 S1/2 (F = 3) - 5 P3/2 (F' = 4) - 50 D5/2 - 51 P3/2 transition of 85 Rb atoms. By adding a resonant electric field of microwave (MW) at electromagnetically induced transparency (EIT) in Rydberg state scheme, we observed experimentally that splitting of EIT signal appears under the condition of three-photon resonance in the Doppler-broadened atomic system. Discriminating the two- and three-photon coherence terms from the calculated spectrum in a simple four-level ladder-type Doppler-broadened atomic system, we found that the physical origin of splitting of EIT was three-photon coherence effect, but not three-photon quantum interference phenomena such as three-photon electromagnetically induced absorption (TPEIA).

  18. Contrast and phase-shift of a trapped atom interferometer using a thermal ensemble with internal state labelling

    Dupont-Nivet, M; Schwartz, S

    2016-01-01

    We report a theoretical study of a double-well Ramsey interferometer using internal state labelling. We consider the use of a thermal ensemble of cold atoms rather than a Bose-Einstein condensate to minimize the effects of atomic interactions. To maintain a satisfactory level of coherence in this case, a high degree of symmetry is required between the two arms of the interferometer. Assuming that the splitting and recombination processes are adiabatic, we theoretically derive the phase-shift and the contrast of such an interferometer in the presence of gravity or an acceleration field. We also consider using a "shortcut to adiabaticity" protocol to speed up the splitting process and discuss how such a procedure affects the phase shift and contrast. We find that the two procedures lead to phase-shifts of the same form.

  19. Amplified light storage with high fidelity based on electromagnetically induced transparency in rubidium atomic vapor

    Zhou, Wei; Wang, Gang; Tang, Guoyu; Xue, Yan

    2016-06-01

    By using slow and stored light based on electromagnetically induced transparency (EIT), we theoretically realize the storage of optical pulses with enhanced efficiency and high fidelity in ensembles of warm atoms in 85Rb vapor cells. The enhancement of storage efficiency is achieved by introducing a pump field beyond three-level configuration to form a N-type scheme, which simultaneously inhibits the undesirable four-wave mixing effect while preserves its fidelity. It is shown that the typical storage efficiency can be improved from 29% to 53% with the application of pump field. Furthermore, we demonstrate that this efficiency decreases with storage time and increases over unity with optical depth.

  20. Trapping and diffusion of noble gas atoms in some off-stoichiometric ceramics studied by thermal desorption spectrometry. Doctoral thesis

    Hoondert, W.H.B.

    1993-01-01

    The thesis deals with the mobility of small noble gas atoms, mainly helium, in ceramic materials with high defect concentrations. Hence, two subjects are covered: diffusion and defect physics. The experimental technique employed is Thermal Desorption Spectrometry (TDS). An introductory outline of TDS is given. The present study was initiated for various reasons. First of all, research on helium retention and mobility behavior, such as bubble nucleation and subsequent bubble migration, in potential fusion reactor wall materials (which some of the ceramics are) is of practical interest. Secondly, because the ceramic materials investigated in the present work have defect concentrations on the order of percents, and because they are binary compounds where in principle more defect types can be present than in pure materials, the defect physics is more complicated and diverse than e.g., in simple metals. Finally, high defective materials can serve as a model system for thin films produced by Ion Beam Assisted Deposition (IBAD). TDS as an analytical tool is of key importance to be able to control the IBAD process, and for the understanding of the atomic-scale phenomena involved.

  1. A high-overtone bulk acoustic wave resonator-oscillator-based 4.596 GHz frequency source: Application to a coherent population trapping Cs vapor cell atomic clock

    This article reports on the design and characterization of a high-overtone bulk acoustic wave resonator (HBAR)-oscillator-based 4.596 GHz frequency source. A 2.298 GHz signal, generated by an oscillator constructed around a thermally controlled two-port aluminum nitride-sapphire HBAR resonator with a Q-factor of 24 000 at 68 °C, is frequency multiplied by 2–4.596 GHz, half of the Cs atom clock frequency. The temperature coefficient of frequency of the HBAR is measured to be −23 ppm/ °C at 2.298 GHz. The measured phase noise of the 4.596 GHz source is −105 dB rad2/Hz at 1 kHz offset and −150 dB rad2/Hz at 100 kHz offset. The 4.596 GHz output signal is used as a local oscillator in a laboratory-prototype Cs microcell-based coherent population trapping atomic clock. The signal is stabilized onto the atomic transition frequency by tuning finely a voltage-controlled phase shifter implemented in the 2.298 GHz HBAR-oscillator loop, preventing the need for a high-power-consuming direct digital synthesis. The short-term fractional frequency stability of the free-running oscillator is 1.8 × 10−9 at one second integration time. In locked regime, the latter is improved in a preliminary proof-of-concept experiment at the level of 6.6 × 10−11 τ−1/2 up to a few seconds and found to be limited by the signal-to-noise ratio of the detected CPT resonance

  2. Spectroscopy and isotope shifts of the 4s3d 1D2-4s5p 1P1 repumping transition in magneto-optically trapped calcium atoms

    We investigate a repumping scheme for magneto-optically trapped calcium atoms. It is based on excitation of the 4s3d1D2-4s5p1P1 transition at 672 nm with an extended cavity diode laser. The effect of the repumping is approximately a factor of three increase in trap lifetime and a doubling of the trapping efficiency from a Zeeman slowed thermal beam. Added to this, the 672-nm laser repumps atoms from an otherwise dark state to yield an overall increase in detected fluorescence signal from the magneto-optic trap (MOT) of more than an order of magnitude. Furthermore, we report isotope shift measurements of the 672-nm transition, for the first time, for four naturally occurring even isotopes. Using available charge radii data, the observed shifts, extending up to 4.3 GHz, display the expected linear dependence in a King plot analysis. The measured shifts are used to determine the isotope shifts of the remaining 41,43,46Ca isotopes. These might be of interest where less abundant isotopes are used enabling isotope selective repumping, resulting in enhanced trapping and detection efficiencies.

  3. Generation of non-classical correlated photon pairs via a ladder-type atomic configuration: theory and experiment

    Ding, Dong-Sheng; Zhou, Zhi-Yuan; Shi, Bao-Sen; Zou, Xu-Bo; Guo, Guang-Can

    2012-01-01

    We experimentally generate a non-classical correlated two-color photon pair at 780 and 1529.4 nm in a ladder-type configuration using a hot 85Rb atomic vapor with the production rate of ~107/s. The non-classical correlation between these two photons is demonstrated by strong violation of Cauchy-Schwarz inequality by the factor R=48+-12. Besides, we experimentally investigate the relations between the correlation and some important experimental parameters such as the single-photon detuning, th...

  4. First observation of the strongly forbidden transition {sup 1}S{sub 0} - {sup 3}P{sub 0} in Strontium, for an atomic clock with trapped atoms; Premiere observation de la transition fortement interdite {sup 1}S{sub 0} - {sup 3}P{sub 0} du strontium, pour une horloge optique a atomes pieges

    Courtillot, I

    2003-11-01

    This thesis reports the first results towards the realization of an optical clock using trapped strontium atoms. This set up would combine advantages of the different approaches commonly used to develop an atomic frequency standard. The first part describes the cold atoms source which is implemented. A magneto-optical trap operating on the {sup 1}S{sub 0}-{sup 1}P{sub 1} transition at 461 nm is loaded from an atomic beam decelerated by a Zeeman slower. The 461 nm laser is obtained by sum-frequency mixing in a potassium titanyl phosphate (KTP) crystal. The second part is devoted to the different stages developed to achieve the direct excitation of the {sup 1}S{sub 0}-{sup 3}P{sub 0} clock transition in {sup 87}Sr. This line has a theoretical natural width of 10{sup -3} Hz. Before this detection, we obtained an estimate of the resonance frequency by measuring absolute frequencies of several allowed optical transitions. (author)

  5. Low interfacial trap density and high-temperature thermal stability in atomic layer deposited single crystal Y2O3/n-GaAs(001)

    Lin, Yen-Hsun; Fu, Chien-Hua; Lin, Keng-Yung; Chen, Kuan-Hsiung; Chang, Tsong-Wen; Raynien Kwo, J.; Hong, Minghwei

    2016-08-01

    A low interfacial trap density (D it) of 2.2 × 1011 eV‑1 cm‑2 has been achieved with an atomic layer deposited (ALD) single crystal Y2O3 epitaxially on n-GaAs(001), along with a small frequency dispersion of 10.3% (2.6%/decade) at the accumulation region in the capacitance–voltage (C–V) curves. The D it and frequency dispersion in the C–V curves in this work are the lowest among all of the reported ALD-oxides on n-type GaAs(001). The D it was measured using the conductance–voltage (G–V) and quasi-static C–V (QSCV) methods. Moreover, the heterostructure was thermally stable with rapid annealing at 900 °C under various durations in He and N2, which has not been achieved in the heterostructures of ALD-Al2O3 or HfO2 on GaAs.

  6. Novel Atomic Mirror with a Blue-Detuned Semi-Gaussian Beam

    郑萍; 高伟建; 印建平

    2003-01-01

    A novel and simple atomic mirror composed of a blue-detuned semi-Gaussian beam is proposed. From the Fresnel diffraction theory, the intensity distributions of a collimated GaUssian laser beam diffracted by the straight edge of a semi-infinite opaque plate are studied. The optical potential of the semi-Gaussian beam for 85 Rb atoms and its spontaneous emission probability are calculated and compared with the performance of the evanescent-wave mirror. Our study shows that the blue-detuned semi-Gaussian beam, as a novel atomic mirror, can be used to reflect atomic beam efliciently, and under the same beam parameters and lower normal atomic velocity, the performance of the semi-Gaussian-beam mirror is better than that of the evanescent-wave mirror.

  7. Phosphorous trapped within buckminsterfullerene

    Larsson, J. A.; Greer, J. C.; Harneit, W.; Weidinger, A.

    2002-05-01

    Under normal circumstances, when covalent molecules form, electrons are exchanged between atoms to form bonds. However, experiment and theoretical computations reveal exactly the opposite effect for the formation of group V elements nitrogen and phosphorous encapsulated within a buckminsterfullerene molecule. The C60 carbon cage remains intact upon encapsulation of the atom, whereas the electronic charge cloud of the N or P atom contracts. We have studied the chemical, spin, and thermodynamic properties of endohedral phosphorous (P@C60) and have compared our results with earlier findings for N@C60. From a combined experimental and theoretical vantage, we are able to elucidate a model for the interaction between the trapped group V atom and the fullerene cage. A picture emerges for the electronic structure of these complexes, whereby an atom is trapped within a fullerene, and interacts weakly with the molecular orbitals of the C60 cage.

  8. An Atomic Lens Using a Focusing Hollow Beam

    夏勇; 印建平; 王育竹

    2003-01-01

    We propose a new method to generate a focused hollow laser beam by using an azimuthally distributed 2π-phase plate and a convergent thin lens, and calculate the intensity distribution of the focused hollow beam in free propagation space. The relationship between the waist w0 of the incident collimated Gaussian beam and the dark spot size of the focused hollow beam at the focal point, and the relationship between the focal length f of the thin lens and the dark spot size are studied respectively. The optical potential of the blue-detuned focused hollow beam for 85Rb atoms is calculated. Our study shows that when the larger waist w of the incident Gaussian beam and the shorter focal length f of the lens are chosen, we can obtain an extremely small dark spot size of the focused hollow beam, which can be used to form an atomic lens with a resolution of several angstroms.

  9. Determination of silver at ng mL-1 levels by preconcentration on a W-coil trap and hydride generation atomic absorption spectrometry

    Complete text of publication follows. A classical hydride generation atomic absorption spectrometry flow system consists of a reaction coil, a stripping coil, a gas liquid separator (GLS) and a heated quartz T-tube atomizer. There have been some studies for determination of Ag by using this classical hydride generation system; however, only mg L-1 levels could be determined. In this study, three types of gas-liquid separators, namely, U-shape, cylindrical and a novel large volume device were used. It was possible to determine Ag in ng mL-1 level when stripping coil was eliminated from the system. The calibration plot was linear in the range of 50 to 500 ng mL-1 using a U-shape GLS. The 3s limit of detection (LOD) is 29 ng mL-1 and characteristic concentration value, C0, were found to be 15.3 ng mL-1. The similar set-up was used also with a cylindrical GLS; it was observed that the efficiency of this GLS is about 10 fold higher than the U-shape GLS; linear working range was 5.0 to 50 ng mL-1. LOD (3s) and C0 values were found to be 3.0 ng mL-1 and 2.9 ng mL-1, respectively. In order to minimize the memory effects, a 10% (v/v) solution of dichlorodimethylsilane in toluene was used to silanize both gas liquid separators to deactivate their internal surfaces. In addition to these studies, a novel large volume GLS was used. In this device 15.0 mL of mixed acidic analyte solution and NaBH4 were placed. Argon gas was passed through this mixture for 90 seconds and formed volatile analyte species were sent to a W-coil trap heated at an optimized temperature. The calibration plot was linear between 0.10 and 0.75 ng mL-1; the LOD (3s) and C0 were found to be 0.049 ng mL-1 and 0.050 ng mL-1, respectively.

  10. Generation of One-Dimensional Array of Focused Hollow-Beam Pipes and Its Surface Microscopic Waveguide for Cold Atoms or Molecules

    JI Xian-Ming; XIA Yong; YIN Jian-Ping

    2004-01-01

    We propose a new scheme to guide cold atoms (or molecules) by using a one-dimensional (1D) array of focused hollow-beam pipes generated by the combination of a binary phase grating and a 1D array of micro-cylindrical lenses on the substrate surface. We also calculate the intensity distribution of the focused hollow-beam pipe array and its optical potential for 85Rb atoms. The result shows that when the blue detuning of the incident beam and its intensity are 10 GHz and 7.0 × 103 W/m2 respectively, the horizontal dark spot size of each focused hollow-beam pipe and the efficient optical potential are 4.4μm and ~ 0.23mK, which is high enough to guide cold 85Rb atoms (~ 20 μK) from a standard optical molasses and then to realize the 1D array of surface atomic waveguides on an atom chip.

  11. Trapped Surfaces

    Senovilla, José M. M.

    2013-03-01

    I review the definition and types of (closed) trapped surfaces. Surprising global properties are pointed out, such as their "clairvoyance" and the possibility that they enter into flat portions of the spacetime. Several results on the interplay of trapped surfaces with vector fields and with spatial hypersurfaces are presented. Applications to the quasi-local definition of Black Holes are analyzed, with particular emphasis set onto marginally trapped tubes, trapping horizons and the boundary of the region with closed trapped surfaces. Finally, the core of a trapped region is introduced, and its importance briefly discussed.

  12. Trapped surfaces

    Senovilla, José M M

    2011-01-01

    I review the definition and types of (closed) trapped surfaces. Surprising global properties are shown, such as their "clairvoyance" and the possibility that they enter into flat portions of the spacetime. Several results on the interplay of trapped surfaces with vector fields and with spatial hypersurfaces are presented. Applications to the quasi-local definition of Black Holes are discussed, with particular emphasis set onto marginally trapped tubes, trapping horizons and the boundary of the region with closed trapped surfaces. Finally, the core of a trapped region is introduced, and its importance discussed.

  13. Trapped surfaces

    Senovilla, José M. M.

    2011-01-01

    I review the definition and types of (closed) trapped surfaces. Surprising global properties are shown, such as their "clairvoyance" and the possibility that they enter into flat portions of the spacetime. Several results on the interplay of trapped surfaces with vector fields and with spatial hypersurfaces are presented. Applications to the quasi-local definition of Black Holes are discussed, with particular emphasis set onto marginally trapped tubes, trapping horizons and the boundary of th...

  14. Atom Skimmers and Atom Lasers Utilizing Them

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  15. Atomic Physics

    Foot, Christopher J

    2007-01-01

    This text will thoroughly update the existing literature on atomic physics. Intended to accompany an advanced undergraduate course in atomic physics, the book will lead the students up to the latest advances and the applications to Bose-Einstein Condensation of atoms, matter-wave inter-ferometry and quantum computing with trapped ions. The elementary atomic physics covered in the early chapters should be accessible to undergraduates when they are first introduced to the subject. To complement. the usual quantum mechanical treatment of atomic structure the book strongly emphasizes the experimen

  16. Atoms Talking to SQUIDs

    2011-01-01

    We present a scheme to couple trapped $^{87}$Rb atoms to a superconducting flux qubit through a magnetic dipole transition. We plan to trap atoms on the evanescent wave outside an ultrathin fiber to bring the atoms to less than 10 $\\mu$m above the surface of the superconductor. This hybrid setup lends itself to probing sources of decoherence in superconducting qubits. Our current plan has the intermediate goal of coupling the atoms to a superconducting LC resonator.

  17. Decoherence via induced dipole collisions in an ultracold gas

    Gorges, Anthony R; Roberts, Jacob L

    2009-01-01

    We have studied the effects of loading $^{87}$Rb into a far off resonant trap (FORT) in the presence of an ultracold cloud of $^{85}$Rb. The presence of the $^{85}$Rb resulted in a marked decrease of the $^{87}$Rb load rate. This decrease is consistent with a decrease in the laser cooling efficiency needed for effective loading. While many dynamics which disrupt loading efficency arise when cooling in a dense cloud of atoms (reabsorption, adverse optical pumping, etc.), the large detuning between the transitions of $^{85}$Rb and $^{87}$Rb should isolate the isotopes from these effects. For our optical molasses conditions we calculate that our cooling efficiencies require induced ground-state coherences. We present data and estimates which are consistent with heteronuclear long-ranged induced dipole-dipole collisions disrupting these ground state coherences, leading to a loss of optical trap loading efficiency.

  18. 全光学冷却与囚禁133Cs原子玻色-爱因斯坦凝聚的可能性%POSSIBILITY OF ALL OPTICALLY-COOLED AND TRAPPED 133Cs ATOMIC BEC

    印建平; 高伟建; 刘南春; 王义遒

    2001-01-01

    The experimental progress on rf evaporative cooling of 133Cs atomic sample in recent year is reviewed, and the difficulty of magnetically trapped 133Cs atomic Bose-Einstein condensation (BEC) is analyzed. In this paper, we propose an all-optically-cooled and -trapped 133Cs BEC scheme, which is composed of a pyramidal-hollow-beam gravito-optical trap (PHB GOT) from a diode laser (λ=0.852 μm) and a conical-hollow-beam (CHB) GOT from an Ar+ laser (=0.5013 μm). In the PHB GOT, the cold atoms experience an efficient hollow-beam induced Sisyphus cooling (i.e., intensity gradient cooling) and repumpimg-beam induced geometric cooling, and they will be cooled to a few photon-recoil limits (~2 μK) from MOT's temperature (~60 μK). Whereas in the Ar+ hollow-laser-beam trap, cold atoms will be further cooled by Raman cooling (or velocity-selection coherent population trapping) and compressed by a blue-detuned covering beam. We have performed Monte-Carlo simulations for PHB cooling process, calculated the optical potential for 133Cs atoms in Ar+ hollow laser beam, and estimated total collision loss and atomic density. Our study shows that the realization of an optically-cooled and -trapped BEC of 133Cs atoms may be possible in our all-optical dipole trap.%综述了近年来有关蒸发冷却133Cs原子样品的实验进展,分析了磁囚禁133Cs原子玻色-爱因斯坦凝聚(BEC)的困难,并在此基础上提出了一个全光型冷却与囚禁133Cs原子BEC的新方案.该方案主要由一个来自半导体激光(λ=0.852 μm)的倒金字塔形中空光束重力光学囚禁(pyramidal-hollow-beam gravito-optical trap,缩写为PHB GOT)和一个来自Ar+激光(=0.5013 μm)的圆锥形中空光束重力光学囚禁(conical-hollow-beam gravito-optical trap,缩写为CHB GOT)组成.在PHB GOT中,冷原子经历了一个有效的中空光束感应的Sisyphus冷却(也即强度梯度冷却)和抽运光感应的几何冷却,原子温度将被从

  19. Trapping interference effects of arsenic, antimony and bismuth hydrides in collection of selenium hydride within iridium-modified transversally-heated graphite tube atomizer

    Furdíková, Zuzana; Dočekal, Bohumil

    2009-01-01

    Roč. 64, č. 4 (2009), s. 323-328. ISSN 0584-8547 R&D Projects: GA ČR GA203/06/1441 Institutional research plan: CEZ:AV0Z40310501 Keywords : selenium hydride trapping * arsine * stibine Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.719, year: 2009

  20. Guiding cold atoms in a hollow laser beam

    Xu, Xinye; Minogin, V. G.; Lee, Kwanil; Wang, Yuzhu; Jhe, Wonho

    1999-12-01

    The theory of atom guiding in a far blue-detuned hollow laser beam (HLB) is developed for the dipole interaction scheme described by a three-level Λ model. The complete kinetic description of atomic motion based on the Fokker-Planck equation for the atomic distribution function is presented. The dipole gradient force, radiation pressure force, and momentum diffusion tensor are then derived. It is found that even for a far-detuned laser beam, the optical potential for a three-level Λ atom is not generally reduced to a sum of two independent potentials associated with the two two-level interactions in the Λ scheme. The theory developed here is also compared with the experimental guiding of cold 85Rb atoms in the HLB. The experimental results are found to be in good agreement with the Monte Carlo simulations based on the three-level Λ model. We observe that the guiding efficiency depends strongly on the intensity and the detuning of the HLB and the initial temperature of atoms. In particular, the experimental results show that, at small detunings, the guiding efficiency is deteriorated strongly by the radiation pressure force. The Monte Carlo simulations also indicate that the efficiency of guiding versus detuning depends strongly on the direction of the HLB propagation with respect to that of atomic motion. Under optimal conditions, the guiding efficiency was found to be about 20%.

  1. Millimeter Wave Detection via Autler-Townes Splitting in Rubidium Rydberg Atoms

    Gordon, Joshua A; Schwarzkopf, Andrew; Anderson, Dave A; Miller, Stephanie; Thaicharoen, Nithiwadee; Raithel, Georg

    2014-01-01

    In this paper we demonstrate the detection of millimeter waves via Autler-Townes splitting in 85Rb Rydberg atoms. This method may provide an independent, atom-based, SI-traceable method for measuring mm-wave electric fields, which addresses a gap in current calibration techniques in the mm-wave regime. The electric- field amplitude within a rubidium vapor cell in the WR-10 waveguide band is measured for frequencies of 93 GHz, and 104 GHz. Relevant aspects of Autler-Townes splitting originating from a four-level electromagnetically induced transparency scheme are discussed. We measure the E-field generated by an open-ended waveguide using this technique. Experimental results are compared to a full-wave finite element simulation.

  2. Perforated hollow-core optical waveguides for on-chip atomic spectroscopy and gas sensing

    Giraud-Carrier, M.; Hill, C.; Decker, T.; Black, J. A.; Schmidt, H.; Hawkins, A.

    2016-03-01

    A hollow-core waveguide structure for on-chip atomic spectroscopy is presented. The devices are based on Anti-Resonant Reflecting Optical Waveguides and may be used for a wide variety of applications which rely on the interaction of light with gases and vapors. The designs presented here feature short delivery paths of the atomic vapor into the hollow waveguide. They also have excellent environmental stability by incorporating buried solid-core waveguides to deliver light to the hollow cores. Completed chips were packaged with an Rb source and the F = 3 ≥ F' = 2, 3, 4 transitions of the D2 line in 85Rb were monitored for optical absorption. Maximum absorption peak depths of 9% were measured.

  3. Ion trap in a semiconductor chip

    Stick, D.; Hensinger, W. K.; Olmschenk, S.; Madsen, M. J.; Schwab, K.; Monroe, C.

    2006-01-01

    The electromagnetic manipulation of isolated atoms has led to many advances in physics, from laser cooling and Bose-Einstein condensation of cold gases to the precise quantum control of individual atomic ions. Work on miniaturizing electromagnetic traps to the micrometre scale promises even higher levels of control and reliability. Compared with `chip traps' for confining neutral atoms, ion traps with similar dimensions and power dissipation offer much higher confinement forces and allow unparalleled control at the single-atom level. Moreover, ion microtraps are of great interest in the development of miniature mass-spectrometer arrays, compact atomic clocks and, most notably, large-scale quantum information processors. Here we report the operation of a micrometre-scale ion trap, fabricated on a monolithic chip using semiconductor micro-electromechanical systems (MEMS) technology. We confine, laser cool and measure heating of a single 111Cd+ ion in an integrated radiofrequency trap etched from a doped gallium-arsenide heterostructure.

  4. Ion Trap in a Semiconductor Chip

    Stick, D; Olmschenk, S; Madsen, M J; Schwab, K; Monroe, C

    2006-01-01

    The electromagnetic manipulation of isolated atoms has led to many advances in physics, from laser cooling and Bose-Einstein condensation of cold gases to the precise quantum control of individual atomic ion. Work on miniaturizing electromagnetic traps to the micrometer scale promises even higher levels of control and reliability. Compared with 'chip traps' for confining neutral atoms, ion traps with similar dimensions and power dissipation offer much higher confinement forces and allow unparalleled control at the single-atom level. Moreover, ion microtraps are of great interest in the development of miniature mass spectrometer arrays, compact atomic clocks, and most notably, large scale quantum information processors. Here we report the operation of a micrometer-scale ion trap, fabricated on a monolithic chip using semiconductor micro-electromechanical systems (MEMS) technology. We confine, laser cool, and measure heating of a single 111Cd+ ion in an integrated radiofrequency trap etched from a doped gallium...

  5. Atom cooling with an atom-optical diode on a ring

    Ruschhaupt, A.; Muga, J. G.

    2008-01-01

    We propose a method to cool atoms on a ring by combining an atom diode -a laser valve for one-way atomic motion which induces robust internal state excitation- and a trap. We demonstrate numerically that the atom is efficiently slowed down at each diode crossing, and it is finally trapped when its velocity is below the trap threshold.

  6. Moving Single Atoms

    Stuart, Dustin

    2016-05-01

    Single neutral atoms are promising candidates for qubits, the fundamental unit of quantum information. We have built a set of optical tweezers for trapping and moving single Rubidium atoms. The tweezers are based on a far off-resonant dipole trapping laser focussed to a 1 μm spot with a single aspheric lens. We use a digital micromirror device (DMD) to generate dynamic holograms of the desired arrangement of traps. The DMD has a frame rate of 20 kHz which, when combined with fast algorithms, allows for rapid reconfiguration of the traps. We demonstrate trapping of up to 20 atoms in arbitrary arrangements, and the transport of a single-atom over a distance of 14 μm with continuous laser cooling, and 5 μm without. In the meantime, we are developing high-finesse fibre-tip cavities, which we plan to use to couple pairs of single atoms to form a quantum network.

  7. S-wave and p-wave scattering in a cold gas of Na and Rb atoms

    Ouerdane, H

    2008-01-01

    Using improved experimentally based $X{}^1\\Sigma^+$ and $a{}^3\\Sigma^+$ molecular potentials of NaRb, published recently by Pashov {\\it et al.} [Phys. Rev. A {\\bf 72}, 062505 (2005)], we apply the variable phase method to compute new data for low energy scattering of $^{23}$Na atoms by $^{85}$Rb atoms and $^{87}$Rb atoms. These are scattering lengths and volumes, numbers of bound states and effective ranges. From an analysis of the contributions of s-wave and p-wave scatterings to the elastic cross section we estimate temperatures below which only s-wave scattering is dominant. We supply evidence for the existence of a near zero energy p-wave bound state supported by the singlet molecular potential.

  8. Cyclotron trap: future experiments

    The cyclotron trap at PSI was built to increase the brightness of a source of x-rays emitted from exotic atoms. It allows to work at target densities where the interaction with the surrounding atoms is substantially reduced. Especially electron refilling can be excluded for medium to low Z atoms, which results in a high or even complete ionization. X-rays emitted from higher n-states of electron-free exotic atoms have well defined energies with the error originating only from the error in the mass values of the constituent particles. In consequence an experiment for a new determination of the pion mass was performed using a high resolution crystal spectrometer. The determination of the response function of the spectrometer could be performed using x-rays from completely ionized pionic carbon and with a dedicated electron cyclotron resonance ion trap (ECRIT). A further extension of the ECRIT method allows a direct calibration of exotic atom transitions as well as a precise determination of the energy of fluorescence lines. In combination an increase in accuracy of one order of magnitude can be achieved and a dense set of x-ray energy standards below 20 keV can be established. (author)

  9. Characterization of a magnetic trap by polarization dependent Zeeman spectroscopy

    Nielsen, Carsten Vandel; Lyngsøe, Jens Kristian; Thorseth, Anders;

    2008-01-01

    This paper demonstrates a detailed experimental study of our cloverleaf magnetic trap for sodium atoms. By using polarization dependent Zeeman spectroscopy of our atomic beam, passing the magnetic trap region, we have determined important trap parameters such as gradients, their curvatures and...

  10. Adjustable multiple sub-Doppler traps in an asymmetric magneto-optical trap

    We have realized adjustable multiple sub-Doppler traps (SDT's) in a six-beam magneto-optical trap (MOT) under asymmetric trap conditions. In the simplest case, one obtains an array of three SDT's, one usual trap at the origin and two additional traps symmetrically but oppositely located at equal and controllable distances from the origin, in good agreement with theoretical calculations. The easily adjustable array of SDT's readily available in the asymmetric MOT may open the possibility of novel atom optics or quantum optics experiments such as atom interferometer or quantum information

  11. Quantitative atomic spectroscopy for primary thermometry

    Quantitative spectroscopy has been used to measure accurately the Doppler broadening of atomic transitions in 85Rb vapor. By using a conventional platinum resistance thermometer and the Doppler thermometry technique, we were able to determine kB with a relative uncertainty of 4.1x10-4 and with a deviation of 2.7x10-4 from the expected value. Our experiment, using an effusive vapor, departs significantly from other Doppler-broadened thermometry (DBT) techniques, which rely on weakly absorbing molecules in a diffusive regime. In these circumstances, very different systematic effects such as magnetic sensitivity and optical pumping are dominant. Using the model developed recently by Stace and Luiten, we estimate the perturbation due to optical pumping of the measured kB value was less than 4x10-6. The effects of optical pumping on atomic and molecular DBT experiments is mapped over a wide range of beam size and saturation intensity, indicating possible avenues for improvement. We also compare the line-broadening mechanisms, windows of operation and detection limits of some recent DBT experiments.

  12. Quantitative atomic spectroscopy for primary thermometry

    Truong, Gar-Wing; Stace, Thomas M; Luiten, Andre N

    2010-01-01

    Quantitative spectroscopy has been used to measure accurately the Doppler-broadening of atomic transitions in $^{85}$Rb vapor. By using a conventional platinum resistance thermometer and the Doppler thermometry technique, we were able to determine $k_B$ with a relative uncertainty of $4.1\\times 10^{-4}$, and with a deviation of $2.7\\times 10^{-4}$ from the expected value. Our experiment, using an effusive vapour, departs significantly from other Doppler-broadened thermometry (DBT) techniques, which rely on weakly absorbing molecules in a diffusive regime. In these circumstances, very different systematic effects such as magnetic sensitivity and optical pumping are dominant. Using the model developed recently by Stace and Luiten, we estimate the perturbation due to optical pumping of the measured $k_B$ value was less than $4\\times 10^{-6}$. The effects of optical pumping on atomic and molecular DBT experiments is mapped over a wide range of beam size and saturation intensity, indicating possible avenues for im...

  13. 亚微米局域空心光束的产生及其在单原子囚禁与冷却中的应用理论研究∗%Theoretical research on the generation of a submicron lo calized hollow b eam and its applications in the trapping and co oling of a single atom

    任瑞敏; 尹亚玲; 王志章; 郭超修; 印建平

    2016-01-01

    In order to generate a submicron localized hollow laser beam and realize the more efficient laser cooling and trapping of a single atom, a simple and promising scheme with using the system of a single mode fiber a circle binary phase plate and a microlens is proposed in this paper. From Rayleigh-Sommerfeld diffraction theory, the intensity distribution of the generated localized hollow laser beam near the focal plane and its propagating properties in free space are calculated. Also, the dependences of the dark-spot size of the localized hollow beam on the mode radius of single mode fiber and the focal length of the mocrolens are studied. The calculated results show that the intensity distribution of the localized hollow beam presents approximately symmstrical distribution near the focal plane. In the center of the focal plane, the light intensity is 0 and increases gradually around it. So a closed spherical light field (i.e., localized hollow laser beam) with a radius of 0.4 µm is generated. The calculated results also show that the dark-spot size of the localized hollow laser beam decreases with the increasing of the microlens focal length and the decreasing of the single mode fiber mode radius. So proper parameters of this optical system can be chosen to generate localized hollow laser beams with different sizes for various applications. When the localized hollow laser beam is blue detuned, atoms will be trapped in the minimum light filed. If a repumping laser beam is applied, the trapped atoms will be also cooled by the intensity-gradient Sisyphus cooling. In this paper, we build a device for trapping and cooling a single atom by using the generated blue detuned submicron localized hollow laser beam. We study the dynamical process of intensity-gradient cooling of a single 87Rb atom trapped in the localized hollow beam by Monte-Carlo method. Our study shows that a single 87Rb atom with a temperature of 120 µK (the corresponding momentum is 30~k) from a magneto

  14. Atomic Pt and molecular H2O adsorptions on SrTiO3 with and without Nb-doping: Electron trapping center and mediating roles of Pt in charge transfer from semiconductor to water

    H2O adsorption on SrO-terminated SrTiO3 (0 0 1) surface has been investigated with the first-principles calculation based on DFT. An energy barrier of 0.221 eV for H2O dissociation is obtained, which illustrates a spontaneous dissociation. H and O atoms on the SrO-termination of (0 0 1) surface recombine readily. It demonstrates that Pt induces surface dipole moment and changes the surface work function. Adsorption of atomic Pt on SrO-termination of Nb-doped SrTiO3 (0 0 1) surface indicates charge transfer from the surface to Pt, i.e., Pt is negatively charged. Fukui functions illustrate the role Pt played in mediating charge transfer from (0 0 1) surface to targets adsorbed on Pt. H2O adsorption on the Pt atom supported on Nb-doped SrTiO3 confirms the charge transfer from semiconductor containing electrons to target species, which is mediated by metal. Charge transfer from negatively charged Pt to H2O weakens (activates) the H–O bonds in molecule H2O. - Graphical abstract: Pt mediates the charge transfer from SrTiO3 to H2O and can improve the efficiency of photocatalytic water splitting. Highlights: ► Pt atom is adsorbed over an O atom on the SrTiO3 (0 0 1) surface. ► H2O is dissociatively adsorbed on the surface; and H and O readily recombine as OH. ► Pt plays as electron trapping center on SrTiO3 (0 0 1) surface. Pt mediates the charge transfer from electron-doped SrTiO3 to H2O. ► Photogenerated carriers can be effectively separated due to deposited Pt.

  15. Integrated magneto-optical traps on a chip

    Pollock, S.; Cotter, J. P.; Laliotis, A.; Hinds, E. A.

    2009-01-01

    We have integrated magneto-optical traps (MOTs) into an atom chip by etching pyramids into a silicon wafer. These have been used to trap atoms on the chip, directly from a room temperature vapor of rubidium. This new atom trapping method provides a simple way to integrate several atom sources on the same chip. It represents a substantial advance in atom chip technology and offers new possibilities for atom chip applications such as integrated single atom or photon sources and molecules on a c...

  16. Active Stabilization of Ion Trap Radiofrequency Potentials

    Johnson, K G; Neyenhuis, B; Mizrahi, J; Monroe, C

    2016-01-01

    We actively stabilize the harmonic oscillation frequency of a laser-cooled atomic ion confined in a rf Paul trap by sampling and rectifying the high voltage rf applied to the trap electrodes. We are able to stabilize the 1 MHz atomic oscillation frequency to better than 10 Hz, or 10 ppm. This represents a suppression of ambient noise on the rf circuit by 34 dB. This technique could impact the sensitivity of ion trap mass spectrometry and the fidelity of quantum operations in ion trap quantum information applications.

  17. Antihydrogen and mirror-trapped antiproton discrimination: Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap

    Amole, C.; Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.; Bertsche, W.; Butler, E.; Cesar, C. L.; S. Chapman; Charlton, M.; Deller, A.; Eriksson, S.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.

    2012-01-01

    Recently, antihydrogen atoms were trapped at CERN in a magnetic minimum (minimum-B) trap formed by superconducting octupole and mirror magnet coils. The trapped antiatoms were detected by rapidly turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. Once released, these antiatoms quickly hit the trap wall, whereupon the positrons and antiprotons in the antiatoms annihilated. The antiproton annihilations produce easily detected s...

  18. Direct frequency comb laser cooling and trapping

    Jayich, A M; Campbell, W C

    2016-01-01

    Continuous wave (CW) lasers are the enabling technology for producing ultracold atoms and molecules through laser cooling and trapping. The resulting pristine samples of slow moving particles are the de facto starting point for both fundamental and applied science when a highly-controlled quantum system is required. Laser cooled atoms have recently led to major advances in quantum information, the search to understand dark energy, quantum chemistry, and quantum sensors. However, CW laser technology currently limits laser cooling and trapping to special types of elements that do not include highly abundant and chemically relevant atoms such as hydrogen, carbon, oxygen, and nitrogen. Here, we demonstrate that Doppler cooling and trapping by optical frequency combs may provide a route to trapped, ultracold atoms whose spectra are not amenable to CW lasers. We laser cool a gas of atoms by driving a two-photon transition with an optical frequency comb, an efficient process to which every comb tooth coherently cont...

  19. Enhancing the Effect of Lorentz Invariance and Einstein's Equivalence Principle Violation in Nuclei and Atoms.

    Flambaum, V V

    2016-08-12

    Local Lorentz invariance violating (LLIV) and Einstein equivalence principle violating (EEPV) effects in atomic experiments are discussed. The EEPV effects are strongly enhanced in the narrow 7.8 eV transition in the _{90}^{229}Th nucleus. The nuclear LLIV tensors describing the anisotropy in the maximal attainable speed for massive particles (analog of the Michelson-Morley experiment for light) are expressed in terms of the experimental values of the nuclear quadrupole moments. Calculations for nuclei of experimental interest _{55}^{133}Cs, _{37}^{85}Rb, _{37}^{87}Rb, _{80}^{201}Hg, _{54}^{131}Xe, and _{10}^{21}Ne are performed. The results for _{10}^{21}Ne are used to improve the limits on the proton LLIV interaction constants by 4 orders of magnitude. PMID:27563955

  20. Dichroic atomic vapor laser lock with multi-gigahertz stabilization range

    Pustelny, S; Sholtes, T; Budker, D

    2015-01-01

    A dichroic atomic vapor laser lock (DAVLL) system exploiting buffer-gas-filled millimeter-scale vapor cells is presented. This system offers similar stability as achievable with bulk vapor cells, but has several important advantages. In addition to its compactness, it may provide continuous stabilization in a multi-gigahertz range around the optical transition. This range may be controlled either by changing the temperature of the vapor or by application of a buffer gas under an appropriate pressure. In particular, we show that the DAVLL system with a buffer-gas cell enables locking the laser frequency between two hyperfine components of the $^{85}$Rb ground state or as far as 16 GHz away from the closest optical transition.

  1. Dichroic atomic vapor laser lock with multi-gigahertz stabilization range

    Pustelny, S.; Schultze, V.; Scholtes, T.; Budker, D.

    2016-06-01

    A dichroic atomic vapor laser lock (DAVLL) system exploiting buffer-gas-filled millimeter-scale vapor cells is presented. This system offers similar stability as achievable with conventional DAVLL system using bulk vapor cells, but has several important advantages. In addition to its compactness, it may provide continuous stabilization in a multi-gigahertz range around the optical transition. This range may be controlled either by changing the temperature of the vapor or by application of a buffer gas under an appropriate pressure. In particular, we experimentally demonstrate the ability of the system to lock the laser frequency between two hyperfine components of the 85Rb ground state or as far as 16 GHz away from the closest optical transition.

  2. Atomic approaches in metastable antiprotonic helium atoms. REPLY to 'analysis of the lifetimes and fractions of antiprotons trapped in metastable antiprotonic-helium states' by I. Shimamura and M. Kimura

    In the present note the authors clarify the purpose of YO and complement its essential points, thus showing that the criticisms of SK are inappropriate. The paper YO [1] was aimed at discussing some new aspects related to the metastability of hadronic helium atoms which had been discovered when negative kaons [2], negative pions [3] and antiprotons [4] were stopped in liquid helium. The delayed fraction, time spectrum shape and lifetimes were the observables. Further experimental studies are in progress [5], and as of today there is no successful explanation for these interesting phenomena. So, YO tried to give brief and rather qualitative estimates for the observations in an intuitive way, considering only the leading terms. The following problems are discussed in as simple a manner as possible, starting from the exotic-atom viewpoints of Condo [6] and Russell [7]: i)the atomic core polarization effect, ii)the structure and radiative lifetimes, iii)the non-statistical distribution of the angular momentum and an estimate of the delayed fraction, and iv)the isotope effect, though the title represents only i). To respond to the comments of SK, it is important to consider the correspondence between the atomic approach and the molecular approach for the metastable antiprotonic helium atom of Condo-Russell. We therefore begin this note with a discussion of this aspect. (author)

  3. Experimental investigation of planar ion traps

    Pearson, C E; Brown, K R; Chuang, I L; Leibrandt, D R; Mallard, W J

    2005-01-01

    Chiaverini et al. [Quant. Inf. Comput. 5, 419 (2005)] recently suggested a linear Paul trap geometry for ion trap quantum computation that places all of the electrodes in a plane. Such planar ion traps are compatible with modern semiconductor fabrication techniques and can be scaled to make compact, many zone traps. In this paper we present an experimental realization of planar ion traps using electrodes on a printed circuit board to trap linear chains of tens of 0.44 micron diameter charged particles in a vacuum of 15 Pa (0.1 torr). With these traps we address concerns about the low trap depth of planar ion traps and develop control electrode layouts for moving ions between trap zones without facing some of the technical difficulties involved in an atomic ion trap experiment. Specifically, we use a trap with 36 zones (77 electrodes) arranged in a cross to demonstrate loading from a traditional four rod linear Paul trap, linear ion movement, splitting and joining of ion chains, and movement of ions through in...

  4. Inhibition of Coherence in Trapped Bose-Einstein Condensates

    We analyze the dependence of the collapse and revival of many-atom coherence of a trapped Bose-Einstein condensate on the trap potential, dimensionality of the gas, and atom number fluctuations. We show that in a class of experimentally relevant systems the collapse time vanishes in the limit of a large number of atoms, implying that the trapped Bose gas cannot sustain a well-defined quantum phase. copyright 1997 The American Physical Society

  5. Efficient, Tightly-Confined Trapping of 226Ra

    Parker, R H; Bailey, K; Greene, J P; Holt, R J; Kalita, M R; Korsch, W; Lu, Z -T; Mueller, P; O'Connor, T P; Singh, J; Sulai, I A; Trimble, W L

    2013-01-01

    We demonstrate a technique for transferring $^{226}$Ra atoms from a 3-dimensional magneto-optical-trap (MOT) into a standing wave optical dipole trap (ODT) in an adjacent chamber. The resulting small trapping volume (120 $\\mu$m in diameter) allows for high control of the electric and magnetic fields applied to the atoms. The atoms are first transferred to a traveling-wave optical dipole trap, which is then translated 46 cm to a science chamber. The atoms are subsequently transferred into an orthogonal standing-wave ODT by application of a 1-dimensional MOT along the traveling-wave axis. For each stage, transfer efficiencies exceeding 60% are demonstrated.

  6. Flow injection determination of selenium by successive retention of Se(IV) and tetrahydroborate(III) on an anion-exchange resin and hydride generation electrothermal atomization atomic absorption spectrometry with in-atomizer trapping. Part 1. Method development and investigation of interferences

    Carrero, Pablo E.; Tyson, Julian F.

    1998-12-01

    A sample solution was passed at 20 ml min -1 through a column (150×4 mm 2) of Amberlite IRA-410Stron anion-exchange resin for 60 s. After washing, a solution of 0.1% sodium borohydride was passed through the column for 60 s at 5.1 ml min -1. Following a second wash, a solution of 8 mol l -1 hydrochloric acid was passed at 5.1 ml min -1 for 45 s. The hydrogen selenide was stripped from the eluent solution by the addition of an argon flow at 150 ml min -1 and the bulk phases were separated by a glass gas-liquid separator containing glass beads. The gas stream was dried by passing through a Nafion® dryer and fed, via a quartz capillary tube, into the dosing hole of a transversely heated graphite cuvette containing an integrated L'vov platform which had been pretreated with 120 μg of iridium as trapping agent. The furnace was held at a temperature of 250°C during this trapping stage and then stepped to 2000°C for atomization. The calibration was performed with aqueous standards solution of selenium (selenite, SeO 32-) with quantification by peak area. A number of experimental parameters, including reagent flow rates and composition., nature of the gas-liquid separator, nature of the anion-exchange resin, column dimensions, argon flow rate and sample pH, were optimized. The effects of a number of possible interferents, both anionic and cationic were studies for a solution of 500 ng 1 -1 of selenium. The most severe depressions were caused by iron (III) and mercury (II) for which concentrations of 20 and 10 mg 1 -1 caused a 5% depression on the selenium signal. For the other cations (cadmium, cobalt, copper, lead,. magnesium, and nickel) concentrations of 50-70 mg 1 -1 could be tolerated. Arsenate interfered at a concentration of 3 mg -1, whereas concentrations of chloride, bromide, iodide, perchlorate, and sulfate of 500-900 mg l -1 could be tolerated. A linear response was obtained between the detection limit of 4 ng 1 -1, with a characteristic mass of 130 pg. The

  7. Bose-Einstein Condensation in an electro-pneumatically transformed quadrupole-Ioffe magnetic trap

    Kumar, Sunil; Verma, Gunjan; Vishwakarma, Chetan; Noaman, Md; Rapol, Umakant

    2014-01-01

    We report a novel approach for preparing a Bose-Einstein condensate (BEC) of $^{87}$Rb atoms using electro-pneumatically driven transfer of atoms into a Quadrupole-Ioffe magnetic trap (QUIC Trap). More than 5$\\times$$10^{8}$ atoms from a Magneto-optical trap are loaded into a spherical quadrupole trap and then these atoms are transferred into an Ioffe trap by moving the Ioffe coil towards the center of the quadrupole coil, thereby, changing the distance between quadrupole trap center and the Ioffe coil. The transfer efficiency is more than 80 \\%. This approach is different from a conventional approach of loading the atoms into a QUIC trap wherein the spherical quadrupole trap is transformed into a QUIC trap by changing the currents in the quadrupole and the Ioffe coils. The phase space density is then increased by forced rf evaporative cooling to achieve the Bose-Einstein condensation having more than $10^{5}$ atoms.

  8. Low-temperature radiolysis of glycerol-1-phosphate. 1. The role of trapped and dry electrons, hydrogen atoms and hydroxyl radicals in glycerol-1-phosphate degradation

    Under a comparative investigation into the behaviour of H and OH, stabilized at 77 K, in glass-like solutions of 6 mole/l of H3PO4 and 6 mol/l of H3PO4 + 0.1 mol/l of glycerol-1-phosphate (GP) during post-irradiation period (from 2 hours to a year) and under thermal annealing of samples produced within 105-130 K interval, using ESR method, it is ascertained that primary GP radicals are produced at the expense of H and Oh H-C bond attack in all the three carbon atoms. Dry and stabilized electrons do not react with GP during irradiation. (author)

  9. An Optical Trap for Collisional Studies on Cold Fermionic Potassium

    Roati, G; Simoni, A; Modugno, G; Inguscio, M

    2000-01-01

    We report on trapping of fermionic 40K atoms in a red-detuned standing-wave optical trap, loaded from a magneto-optical trap. Typically, 10^6 atoms are loaded at a density of 10^12 cm^-3 and a temperature of 65 microK, and trapped for more than 1 s. The optical trap appears to be the proper environment for performing collisional measurements on the cold atomic sample. In particular we measure the elastic collisional rate by detecting the rethermalization following an intentional parametric heating of the atomic sample. We also measure the inelastic two-body collisional rates for unpolarized atoms in the ground hyperfine states, through detection of trap losses.

  10. Development, Fabrication and Characterisation of Atom Chips

    Groth, Sönke

    2006-01-01

    Atom chips are robust and extremely powerful toolboxes for quantum optical experiments, since they make it possible to create exceedingly precise magnetic traps for neutral atoms with minimal field modulations. Accurate manipulation of trapped atoms is feasible with magnetic and electric fields created on the atom chip. Therefore atom chips with high quality surfaces and extremely well defined wires were build (roughness < 20nm). Furthermore new generations of atom chips were developed, like ...

  11. Production and Trapping of Ultracold Polar Molecules

    David, DeMille [Yale Univ., New Haven, CT (United States)

    2015-04-21

    We report a set of experiments aimed at the production and trapping of ultracold polar molecules. We begin with samples of laser-cooled and trapped Rb and Cs atoms, and bind them together to form polar RbCs molecules. The binding is accomplished via photoassociation, which uses a laser to catalyze the sticking process. We report results from investigation of a new pathway for photoassociation that can produce molecules in their absolute ground state of vibrational and rotational motion. We also report preliminary observations of collisions between these ground-state molecules and co-trapped atoms.

  12. Efficient magneto-optical trapping of a metastable helium gas

    Pereira Dos Santos, F.; Perales, F.; Léonard, J.; Sinatra, A.; Wang, J.; Pavone, F. S.; Rasel, E.; Unnikrishnan, C. S.; Leduc, M.

    2001-04-01

    This article presents a new experiment aiming at BEC of metastable helium atoms. It describes the design of a high flux discharge source of atoms and a robust laser system using a DBR diode coupled with a high power Yb doped fiber amplifier for manipulating the beam of metastable atoms. The atoms are trapped in a small quartz cell in an extreme high vacuum. The trapping design uses an additional laser (repumper) and allows the capture of a large number of metastable helium atoms (approximately 10^9) in a geometry favorable for loading a tight magnetostatic trap.

  13. EIT resonance features in strong magnetic fields in rubidium atomic columns with length varying by 4 orders

    Mirzoyan, R.; Sargsyan, A.; Sarkisyan, D.; Wojciechowski, A.; Stabrawa, A.; Gawlik, W.

    2016-06-01

    Electromagnetically induced transparency (EIT) resonances are investigated with the 85Rb D 1 line (795 nm) in strong magnetic fields (up to 2 kG) with three different types of spectroscopic vapor cells: the nano-cell with a thickness along the direction of laser light L ≈ 795 nm, the micro-cell with L = 30 μm with the addition of a neon buffer gas, and the centimeter-long glass cell. These cells allowed us to observe systematic changes of the EIT spectra when the increasing magnetic field systematically decoupled the total atomic electron and nuclear angular moments (the Paschen-Back/Back-Goudsmit effects). The observations agree well with a theoretical model. The advantages and disadvantages of a particular type of cell are discussed along with the possible practical applications.

  14. Test of Equivalence Principle at 10(-8) Level by a Dual-Species Double-Diffraction Raman Atom Interferometer.

    Zhou, Lin; Long, Shitong; Tang, Biao; Chen, Xi; Gao, Fen; Peng, Wencui; Duan, Weitao; Zhong, Jiaqi; Xiong, Zongyuan; Wang, Jin; Zhang, Yuanzhong; Zhan, Mingsheng

    2015-07-01

    We report an improved test of the weak equivalence principle by using a simultaneous 85Rb-87Rb dual-species atom interferometer. We propose and implement a four-wave double-diffraction Raman transition scheme for the interferometer, and demonstrate its ability in suppressing common-mode phase noise of Raman lasers after their frequencies and intensity ratios are optimized. The statistical uncertainty of the experimental data for Eötvös parameter η is 0.8×10(-8) at 3200 s. With various systematic errors corrected, the final value is η=(2.8±3.0)×10(-8). The major uncertainty is attributed to the Coriolis effect. PMID:26182096

  15. Test of Equivalence Principle at $10^{-8}$ Level by a Dual-species Double-diffraction Raman Atom Interferometer

    Zhou, Lin; Tang, Biao; Chen, Xi; Gao, Fen; Peng, Wencui; Duan, Weitao; Zhong, Jiaqi; Xiong, Zongyuan; Wang, Jin; Zhang, Yuanzhong; Zhan, Mingsheng

    2015-01-01

    We report an improved test of the weak equivalence principle by using a simultaneous $^{85}$Rb-$^{87}$Rb dual-species atom interferometer. We propose and implement a four-wave double-diffraction Raman transition scheme for the interferometer, and demonstrate its ability in suppressing common-mode phase noise of Raman lasers after their frequencies and intensity ratios are optimized. The statistical uncertainty of the experimental data for E\\"{o}tv\\"{o}s parameter $\\eta$ is $0.8\\times10^{-8}$ at 3200 s. With various systematic errors corrected the final value is $\\eta=(2.8\\pm3.0)\\times10^{-8}$. The major uncertainty is attributed to the Coriolis effect.

  16. Generation of non-classical correlated photon pairs via a ladder-type atomic configuration: theory and experiment.

    Ding, Dong-Sheng; Zhou, Zhi-Yuan; Shi, Bao-Sen; Zou, Xu-Bo; Guo, Guang-Can

    2012-05-01

    We experimentally generate a non-classical correlated two-color photon pair at 780 and 1529.4 nm in a ladder-type configuration using a hot 85Rb atomic vapor with the production rate of ~10(7)/s. The non-classical correlation between these two photons is demonstrated by strong violation of Cauchy-Schwarz inequality by the factor R = 48 ± 12. Besides, we experimentally investigate the relations between the correlation and some important experimental parameters such as the single-photon detuning, the powers of pumps. We also make a theoretical analysis in detail and the theoretical predictions are in reasonable agreement with our experimental results. PMID:22565763

  17. Doppler cooling and trapping on forbidden transitions

    Binnewies, T; Sterr, U; Riehle, F; Helmcke, J; Mehlstäubler, T E; Rasel, E M; Ertmer, W

    2001-01-01

    Ultracold atoms at temperatures close to the recoil limit have been achieved by extending Doppler cooling to forbidden transitions. A cloud of ^40Ca atoms has been cooled and trapped to a temperature as low as 6 \\mu K by operating a magneto-optical trap on the spin-forbidden intercombination transition. Quenching the long-lived excited state with an additional laser enhanced the scattering rate by a factor of 15, while a high selectivity in velocity was preserved. With this method more than 10% of pre-cooled atoms from a standard magneto-optical trap have been transferred to the ultracold trap. Monte-Carlo simulations of the cooling process are in good agreement with the experiments.

  18. Doppler cooling and trapping on forbidden transitions.

    Binnewies, T; Wilpers, G; Sterr, U; Riehle, F; Helmcke, J; Mehlstäubler, T E; Rasel, E M; Ertmer, W

    2001-09-17

    Ultracold atoms at temperatures close to the recoil limit have been achieved by extending Doppler cooling to forbidden transitions. A cloud of (40)Ca atoms has been cooled and trapped to a temperature as low as 6 microK by operating a magnetooptical trap on the spin-forbidden intercombination transition. Quenching the long-lived excited state with an additional laser enhanced the scattering rate by a factor of 15, while a high selectivity in velocity was preserved. With this method, more than 10% of precooled atoms from a standard magnetooptical trap have been transferred to the ultracold trap. Monte Carlo simulations of the cooling process are in good agreement with the experiments. PMID:11580503

  19. A cold 87Rb atomic beam

    Wang Xiao-Jia; Feng Yan-Ying; Xue Hong-Bo; Zhou Zhao-Ying; Zhang Wen-Dong

    2011-01-01

    We demonstrate an experimental setup for the production of a beam source of cold 87Rb atoms.The atoms are extracted from a trapped cold atomic cloud in an unbalanced three-dimensional magneto-optical trap.Via a radiation pressure difference generated by a specially designed leak tunnel along one trapping laser beam,the atoms are pushed out continuously with low velocities and a high flux.The most-probable velocity in the beam is varied from 9 m/s to 19 m/s by varying the detuning of the trapping laser beams in the magneto-optical trap and the flux can be tuned up to 4× 109 s-1 by increasing the intensity of the trapping beams.We also present a simple model for describing the dependence of the beam performance on the magneto-optical trap trapping laser intensity and the detuning.

  20. Precision measurement of a trapping potential for an ultracold gas

    Parametric excitation of ultracold atomic gases in optical dipole traps strongly depends on the trap anharmonicity. For non-interacting gases, the anharmonicity prevents energy input beyond certain level. We use this as a basis for precision measurement of trap parameters. The frequencies and depth are derived from comparison of the excitation spectrum to models, where the anharmonicity is treated non-perturbatively. Measurements are done for both quantum and classical motion of trapped atoms. For the classical motion, the validity of the model is crosschecked in an independent experiment. - Highlights: • Parametric excitation of ultracold atoms in optical dipole traps is strongly dependent on the trap anharmonicity. • The anharmonicity prevents energy input beyond certain level. • This energy-input saturation is used for precision measurement of trap parameters