A waveguide frequency converter connecting rubidium-based quantum memories to the telecom C-band.

PubMed

Albrecht, Boris; Farrera, Pau; Fernandez-Gonzalvo, Xavier; Cristiani, Matteo; de Riedmatten, Hugues

2014-02-27

Coherently converting the frequency and temporal waveform of single and entangled photons will be crucial to interconnect the various elements of future quantum information networks. Of particular importance is the quantum frequency conversion of photons emitted by material systems able to store quantum information, so-called quantum memories. There have been significant efforts to implement quantum frequency conversion using nonlinear crystals, with non-classical light from broadband photon-pair sources and solid-state emitters. However, solid state quantum frequency conversion has not yet been achieved with long-lived optical quantum memories. Here we demonstrate an ultra-low-noise solid state photonic quantum interface suitable for connecting quantum memories based on atomic ensembles to the telecommunication fibre network. The interface is based on an integrated-waveguide nonlinear device. We convert heralded single photons at 780 nm from a rubidium-based quantum memory to the telecommunication wavelength of 1,552 nm, showing significant non-classical correlations between the converted photon and the heralding signal.

Experimental Raman adiabatic transfer of optical states in rubidium

NASA Astrophysics Data System (ADS)

Appel, Jürgen; Figueroa, Eden; Vewinger, Frank; Marzlin, Karl-Peter; Lvovsky, Alexander

2007-06-01

An essential element of a quantum optical communication network is a tool for transferring and/or distributing quantum information between optical modes (possibly of different frequencies) in a loss- and decoherence-free fashion. We present a theory [1] and an experimental demonstration [2] of a protocol for routing and frequency conversion of optical quantum information via electromagnetically-induced transparency in an atomic system with multiple excited levels. Transfer of optical states between different signal modes is implemented by adiabatically changing the control fields. The proof-of-principle experiment is performed using the hyperfine levels of the rubidium D1 line. [1] F. Vewinger, J. Appel, E. Figueroa, A. I. Lvovsky, quant-ph/0611181 [2] J. Appel, K.-P. Marzlin, A. I. Lvovsky, Phys. Rev. A 73, 013804 (2006)

Theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency

NASA Astrophysics Data System (ADS)

Liu, Yang; Li, Shu-qing; Feng, Zhong-ying; Liu, Xiao-fei; Gao, Jin-yue

2016-12-01

To obtain the weak signal light detection from the high background noise, we present a theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency. In a three-level Λ -type atomic system in the rubidium D1 line, the bandwidth of the EIT atomic filter is narrowed to ~6.5 \\text{MHz} . And the single peak transmission of the filter can be up to 86% . Moreover, the transmission wavelength can be tuned by changing the coupling light frequency. This theoretical scheme can also be applied to other alkali atomic systems.

Two-photon Direct Frequency Comb Spectroscopy of Alkali Atoms

NASA Astrophysics Data System (ADS)

Nguyen, Khoa; Pradhananga, Trinity; Palm, Christopher; Stalnaker, Jason; Kimball, Derek Jackson

2012-06-01

We are using direct frequency comb spectroscopy to study transition frequencies and excited state hyperfine structure in potassium and rubidium using 2-photon transitions excited directly with the frequency-doubled output of a erbium fiber optical frequency comb. The frequency comb output is directed in two counterpropagating directions through a vapor cell containing the atomic vapor of interest. A pair of optical filters is used to select teeth of the comb in order to identify the transition wavelengths. A photomultiplier tube (PMT) measures fluorescence from a decay channel wavelength selected with another optical filter. Using different combinations of filters enables a wide range of transitions to be investigated. By scanning the repetition rate, a Doppler-free spectrum can be obtained enabling kHz-resolution spectral measurements. The thermal motion of the atoms in the vapor cell actually eliminates the need to fine-tune the offset frequency and repetition rate, alleviating a somewhat challenging requirement for spectroscopy of cold atoms. Our investigations are laying the groundwork for a long-term research program to use direct frequency comb spectroscopy to understand the complex spectra of rare-earth atoms.

Direct Frequency Comb Spectroscopy of Alkali Atoms

NASA Astrophysics Data System (ADS)

Pradhananga, Trinity; Palm, Christopher; Nguyen, Khoa; Guttikonda, Srikanth; Kimball, Derek Jackson

2011-11-01

We are using direct frequency comb spectroscopy to study transition frequencies and excited state hyperfine structure in potassium and rubidium using 2-photon transitions excited directly with the frequency-doubled output of a erbium fiber optical frequency comb. The frequency comb output is directed in two counterpropagating directions through a vapor cell containing the atomic vapor of interest. A pair of optical filters is used to select teeth of the comb in order to identify the transition wavelengths. A photomultiplier tube (PMT) measures fluorescence from a decay channel wavelength selected with another optical filter. Using different combinations of filters enables a wide range of transitions to be investigated. By scanning the repetition rate, a Doppler-free spectrum can be obtained enabling kHz-resolution spectral measurements. The thermal motion of the atoms in the vapor cell actually eliminates the need to fine-tune the offset frequency and repetition rate, alleviating a somewhat challenging requirement for spectroscopy of cold atoms. Our investigations are laying the groundwork for a long-term research program to use direct frequency comb spectroscopy to understand the complex spectra of rare-earth atoms.

Frequency-Comb Based Double-Quantum Two-Dimensional Spectrum Identifies Collective Hyperfine Resonances in Atomic Vapor Induced by Dipole-Dipole Interactions

NASA Astrophysics Data System (ADS)

Lomsadze, Bachana; Cundiff, Steven T.

2018-06-01

Frequency-comb based multidimensional coherent spectroscopy is a novel optical method that enables high-resolution measurement in a short acquisition time. The method's resolution makes multidimensional coherent spectroscopy relevant for atomic systems that have narrow resonances. We use double-quantum multidimensional coherent spectroscopy to reveal collective hyperfine resonances in rubidium vapor at 100 °C induced by dipole-dipole interactions. We observe tilted and elongated line shapes in the double-quantum 2D spectra, which have never been reported for Doppler-broadened systems. The elongated line shapes suggest that the signal is predominately from the interacting atoms that have a near zero relative velocity.

Transmission degradation and preservation for tapered optical fibers in rubidium vapor.

PubMed

Lai, Meimei; Franson, James D; Pittman, Todd B

2013-04-20

The use of subwavelength diameter tapered optical fibers (TOFs) in warm rubidium vapor has recently been identified as a promising system for realizing ultralow-power nonlinear optical effects. However, at the relatively high atomic densities needed for many of these experiments, rubidium atoms accumulating on the TOF surface can cause a significant loss of overall transmission through the fiber. Here we report direct measurements of the time scale associated with this transmission degradation for various rubidium density conditions. Transmission is affected almost immediately after the introduction of rubidium vapor into the system, and declines rapidly as the density is increased. More significantly, we show how a heating element designed to raise the TOF temperature can be used to reduce this transmission loss and dramatically extend the effective TOF transmission lifetime.

Efficient frequency doubler of 1560 nm laser based on a semi-monolithic resonant cavity with a PPKTP crystal

NASA Astrophysics Data System (ADS)

Wang, Junmin; Zhang, Kong; Ge, Yulong; Guo, Shanlong

2016-06-01

We have demonstrated 1.61 W of 780 nm single-frequency continuous-wave laser output with a semi-monolithic periodically poled potassium titanyl phosphate (PPKTP) crystal doubler pumped by a 2-W erbium-doped fiber amplifier boosted 1560 nm diode laser. The measured maximum doubling efficiency is 77%, and the practical value should be 80% when taking into account the fundamental-wave mode matching efficiency. The measured beam quality factor of 780 nm output, M2, is better than 1.04. Typical root-mean-square fluctuation of 780 nm output is less than 0.5% in 30 minutes. This compact frequency doubler has good mechanical stability, and can be employed for many applications, such as laser cooling and trapping, atomic coherent control, atomic interferometer, and quantum frequency standard with rubidium atoms.

Spectrum of spin waves in cold polarized gases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreeva, T. L., E-mail: phdocandreeva@yandex.ru

2017-02-15

The spin dynamics of cold polarized gases are investigated using the Boltzmann equation. The dispersion relation for spin waves (transverse component of the magnetic moment) and the spin diffusion coefficient of the longitudinal component of the magnetic moment are calculated without using fitting parameters. The spin wave frequency and the diffusion coefficient for rubidium atoms are estimated numerically.

Investigation of infrared radiation in rubidium vapor upon two-photon and step-by-step excitations of the initial level

NASA Astrophysics Data System (ADS)

Bimagambetov, T. S.

2011-12-01

Stimulated infrared (IR) 5.231-μm line radiation is obtained upon two-photon and step-by-step excitations of the initial level. Dependences of the line power on the concentration of atoms and laser frequency are investigated. The mechanism of initial level occupation is explained.

Nanoscale light–matter interactions in atomic cladding waveguides

PubMed Central

Stern, Liron; Desiatov, Boris; Goykhman, Ilya; Levy, Uriel

2013-01-01

Alkali vapours, such as rubidium, are being used extensively in several important fields of research such as slow and stored light nonlinear optics quantum computation, atomic clocks and magnetometers. Recently, there is a growing effort towards miniaturizing traditional centimetre-size vapour cells. Owing to the significant reduction in device dimensions, light–matter interactions are greatly enhanced, enabling new functionalities due to the low power threshold needed for nonlinear interactions. Here, taking advantage of the mature platform of silicon photonics, we construct an efficient and flexible platform for tailored light–vapour interactions on a chip. Specifically, we demonstrate light–matter interactions in an atomic cladding waveguide, consisting of a silicon nitride nano-waveguide core with a rubidium vapour cladding. We observe the efficient interaction of the electromagnetic guided mode with the rubidium cladding and show that due to the high confinement of the optical mode, the rubidium absorption saturates at powers in the nanowatt regime. PMID:23462991

Magneto-optical polarization rotation in a ladder-type atomic system for tunable offset locking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parniak, Michał, E-mail: michal.parniak@fuw.edu.pl; Leszczyński, Adam; Wasilewski, Wojciech

2016-04-18

We demonstrate an easily tunable locking scheme for stabilizing frequency-sum of two lasers on a two-photon ladder transition based on polarization rotation in warm rubidium vapors induced by magnetic field and circularly polarized drive field. Unprecedented tunability of the two-photon offset frequency is due to strong splitting and shifting of magnetic states in external field. In our experimental setup, we achieve two-photon detuning of up to 700 MHz.

Absolute frequency list of the ν3-band transitions of methane at a relative uncertainty level of 10(-11).

PubMed

Okubo, Sho; Nakayama, Hirotaka; Iwakuni, Kana; Inaba, Hajime; Sasada, Hiroyuki

2011-11-21

We determine the absolute frequencies of 56 rotation-vibration transitions of the ν(3) band of CH(4) from 88.2 to 90.5 THz with a typical uncertainty of 2 kHz corresponding to a relative uncertainty of 2.2 × 10(-11) over an average time of a few hundred seconds. Saturated absorption lines are observed using a difference-frequency-generation source and a cavity-enhanced absorption cell, and the transition frequencies are measured with a fiber-laser-based optical frequency comb referenced to a rubidium atomic clock linked to the international atomic time. The determined value of the P(7) F(2)((2)) line is consistent with the International Committee for Weights and Measures recommendation within the uncertainty. © 2011 Optical Society of America

Subpicosecond X rotations of atomic clock states

NASA Astrophysics Data System (ADS)

Song, Yunheung; Lee, Han-gyeol; Kim, Hyosub; Jo, Hanlae; Ahn, Jaewook

2018-05-01

We demonstrate subpicosecond-timescale population transfer between the pair of hyperfine ground states of atomic rubidium using a single laser-pulse. Our scheme utilizes the geometric and dynamic phases induced during Rabi oscillation through the fine-structure excited state to construct an X rotation gate for the hyperfine-state qubit system. The experiment performed with a femtosecond laser and cold rubidium atoms, in a magnetooptical trap, shows over 98% maximal population transfer between the clock states.

Measuring the Temperature of the Ithaca College MOT Cloud using a CMOS Camera

NASA Astrophysics Data System (ADS)

Smucker, Jonathan; Thompson, Bruce

2015-03-01

We present our work on measuring the temperature of Rubidium atoms cooled using a magneto-optical trap (MOT). The MOT uses laser trapping methods and Doppler cooling to trap and cool Rubidium atoms to form a cloud that is visible to a CMOS Camera. The Rubidium atoms are cooled further using optical molasses cooling after they are released from the trap (by removing the magnetic field). In order to measure the temperature of the MOT we take pictures of the cloud using a CMOS camera as it expands and calculate the temperature based on the free expansion of the cloud. Results from the experiment will be presented along with a summary of the method used.

Radiation hardness of Efratom M-100 rubidium frequency standard

NASA Technical Reports Server (NTRS)

English, T. C.; Vorwerk, H.; Rudie, N. J.

1983-01-01

The effects of nuclear radiation on rubidium gas cell frequency standards and components are presented, including the results of recent tests where a continuously operating rubidium frequency standard (Effratom, Model M-100) was subjected to simultaneous neutron/gamma radiation. At the highest neutron fluence 7.5 10 to the 12th power n/sq cm and total dose 11 krad(Si) tested, the unit operated satisfactorily; the total frequency change over the 2 1/2 hour test period due to all causes, including repeated retraction from and insertion into the reactor, was less than 1 x 10 to the -10th power. The effects of combined neutron/gamma radiation on rubidium frequency standard physics package components were also studied, and the results are presented.

Control of spontaneous emission from a microwave-field-driven four-level atom in an anisotropic photonic crystal

NASA Astrophysics Data System (ADS)

Zhang, Duo; Li, Jiahua; Ding, Chunling; Yang, Xiaoxue

2012-05-01

The spontaneous emission properties of a microwave-field-driven four-level atom embedded in anisotropic double-band photonic crystals (PCs) are investigated. We discuss the influences of the band-edge positions, Rabi frequency and detuning of the microwave field on the emission spectrum. It is found that several interesting features such as spectral-line enhancement, spectral-line suppression, spectral-line overlap, and multi-peak structures can be observed in the spectra. The proposed scheme can be achieved by use of a microwave-coupled field into hyperfine levels in rubidium atom confined in a photonic crystal. These theoretical investigations may provide more degrees of freedom to manipulate the atomic spontaneous emission.

Digital frequency control of satellite frequency standards. [Defense Navigation Satellites

NASA Technical Reports Server (NTRS)

Nichols, S. A.

1973-01-01

In the Frequency and Time Standard Development Program of the TIMATION System, a new miniaturized rubidium vapor frequency standard has been tested and analyzed for possible use on the TIMATION 3A launch, as part of the Defense Navigation Satellite Development Program. The design and construction of a digital frequency control was required to remotely control this rubidium vapor frequency standard as well as the quartz oscillator in current use. This control must be capable of accepting commands from a satellite telemetry system, verify that the correct commands have been sent and control the frequency to the requirements of the system. Several modifications must be performed to the rubidium vapor frequency standard to allow it to be compatible with the digital frequency control. These include the addition of a varactor to voltage tune the coarse range of the flywheel oscillator, and a modification to supply the C field current externally. The digital frequency control for the rubidium vapor frequency standard has been successfully tested in prototype form.

Two-Photon Absorption Spectroscopy of Rubidium with a Dual-Comb Tequnique

NASA Astrophysics Data System (ADS)

Nishiyama, Akiko; Yoshida, Satoru; Hariki, Takuya; Nakajima, Yoshiaki; Minoshima, Kaoru

2017-06-01

Dual-comb spectroscopies have great potential for high-resolution molecular and atomic spectroscopies, thanks to the broadband comb spectrum consisting of dense narrow modes. In this study, we apply the dual-comb system to Doppler-free two-photon absorption spectroscopy. The outputs of two frequency combs excite several two-photon transitions of rubidium, and we obtained broadband Doppler-free spectra from dual-comb fluorescence signals. The fluorescence detection scheme circumvents the sensitivity limit which is effectively determined by the dynamic range of photodetectors in absorption-based dual-comb spectroscopies. Our system realized high-sensitive, Doppler-free high-resolution and broadband atomic spectroscopy. A part of observed spectra of 5S_{1/2} - 5D_{5/2} transition is shown in the figure. The hyperfine structures of the F" = 1 - F' = 3,2,1 transitions are fully-resolved and the spectral widths are approximately 5 MHz. The absolute frequency axis is precisely calibrated from comb mode frequencies which were stabilized to a GPS-disciplined clock. This work was supported by JST through the ERATO MINOSHIMA Intelligent Optical Synthesizer Project and Grant-in-Aid for JSPS Fellows (16J02345). A. Nishiyama, S. Yoshida, Y. Nakajima, H. Sasada, K. Nakagawa, A. Onae, K. and Minoshima, Opt. Express 24, 25894 (2016). A. Hipke, S. A. Meek, T. Ideguchi, T.W. Hänsch, and N. Picqué, Phys. Rev. A 90, 011805(R) (2014).

United time-frequency spectroscopy for dynamics and global structure.

PubMed

Marian, Adela; Stowe, Matthew C; Lawall, John R; Felinto, Daniel; Ye, Jun

2004-12-17

Ultrashort laser pulses have thus far been used in two distinct modes. In the time domain, the pulses have allowed probing and manipulation of dynamics on a subpicosecond time scale. More recently, phase stabilization has produced optical frequency combs with absolute frequency reference across a broad bandwidth. Here we combine these two applications in a spectroscopic study of rubidium atoms. A wide-bandwidth, phase-stabilized femtosecond laser is used to monitor the real-time dynamic evolution of population transfer. Coherent pulse accumulation and quantum interference effects are observed and well modeled by theory. At the same time, the narrow linewidth of individual comb lines permits a precise and efficient determination of the global energy-level structure, providing a direct connection among the optical, terahertz, and radio-frequency domains. The mechanical action of the optical frequency comb on the atomic sample is explored and controlled, leading to precision spectroscopy with an appreciable reduction in systematic errors.

One step beyond the electric dipole approximation: An experiment to observe the 5p → 6p forbidden transition in atomic rubidium

NASA Astrophysics Data System (ADS)

Ponciano-Ojeda, F.; Hernández-Gómez, S.; Mojica-Casique, C.; Ruiz-Martínez, E.; López-Hernández, O.; Colín-Rodríguez, R.; Ramírez-Martínez, F.; Flores-Mijangos, J.; Sahagún, D.; Jáuregui, R.; Jiménez-Mier, J.

2018-01-01

An advanced undergraduate experiment to study the 5 P 3 / 2 → 6 P 3 / 2 electric quadrupole transition in rubidium atoms is presented. The experiment uses two external cavity diode lasers, one operating at the D2 rubidium resonance line and the other built with commercial parts to emit at 911 nm. The lasers produce the 5 s → 5 p → 6 p excitation sequence in which the second step is the forbidden transition. Production of atoms in the 6 P 3 / 2 state is observed by detection of the 420 nm fluorescence that results from electric dipole decay into the ground state. Lines whose widths are significantly narrower than the Doppler width are used to study the hyperfine structure of the 6 P 3 / 2 state in rubidium. The spectra illustrate characteristics unique to electric dipole forbidden transitions, like the electric quadrupole selection rules; they are also used to show general aspects of two-color laser spectroscopy such as velocity selection and hyperfine pumping.

Faraday spectroscopy of ultracold atoms guided in hollow core optical fibers

NASA Astrophysics Data System (ADS)

Fatemi, Fredrik; Pechkis, Joseph

2013-05-01

We have performed spatially and temporally resolved magnetometry using Faraday spectroscopy of ultracold rubidium atoms confined in hollow core optical fibers. We first guide 105 Rb atoms into a 3-cm-long, 100-micron-core hollow fiber using blue-detuned hollow waveguide modes. Inside the fiber, the atoms are exposed to an optical pumping pulse, and the Larmor precession is monitored by the polarization rotation of a probe laser beam detuned by 50 GHz. The intense guide beams can perturb the detected Larmor precession frequencies, but we show that by confining the atoms to the intensity null of higher order blue-detuned hollow modes, these perturbations are reduced by over 95% compared to red-detuned guides. By adjusting the guide beam detuning and polarization, the deleterious effects of both photon scattering and frequency shifts can be suppressed such that multiple magnetic field measurements with sensitivity of 30 nT per sampling pulse can be obtained throughout the length of the fiber in a single loading cycle. Work supported by ONR and DARPA.

Optical field induced rotation of polarization in rubidium atoms with the additional magnetic field

NASA Astrophysics Data System (ADS)

Ummal Momeen, M.; Hu, Jianping

2017-11-01

We present the magnetic and optical field induced rotation of polarization in 87Rb and 85Rb atoms at geophysical magnetic fields. The line shape varies considerably in the presence of a magnetic field of the order of a few mG. Multiple Zeeman sublevel EIT systems involving rubidium atoms are investigated. Theoretical formalism of optical field induced polarization rotation in the presence of a magnetic field is discussed by considering all the Zeeman sublevels. It is noted that the ground state population distribution also plays a major role.

Operational frequency stability of rubidium and cesium frequency standards

NASA Technical Reports Server (NTRS)

Lavery, J. E.

1973-01-01

The frequency stabilities under operational conditions of several commercially available rubidium and cesium frequency standards were determined from experimental data for frequency averaging times from 10 to the 7th power s and are presented in table and graph form. For frequency averaging times between 10 to the 5th power and 10 to the 7th power s, the rubidium standards tested have a stability of between 10 to the minus 12th power and 5 x 10 to the minus 12th power, while the cesium standards have a stability of between 2 x 10 to the minus 13th power and 5 x 10 to the minus 13th power.

The frequency and time standard and activities at the Beijing Institute of Radio Metrology and Measurements. [China

NASA Technical Reports Server (NTRS)

Wang, H. T.

1979-01-01

Three kinds of frequency measuring systems are described: frequency comparison, phase comparison, and time comparison. With the help of the portable cesium clock in determining the time delay between two stations, a time synchronization, experiment was conducted using the Symphonie satellite. A result with an accuracy of 30 ns and an uncertainty of about 10 ns was obtained. Another experiment, applying the television pulse technique for time synchronization, yielded a result with an error of about 0.5 mu s in 24 hours. In order to measure the short term frequency stability of crystal oscillators or other frequency sources, a rubidium maser atomic frequency standard was developed as well as a short term stability measuring system.

A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium.

PubMed

McCarron, Daniel J; Hughes, Ifan G; Tierney, Patrick; Cornish, Simon L

2007-09-01

The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D(2) transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude.

Atomic clocks and the continuous-time random-walk

NASA Astrophysics Data System (ADS)

Formichella, Valerio; Camparo, James; Tavella, Patrizia

2017-11-01

Atomic clocks play a fundamental role in many fields, most notably they generate Universal Coordinated Time and are at the heart of all global navigation satellite systems. Notwithstanding their excellent timekeeping performance, their output frequency does vary: it can display deterministic frequency drift; diverse continuous noise processes result in nonstationary clock noise (e.g., random-walk frequency noise, modelled as a Wiener process), and the clock frequency may display sudden changes (i.e., "jumps"). Typically, the clock's frequency instability is evaluated by the Allan or Hadamard variances, whose functional forms can identify the different operative noise processes. Here, we show that the Allan and Hadamard variances of a particular continuous-time random-walk, the compound Poisson process, have the same functional form as for a Wiener process with drift. The compound Poisson process, introduced as a model for observed frequency jumps, is an alternative to the Wiener process for modelling random walk frequency noise. This alternate model fits well the behavior of the rubidium clocks flying on GPS Block-IIR satellites. Further, starting from jump statistics, the model can be improved by considering a more general form of continuous-time random-walk, and this could bring new insights into the physics of atomic clocks.

3D atom microscopy in the presence of Doppler shift

NASA Astrophysics Data System (ADS)

Rahmatullah; Chuang, You-Lin; Lee, Ray-Kuang; Qamar, Sajid

2018-03-01

The interaction of hot atoms with laser fields produces a Doppler shift, which can severely affect the precise spatial measurement of an atom. We suggest an experimentally realizable scheme to address this issue in the three-dimensional position measurement of a single atom in vapors of rubidium atoms. A three-level Λ-type atom-field configuration is considered where a moving atom interacts with three orthogonal standing-wave laser fields and spatial information of the atom in 3D space is obtained via an upper-level population using a weak probe laser field. The atom moves with velocity v along the probe laser field, and due to the Doppler broadening the precision of the spatial information deteriorates significantly. It is found that via a microwave field, precision in the position measurement of a single hot rubidium atom can be attained, overcoming the limitation posed by the Doppler shift.

Proceedings of the 30th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting

NASA Technical Reports Server (NTRS)

Breakiron, Lee A. (Editor)

1999-01-01

This document is a compilation of technical papers presented at the 30th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting held 1-3 December 1998 at the Hyatt Regency Hotel at Reston Town Center, Reston, Virginia. Papers are in the following categories: 1) Recent developments in rubidium, cesium, and hydrogen-based atomic frequency standards, and in trapped-ion and space clock technology; 2) National and international applications of PTTI technology with emphasis on GPS and GLONASS timing, atomic time scales, and telecommunications; 3) Applications of PTTI technology to evolving military navigation and communication systems; geodesy; aviation; and pulsars; and 4) Dissemination of precise time and frequency by means of GPS, geosynchronous communication satellites, computer networks, WAAS, and LORAN.

Miniature Dual-Mode Absolute Scalar Magnetometer Based on the Rubidium Isotope 87Rb

NASA Astrophysics Data System (ADS)

Korth, H.; Strohbehn, K.; Kitching, J.

2016-10-01

Miniaturized absolute scalar magnetometer based on the rubidium isotope 87Rb takes advantage of recent breakthroughs in micro-fabricated atomic devices, has a total mass of 210 g and uses <1 W of power, and maintains a sensitivity of 0.1 nT rms.

Opto-Electronic Oscillator Stabilized By A Hyperfine Atomic Transition

NASA Technical Reports Server (NTRS)

Strekalov, Dmitry; Aveline, David; Matsko, Andrey B.; Thompson, Robert; Yu, Nan

2004-01-01

Opto-electronic oscillator (OEO) is a closed-loop system with part of the loop is implemented by an optical beam, and the rest by RF circuitry. The technological advantage of this approach over traditional all-RF loops in the gigahertz range comes from the that frequency filtering can be done far more efficiently in the optical range with compact, low power, and have superior stability. In this work, we report our preliminary results on using the phenomenon of coherent population trapping in (87) Rb vapor as an optical filter. Such a filter allows us to stabilize the OEO at the hyperfine splitting frequency of rubidium, thus implementing a novel type of frequency standard.

Influence of the ac-Stark shift on GPS atomic clock timekeeping

NASA Astrophysics Data System (ADS)

Formichella, V.; Camparo, J.; Tavella, P.

2017-01-01

The ac-Stark shift (or light shift) is a fundamental aspect of the field/atom interaction arising from virtual transitions between atomic states, and as Alfred Kastler noted, it is the real-photon counterpart of the Lamb shift. In the rubidium atomic frequency standards (RAFS) flying on Global Positioning System (GPS) satellites, it plays an important role as one of the major perturbations defining the RAFS' frequency: the rf-discharge lamp in the RAFS creates an atomic signal via optical pumping and simultaneously perturbs the atoms' ground-state hyperfine splitting via the light shift. Though the significance of the light shift has been known for decades, to date there has been no concrete evidence that it limits the performance of the high-quality RAFS flying on GPS satellites. Here, we show that the long-term frequency stability of GPS RAFS is primarily determined by the light shift as a consequence of stochastic jumps in lamplight intensity. Our results suggest three paths forward for improved GPS system timekeeping: (1) reduce the light-shift coefficient of the RAFS by careful control of the lamp's spectrum; (2) operate the lamp under conditions where lamplight jumps are not so pronounced; and (3) employ a light source for optical pumping that does not suffer pronounced light jumps (e.g., a diode laser).

Chip Scale Atomic Resonator Frequency Stabilization System With Ultra-Low Power Consumption for Optoelectronic Oscillators.

PubMed

Zhao, Jianye; Zhang, Yaolin; Lu, Haoyuan; Hou, Dong; Zhang, Shuangyou; Wang, Zhong

2016-07-01

We present a long-term chip scale stabilization scheme for optoelectronic oscillators (OEOs) based on a rubidium coherent population trapping (CPT) atomic resonator. By locking a single mode of an OEO to the (85)Rb 3.035-GHz CPT resonance utilizing an improved phase-locked loop (PLL) with a PID regulator, we achieved a chip scale frequency stabilization system for the OEO. The fractional frequency stability of the stabilized OEO by overlapping Allan deviation reaches 6.2 ×10(-11) (1 s) and  ∼ 1.45 ×10 (-11) (1000 s). This scheme avoids a decrease in the extra phase noise performance induced by the electronic connection between the OEO and the microwave reference in common injection locking schemes. The total physical package of the stabilization system is [Formula: see text] and the total power consumption is 400 mW, which provides a chip scale and portable frequency stabilization approach with ultra-low power consumption for OEOs.

Sub-Doppler two-photon absorption induced by the combination of a single-mode laser and a frequency comb

NASA Astrophysics Data System (ADS)

Moreno, Marco P.; Nogueira, Giovana T.; Felinto, Daniel; Vianna, Sandra S.

2017-08-01

The two-photon transition 5 S -5 P -5 D in rubidium vapor is investigated by detecting the fluorescence from the 6 P3 /2 state when the atomic system is excited by the combined action of a cw diode laser and a frequency comb. The cw laser plays a role as a velocity-selective filter and allows for sub-Doppler spectroscopy over a large spectral range including the 5 D3 /2 and 5 D5 /2 states. For a counterpropagating beam configuration, the response of each atomic velocity group is well characterized within the Doppler profile and the excited hyperfine levels are clearly resolved. The contribution of the optical pumping to the direct two-photon process is also revealed. The results are well described in a frequency domain picture by considering the interaction of each velocity group with the cw laser and the modes of the frequency comb.

Ultrafast laser control of backward superfluorescence towards standoff sensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ariunbold, Gombojav O.; National University of Mongolia, Ulaanbaatar 210646; Baylor University, Waco, Texas 76798

2014-01-13

We study infrared backward cooperative emission in a rubidium vapor induced by ultrafast two-photon optical excitations. The laser coherent control of the backward emission is demonstrated by using a pair of 100 fs pulses with a variable time delay. The temporal variation (quantum beat) of the backward beam intensity due to interference of atomic transitions in the rubidium atomic level system 5S-5P-5D is produced and controlled. Based on the obtained experimental results, we discuss possible applications of the developed approach for creation of an effective “guide star” in the sodium atomic layer in the upper atmosphere (mesosphere)

Atom-Resonant Heralded Single Photons by Interaction-Free Measurement

NASA Astrophysics Data System (ADS)

Wolfgramm, Florian; de Icaza Astiz, Yannick A.; Beduini, Federica A.; Cerè, Alessandro; Mitchell, Morgan W.

2011-02-01

We demonstrate the generation of rubidium-resonant heralded single photons for quantum memories. Photon pairs are created by cavity-enhanced down-conversion and narrowed in bandwidth to 7 MHz with a novel atom-based filter operating by “interaction-free measurement” principles. At least 94% of the heralded photons are atom-resonant as demonstrated by a direct absorption measurement with rubidium vapor. A heralded autocorrelation measurement shows gc(2)(0)=0.040±0.012, i.e., suppression of multiphoton contributions by a factor of 25 relative to a coherent state. The generated heralded photons can readily be used in quantum memories and quantum networks.

On-orbit frequency stability analysis of the GPS NAVSTAR-1 quartz clock and the NAVSTARs-6 and -8 rubidium clocks

NASA Technical Reports Server (NTRS)

Mccaskill, T. B.; Buisson, J. A.; Reid, W. G.

1984-01-01

An on-orbit frequency stability performance analysis of the GPS NAVSTAR-1 quartz clock and the NAVSTARs-6 and -8 rubidium clocks is presented. The clock offsets were obtained from measurements taken at the GPS monitor stations which use high performance cesium standards as a reference. Clock performance is characterized through the use of the Allan variance, which is evaluated for sample times of 15 minutes to two hours, and from one day to 10 days. The quartz and rubidium clocks' offsets were corrected for aging rate before computing the frequency stability. The effect of small errors in aging rate is presented for the NAVSTAR-8 rubidium clock's stability analysis. The analysis includes presentation of time and frequency residuals with respect to linear and quadratic models, which aid in obtaining aging rate values and identifying systematic and random effects. The frequency stability values were further processed with a time domain noise process analysis, which is used to classify random noise process and modulation type.

Fischer–Tropsch Synthesis: Characterization Rb Promoted Iron Catalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarkar,A.; Jacobs, G.; Ji, Y.

Rubidium promoted iron Fischer-Tropsch synthesis (FTS) catalysts were prepared with two Rb/Fe atomic ratios (1.44/100 and 5/100) using rubidium nitrate and rubidium carbonate as rubidium precursors. Results of catalytic activity and deactivation studies in a CSTR revealed that rubidium promoted catalysts result in a steady conversion with a lower deactivation rate than that of the corresponding unpromoted catalyst although the initial activity of the promoted catalyst was almost half that of the unpromoted catalyst. Rubidium promotion results in lower methane production, and higher CO2, alkene and 1-alkene fraction in FTS products. M{umlt o}ssbauer spectroscopic measurements of CO activated and workingmore » catalyst samples indicated that the composition of the iron carbide phase formed after carbidization was -Fe5 C2 for both promoted and unpromoted catalysts. However, in the case of the rubidium promoted catalyst, '-Fe2.2C became the predominant carbidic phase as FTS continued and the overall catalyst composition remained carbidic in nature. In contrast, the carbide content of the unpromoted catalyst was found to decline very quickly as a function of synthesis time. Results of XANES and EXAFS measurements suggested that rubidium was present in the oxidized state and that the compound most prevalent in the active catalyst samples closely resembled that of rubidium carbonate.« less

Nonlinear Spectroscopy of Rubidium: An Undergraduate Experiment

ERIC Educational Resources Information Center

Jacques, V.; Hingant, B.; Allafort, A.; Pigeard, M.; Roch, J. F.

2009-01-01

In this paper, we describe two complementary nonlinear spectroscopy methods which both allow one to achieve Doppler-free spectra of atomic gases. First, saturated absorption spectroscopy is used to investigate the structure of the 5S[subscript 1/2] [right arrow] 5P[subscript 3/2] transition in rubidium. Using a slightly modified experimental…

Experimental generation of tripartite polarization entangled states of bright optical beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Liang; Liu, Yanhong; Deng, Ruijie

The multipartite polarization entangled states of bright optical beams directly associating with the spin states of atomic ensembles are one of the essential resources in the future quantum information networks, which can be conveniently utilized to transfer and convert quantum states across a network composed of many atomic nodes. In this letter, we present the experimental demonstration of tripartite polarization entanglement described by Stokes operators of optical field. The tripartite entangled states of light at the frequency resonant with D1 line of Rubidium atoms are transformed into the continuous variable polarization entanglement among three bright optical beams via an opticalmore » beam splitter network. The obtained entanglement is confirmed by the extended criterion for polarization entanglement of multipartite quantized optical modes.« less

Compact mode-locked diode laser system for high precision frequency comparisons in microgravity

NASA Astrophysics Data System (ADS)

Christopher, H.; Kovalchuk, E. V.; Wicht, A.; Erbert, G.; Tränkle, G.; Peters, A.

2017-11-01

Nowadays cold atom-based quantum sensors such as atom interferometers start leaving optical labs to put e.g. fundamental physics under test in space. One of such intriguing applications is the test of the Weak Equivalence Principle, the Universality of Free Fall (UFF), using different quantum objects such as rubidium (Rb) and potassium (K) ultra-cold quantum gases. The corresponding atom interferometers are implemented with light pulses from narrow linewidth lasers emitting near 767 nm (K) and 780 nm (Rb). To determine any relative acceleration of the K and Rb quantum ensembles during free fall, the frequency difference between the K and Rb lasers has to be measured very accurately by means of an optical frequency comb. Micro-gravity applications not only require good electro-optical characteristics but are also stringent in their demand for compactness, robustness and efficiency. For frequency comparison experiments the rather complex fiber laser-based frequency comb system may be replaced by one semiconductor laser chip and some passive components. Here we present an important step towards this direction, i.e. we report on the development of a compact mode-locked diode laser system designed to generate a highly stable frequency comb in the wavelength range of 780 nm.

Studies on Temperature Dependence of Rubidium Lamp for Atomic Frequency Standard

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghosal, Bikash; Banik, Alak; Vats, Vaibhav

2011-10-20

Rb lamp is a very critical component of the Rb atomic clock's Physics Package. The Rb lamp's performance is very sensitive to temperature and its stability. In this paper we discuss the behaviors of Rb Lamp with temperature. The Rb lamp exciter power and temperature of Rb bulb are very important parameters in controlling the performance of the Rb Lamp. It is observed that at temperatures beyond 110 deg. C, the lamp mode changes from the ring to red mode resulting in abnormal broadening of emission lines and self reversal. The results of our studies on spectral analysis of Rbmore » lamp under various operating conditions are reported in the paper.« less

GPS Block 2R Time Standard Assembly (TSA) architecture

NASA Technical Reports Server (NTRS)

Baker, Anthony P.

1990-01-01

The underlying philosophy of the Global Positioning System (GPS) 2R Time Standard Assembly (TSA) architecture is to utilize two frequency sources, one fixed frequency reference source and one system frequency source, and to couple the system frequency source to the reference frequency source via a sample data loop. The system source is used to provide the basic clock frequency and timing for the space vehicle (SV) and it uses a voltage controlled crystal oscillator (VCXO) with high short term stability. The reference source is an atomic frequency standard (AFS) with high long term stability. The architecture can support any type of frequency standard. In the system design rubidium, cesium, and H2 masers outputting a canonical frequency were accommodated. The architecture is software intensive. All VCXO adjustments are digital and are calculated by a processor. They are applied to the VCXO via a digital to analog converter.

Frequency stability of maser oscillators operated with cavity Q. [hydrogen and rubidium masers

NASA Technical Reports Server (NTRS)

Tetu, M.; Tremblay, P.; Lesage, P.; Petit, P.; Audoin, C.

1982-01-01

The short term frequency stability of masers equipped with an external feedback loop to increase the cavity quality factor was studied. The frequency stability of a hydrogen and a rubidium maser were measured and compared with theoretical evaluation. It is shown that the frequency stability passes through an optimum when the cavity Q is varied. Long term fluctuations are discussed and the optimum mid term frequency stability achievably by small size active and passive H-masers is considered.

Coherent blue emission generated by Rb two-photon excitation using diode and femtosecond lasers

NASA Astrophysics Data System (ADS)

Lopez, Jesus P.; Moreno, Marco P.; de Miranda, Marcio H. G.; Vianna, Sandra S.

2017-04-01

The coherent blue light generated in rubidium vapor due to the combined action of an ultrashort pulse train and a continuous wave diode laser is investigated. Each step of the two-photon transition 5S-5P{}3/2-5D is excited by one of the lasers, and the induced coherence between the 5S and 6P{}3/2 states is responsible for generating the blue beam. Measurements of the excitation spectrum reveal the frequency comb structure and allow us to identify the resonant modes responsible for inducing the nonlinear process. Further, each resonant mode excites a different group of atoms, making the process selective in atomic velocity. The signal dependency on the atomic density is characterized by a sharp growth and a rapid saturation. We also show that for high intensity of the diode laser, the Stark shift at resonance causes the signal suppression observed at low atomic density.

Optical Amplification of Spin Noise Spectroscopy via Homodyne Detection

NASA Astrophysics Data System (ADS)

Sterin, Pavel; Wiegand, Julia; Hübner, Jens; Oestreich, Michael

2018-03-01

Spin noise (SN) spectroscopy measurements on delicate semiconductor spin systems, like single (In,Ga)As quantum dots, are currently not limited by optical shot noise but rather by the electronic noise of the detection system. We report on a realization of homodyne SN spectroscopy enabling shot-noise-limited SN measurements. The proof-of-principle measurements on impurities in an isotopically enriched rubidium atom vapor show that homodyne SN spectroscopy can be utilized even in the low-frequency spectrum, which facilitates advanced semiconductor spin research like higher order SN measurements on spin qubits.

A stabilized optical frequency comb based on an Er-doped fiber femtosecond laser

NASA Astrophysics Data System (ADS)

Xia, Chuanqing; Wu, Tengfei; Zhao, Chunbo; Xing, Shuai

2018-03-01

An optical frequency comb based on a 250 MHz home-made Er-doped fiber femtosecond laser is presented in this paper. The Er-doped fiber laser has a ring cavity and operates mode-locked in femtosecond regime with the technique of nonlinear polarization rotation. The pulse duration is 118 fs and the spectral width is 30 nm. A part of the femtosecond laser is amplified in Er-doped fiber amplifier before propagating through a piece of highly nonlinear fiber for expanding the spectrum. The carrier-envelope offset frequency of the comb which has a signal-to-noise ratio more than 35 dB is extracted by means of f-2f beating. It demonstrates that both carrier-envelope offset frequency and repetition frequency keep phase locked to a Rubidium atomic clock simultaneously for 2 hours. The frequency stabilized fiber combs will be increasingly applied in optical metrology, attosecond pulse generation, and absolute distance measurement.

Introduction to Quartz Frequency Standards

DTIC Science & Technology

1992-03-01

changes is 5 X 10-"N. Gas permeation under conditions where there is an abnormally high concentration of hydrogen or helium in the atmosphere can lead...Rubidium Life Rubidium depletion Power Buffer gas depletion __________Weight Glass contaminants Cesium Life Cesium supply depletion Power Spent cesium... Tifton , R., Electronic Activity Dip Measurement, IEEE Trans. on Instrumentation and Measurement, Vol. IM-27, pp. 59-65, 1978. 23. Ballato, A., Frequency

Dressed Gain from the Parametrically Amplified Four-Wave Mixing Process in an Atomic Vapor.

PubMed

Zhang, Zhaoyang; Wen, Feng; Che, Junling; Zhang, Dan; Li, Changbiao; Zhang, Yanpeng; Xiao, Min

2015-10-14

With a forward cone emitting from the strong pump laser in a thermal rubidium atomic vapor, we investigate the non-degenerate parametrically amplified four-wave mixing (PA-FWM) process with dressing effects in a three-level "double-Λ" configuration both theoretically and experimentally. By seeding a weak probe field into the Stokes or anti-Stokes channel of the FWM, the gain processes are generated in the bright twin beams which are called conjugate and probe beams, respectively. However, the strong dressing effect of the pump beam will dramatically affect the gain factors both in the probe and conjugate channels, and can inevitably impose an influence on the quantum effects such as entangled degree and the quantum noise reduction between the two channels. We systematically investigate the intensity evolution of the dressed gain processes by manipulating the atomic density, the Rabi frequency and the frequency detuning. Such dressing effects are also visually evidenced by the observation of Autler-Townes splitting of the gain peaks. The investigation can contribute to the development of quantum information processing and quantum communications.

Dressed Gain from the Parametrically Amplified Four-Wave Mixing Process in an Atomic Vapor

NASA Astrophysics Data System (ADS)

Zhang, Zhaoyang; Wen, Feng; Che, Junling; Zhang, Dan; Li, Changbiao; Zhang, Yanpeng; Xiao, Min

2015-10-01

With a forward cone emitting from the strong pump laser in a thermal rubidium atomic vapor, we investigate the non-degenerate parametrically amplified four-wave mixing (PA-FWM) process with dressing effects in a three-level “double-Λ” configuration both theoretically and experimentally. By seeding a weak probe field into the Stokes or anti-Stokes channel of the FWM, the gain processes are generated in the bright twin beams which are called conjugate and probe beams, respectively. However, the strong dressing effect of the pump beam will dramatically affect the gain factors both in the probe and conjugate channels, and can inevitably impose an influence on the quantum effects such as entangled degree and the quantum noise reduction between the two channels. We systematically investigate the intensity evolution of the dressed gain processes by manipulating the atomic density, the Rabi frequency and the frequency detuning. Such dressing effects are also visually evidenced by the observation of Autler-Townes splitting of the gain peaks. The investigation can contribute to the development of quantum information processing and quantum communications.

Intensity noise properties of a compact laser device based on a miniaturized MOPA system for spectroscopic applications

NASA Astrophysics Data System (ADS)

Baumgärtner, S.; Juhl, S.; Opalevs, D.; Sahm, A.; Hofmann, J.; Leisching, P.; Paschke, K.

2018-02-01

We present a novel compact laser device based on a semiconductor master-oscillator power-amplifier (MOPA) emitting at 772 nm, suitable for quantum optic and spectroscopy. The optical performance of the laser device is characterized. For miniaturized lasers the thermal management is challenging, we therefore perform thermal simulations and measurements. The first demonstrator is emitting more than 3 W optical power with a linewidth below 2lMHz. Using this MOPA design also compact devices for quantum optics (e.g. rubidium atomic clock) and seed lasers for frequency conversion can be realized [1].

Electrodeless-discharge-vapor-lamp-based Faraday anomalous-dispersion optical filter.

PubMed

Sun, Qinqing; Zhuang, Wei; Liu, Zhiwen; Chen, Jingbiao

2011-12-01

We report an excited-state Faraday anomalous-dispersion optical filter operating on the rubidium 5P(3/2)-5D(5/2) transition (775.9 nm in vacuum) without the use of a pump laser. An electrodeless discharge vapor lamp is employed to replace the Rb vapor cell in a traditional Faraday anomalous-dispersion optical filter system. Atoms can be excited by power rather than a complex frequency-locked pump laser. A proof-of-concept experimental demonstration with a maximum transmission of 1.9% and a filter bandwidth of 650 MHz is presented. © 2011 Optical Society of America

Multi-mode of Four and Six Wave Parametric Amplified Process

NASA Astrophysics Data System (ADS)

Zhu, Dayu; Yang, Yiheng; Zhang, Da; Liu, Ruizhou; Ma, Danmeng; Li, Changbiao; Zhang, Yanpeng

2017-03-01

Multiple quantum modes in correlated fields are essential for future quantum information processing and quantum computing. Here we report the generation of multi-mode phenomenon through parametric amplified four- and six-wave mixing processes in a rubidium atomic ensemble. The multi-mode properties in both frequency and spatial domains are studied. On one hand, the multi-mode behavior is dominantly controlled by the intensity of external dressing effect, or nonlinear phase shift through internal dressing effect, in frequency domain; on the other hand, the multi-mode behavior is visually demonstrated from the images of the biphoton fields directly, in spatial domain. Besides, the correlation of the two output fields is also demonstrated in both domains. Our approach supports efficient applications for scalable quantum correlated imaging.

Multi-mode of Four and Six Wave Parametric Amplified Process.

PubMed

Zhu, Dayu; Yang, Yiheng; Zhang, Da; Liu, Ruizhou; Ma, Danmeng; Li, Changbiao; Zhang, Yanpeng

2017-03-03

Multiple quantum modes in correlated fields are essential for future quantum information processing and quantum computing. Here we report the generation of multi-mode phenomenon through parametric amplified four- and six-wave mixing processes in a rubidium atomic ensemble. The multi-mode properties in both frequency and spatial domains are studied. On one hand, the multi-mode behavior is dominantly controlled by the intensity of external dressing effect, or nonlinear phase shift through internal dressing effect, in frequency domain; on the other hand, the multi-mode behavior is visually demonstrated from the images of the biphoton fields directly, in spatial domain. Besides, the correlation of the two output fields is also demonstrated in both domains. Our approach supports efficient applications for scalable quantum correlated imaging.

Radio-frequency-modulated Rydberg states in a vapor cell

NASA Astrophysics Data System (ADS)

Miller, S. A.; Anderson, D. A.; Raithel, G.

2016-05-01

We measure strong radio-frequency (RF) electric fields using rubidium Rydberg atoms prepared in a room-temperature vapor cell as field sensors. Electromagnetically induced transparency is employed as an optical readout. We RF-modulate the 60{{{S}}}1/2 and 58{{{D}}}5/2 Rydberg states with 50 and 100 MHz fields, respectively. For weak to moderate RF fields, the Rydberg levels become Stark-shifted, and sidebands appear at even multiples of the driving frequency. In high fields, the adjacent hydrogenic manifold begins to intersect the shifted levels, providing rich spectroscopic structure suitable for precision field measurements. A quantitative description of strong-field level modulation and mixing of S and D states with hydrogenic states is provided by Floquet theory. Additionally, we estimate the shielding of DC electric fields in the interior of the glass vapor cell.

Gas-cell atomic clocks for space: new results and alternative schemes

NASA Astrophysics Data System (ADS)

Affolderbach, C.; Breschi, E.; Schori, C.; Mileti, G.

2017-11-01

We present our development activities on compact Rubidium gas-cell atomic frequency standards, for use in space-borne and ground-based applications. We experimentally demonstrate a high-performance laser optically-pumped Rb clock for space applications such as telecommunications, science missions, and satellite navigation systems (e.g. GALILEO). Using a stabilised laser source and optimized gas cells, we reach clock stabilities as low as 1.5·10-12 τ-1/2 up to 103 s and 4·10-14 at 104 s. The results demonstrate the feasibility of a laser-pumped Rb clock reaching < 1·10-12 τ-1/2 in a compact device (<2 liters, 2 kg, 20 W), given optimization of the implemented techniques. A second activity concerns more radically miniaturized gas-cell clocks, aiming for low power consumption and a total volume around 1 cm3 , at the expense of relaxed frequency stability. Here miniaturized "chip-scale" vapour cells and use of coherent laser interrogation techniques are at the heart of the investigations.

Forming Rb(+) snowballs in the center of He nanodroplets.

PubMed

Theisen, Moritz; Lackner, Florian; Ernst, Wolfgang E

2010-12-07

Helium nanodroplets doped with rubidium atoms are ionized by applying a resonant two-step ionization scheme. Subsequent immersion of rubidium ions is observed in time-of-flight mass spectra. While alkali-metal atoms usually desorb from the surface of a helium nanodroplet upon electronic excitation, rubidium in its excited 5(2)P(1/2) state provides an exception from this rule (Auböck et al., Phys. Rev. Lett., 2008, 101, 35301). In our new experiment, Rb atoms are selectively excited either to the 5(2)P(1/2) or to the 5(2)P(3/2) state. From there they are ionized by a laser pulse. Time-of-flight mass spectra of the ionization products reveal that the intermediate population of the 5(2)P(1/2) state does not only make the ionization process Rb-monomer selective, but also gives rise to a very high yield of Rb(+)-He(N) complexes. Ions with masses of up to several thousand amu have been monitored, which can be explained by an immersion of the single Rb ion into the He nanodroplet, where most likely a snowball is formed in the center of the He nanodroplet. As the most stable position for an ion is in the center of a He nanodroplet, our results agree well with theory.

Using optical masks to create and image sub-optical wavelength atomic structures in a MOT

NASA Astrophysics Data System (ADS)

Turlapov, Andrey; Tonyushkin, Aleksey; Sleator, Tycho

2002-05-01

We have used an ``optical mask'' for Rubidium atoms in a magneto-optical trap to create and image atomic density gratings with periodicities as small as 1/8th of an optical wavelength ( ˜ 100 nm). The mask consists of a pulse of an optical standing wave (wavelength λ) resonant to an open atomic transition. The interaction pumps all atoms except those near the nodes into another hyperfine ground state, leaving a grating of ``spikes'' in atomic density in the initial ground state. The nodes of the standing wave serve as slits of the mask. By applying two such masks separated by time T, we have created atomic gratings of period λ/(2n) (or smaller) at times (n+1)/n T after the first mask pulse. For T on the order of the Talbot time (or inverse recoil frequency), quantum effects are important for the dynamics of the atomic center of mass. Under appropriate conditions, these quantum effects led to a reduction of the period of the resulting density gratings (Talbot-Lau effect). The resulting density gratings of period λ/2n (for n=1 to 4) were imaged in real time using an additional optical mask.

The blue light indicator in rubidium 5S-5P-5D cascade excitation

NASA Astrophysics Data System (ADS)

Raja, Waseem; Ali, Md. Sabir; Chakrabarti, Alok; Ray, Ayan

2017-07-01

The cascade system has played an important role in contemporary research areas related to fields like Rydberg excitation, four wave mixing and non-classical light generation, etc. Depending on the specific objective, co or counter propagating pump-probe laser experimental geometry is followed. However, the stepwise excitation of atoms to states higher than the first excited state deals with increasingly much fewer number of atoms even compared to the population at first excited level. Hence, one needs a practical indicator to study the complex photon-atom interaction of the cascade system. Here, we experimentally analyze the case of rubidium 5S → 5P → 5D as a specimen of two-step excitation and highlight the efficacy of monitoring one branch, which emits 420 nm, of associated cascade decay route 5D → 6P → 5S, as an effective monitor of the coherence in the system.

Frequency measurement of the 5 S{1}/{2}(F = 3)-5 D{5}/{2}(F = 5) two-photon transition in rubidium

NASA Astrophysics Data System (ADS)

Touahri, D.; Acef, O.; Clairon, A.; Zondy, J.-J.; Felder, R.; Hilico, L.; de Beauvoir, B.; Biraben, F.; Nez, F.

1997-02-01

We have measured the frequencies of three diode lasers stabilized on the 5 S{1}/{2}(F = 3)-5 D{5}/{2}(F = 5) two-photon transition in rubidium at λ = 778.1 nm, with an uncertainty of 1 kHz, using BNM-LPTF frequency synthesis chain starting from a {CO 2}/{OsO 4} reference laser at 10.3 μm. We show that this frequency chain is able to reach the 10 -13 resolution level. After a discussion of the systematic effects that may shift the resonance, the transition frequency is found to be ν = 385 285 142 378.280 ± 2 kHz.

Scattering of positrons and electrons by alkali atoms

NASA Technical Reports Server (NTRS)

Stein, T. S.; Kauppila, W. E.; Kwan, C. K.; Lukaszew, R. A.; Parikh, S. P.; Wan, Y. J.; Zhou, S.; Dababneh, M. S.

1990-01-01

Absolute total scattering cross sections (Q sub T's) were measured for positrons and electrons colliding with sodium, potassium, and rubidium in the 1 to 102 eV range, using the same apparatus and experimental approach (a beam transmission technique) for both projectiles. The present results for positron-sodium and -rubidium collisions represent the first Q sub T measurements reported for these collision systems. Features which distinguish the present comparisons between positron- and electron-alkali atom Q sub T's from those for other atoms and molecules (room-temperature gases) which have been used as targets for positrons and electrons are the proximity of the corresponding positron- and electron-alkali atom Q sub T's over the entire energy range of overlap, with an indication of a merging or near-merging of the corresponding positron and electron Q sub T's near (and above) the relatively low energy of about 40 eV, and a general tendency for the positron-alkali atom Q sub T's to be higher than the corresponding electron values as the projectile energy is decreased below about 40 eV.

Generation of subnatural-linewdith biphotons from a hot rubidium atomic vapor cell

NASA Astrophysics Data System (ADS)

Zhu, Lingbang; Shu, Chi; Guo, Xianxin; Chen, Peng; Xiao, Yanhong; Jeong, Heejeong; Du, Shengwang

2017-04-01

We report the generation of narrowband entangled photon pairs (biphotons) from a hot atomic vapor cell. Making use of backward spontaneous four-wave mixing with electromagnetically induced transparency (EIT), we produced subnatural-linewidth (1.9 MHz < 6 MHz) biphotons from a Doppler-broadened (0.5 GHz) hot (63 C) paraffin-coated rubidium 87 vapor cell. The biphoton coherence time is controable and can be tuned up to 100 ns by EIT. The uncorrelated photons from resonance Raman scattering are suppressed by a spatially separated and tailored optical pumping beam. The spectral brightness is as high as 14,000 s- 1 MHz- 1 . As compared with the cold-atom experiment , the hot atomic vapour cell configuration is much simpler for operation and maintenance, and it is a continuous biphoton source. Our demonstration may lead to miniature narrowband biphoton sources based on atomic vapour cells for practical quantum applications and engineering. The work was supported by Hong Kong Research Grants Council (Project No. 16301214), and in part by the CAS/SAFEA International Partnership Program for Creative Research Teams. L.Z. acknowledges support from the Undergraduate Research Opportunities Program.

Optimal and robust control of quantum state transfer by shaping the spectral phase of ultrafast laser pulses.

PubMed

Guo, Yu; Dong, Daoyi; Shu, Chuan-Cun

2018-04-04

Achieving fast and efficient quantum state transfer is a fundamental task in physics, chemistry and quantum information science. However, the successful implementation of the perfect quantum state transfer also requires robustness under practically inevitable perturbative defects. Here, we demonstrate how an optimal and robust quantum state transfer can be achieved by shaping the spectral phase of an ultrafast laser pulse in the framework of frequency domain quantum optimal control theory. Our numerical simulations of the single dibenzoterrylene molecule as well as in atomic rubidium show that optimal and robust quantum state transfer via spectral phase modulated laser pulses can be achieved by incorporating a filtering function of the frequency into the optimization algorithm, which in turn has potential applications for ultrafast robust control of photochemical reactions.

Spectral emission from the alkali inductively-coupled plasma: Theory and experiment

NASA Astrophysics Data System (ADS)

Bazurto, R.; Huang, M.; Camparo, J.

2018-04-01

The weakly-ionized, alkali inductively-coupled plasma (ICP) has a long history as the light source for optical pumping. Today, its most significant application is perhaps in the rubidium atomic frequency standard (RAFS), arguably the workhorse of atomic timekeeping in space, where it is crucial to the RAFS' functioning and performance (and routinely referred to as the RAFS' "rf-discharge lamp"). In particular, the photon flux from the lamp determines the signal-to-noise ratio of the device, and variations in ICP brightness define the long-term frequency stability of the atomic clock as a consequence of the ac-Stark shift (i.e., the light-shift). Given the importance of Rb atomic clocks to diverse satellite navigation systems (e.g., GPS, Galileo, BeiDou) - and thereby the importance of alkali ICPs to these systems - it is somewhat surprising to find that the physical processes occurring within the discharge are not well understood. As a consequence, researchers do not understand how to improve the spectral emission from the lamp except at a trial-and-error level, nor do they fully understand the nonlinear mechanisms that result in ICP light instability. Here, we take a first step in developing an intuitive, semi-quantitative model of the alkali rf-discharge lamp, and we perform a series of experiments to validate the theory's predictions.

The Rubidium Atomic Clock and Basic Research

DTIC Science & Technology

2007-12-10

from orbiting GPS (global positioning system) satellites. Thankfully, you make it home without an exciting but har- rowing story to tell family...the vapor-cell atomic clock, -i\\till is elec- tronically tied to an atomic resonance, thereby transferring the stability of atomic structure to the...are applied to the resonance cell, there is a net transfer of atoms from F = 1 back into F = 2 and a decrease in transmitted light intensity. The

Pump-probe study of the formation of rubidium molecules by ultrafast photoassociation of ultracold atoms

NASA Astrophysics Data System (ADS)

McCabe, David J.; England, Duncan G.; Martay, Hugo E. L.; Friedman, Melissa E.; Petrovic, Jovana; Dimova, Emiliya; Chatel, Béatrice; Walmsley, Ian A.

2009-09-01

An experimental pump-probe study of the photoassociative creation of translationally ultracold rubidium molecules is presented together with numerical simulations of the process. The formation of loosely bound excited-state dimers is observed as a first step toward a fully coherent pump-dump approach to the stabilization of Rb2 into its lowest ground vibrational states. The population that contributes to the pump-probe process is characterized and found to be distinct from a background population of preassociated molecules.

Extended Coherence Time on the Clock Transition of Optically Trapped Rubidium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kleine Buening, G.; Will, J.; Ertmer, W.

2011-06-17

Optically trapped ensembles are of crucial importance for frequency measurements and quantum memories but generally suffer from strong dephasing due to inhomogeneous density and light shifts. We demonstrate a drastic increase of the coherence time to 21 s on the magnetic field insensitive clock transition of {sup 87}Rb by applying the recently discovered spin self-rephasing [C. Deutsch et al., Phys. Rev. Lett. 105, 020401 (2010)]. This result confirms the general nature of this new mechanism and thus shows its applicability in atom clocks and quantum memories. A systematic investigation of all relevant frequency shifts and noise contributions yields a stabilitymore » of 2.4x10{sup -11{tau}-1/2}, where {tau} is the integration time in seconds. Based on a set of technical improvements, the presented frequency standard is predicted to rival the stability of microwave fountain clocks in a potentially much more compact setup.« less

Observation of the 5 p3 /2→6 p3 /2 electric-dipole-forbidden transition in atomic rubidium using optical-optical double-resonance spectroscopy

NASA Astrophysics Data System (ADS)

Ponciano-Ojeda, F.; Hernández-Gómez, S.; López-Hernández, O.; Mojica-Casique, C.; Colín-Rodríguez, R.; Ramírez-Martínez, F.; Flores-Mijangos, J.; Sahagún, D.; Jáuregui, R.; Jiménez-Mier, J.

2015-10-01

Direct evidence of excitation of the 5 p3 /2→6 p3 /2 electric-dipole-forbidden transition in atomic rubidium is presented. The experiments were performed in a room-temperature rubidium cell with continuous-wave external cavity diode lasers. Optical-optical double-resonance spectroscopy with counterpropagating beams allows the detection of the nondipole transition free of Doppler broadening. The 5 p3 /2 state is prepared by excitation with a laser locked to the maximum F cyclic transition of the D2 line, and the forbidden transition is produced by excitation with a 911 nm laser. Production of the forbidden transition is monitored by detection of the 420 nm fluorescence that results from decay of the 6 p3 /2 state. Spectra with three narrow lines (≈13 MHz FWHM) with the characteristic F -1 , F , and F +1 splitting of the 6 p3 /2 hyperfine structure in both rubidium isotopes were obtained. The results are in very good agreement with a direct calculation that takes into account the 5 s →5 p3 /2 preparation dynamics, the 5 p3 /2→6 p3 /2 nondipole excitation geometry, and the 6 p3 /2→5 s1 /2 decay. The comparison also shows that the electric-dipole-forbidden transition is a very sensitive probe of the preparation dynamics.

Ultrabright, narrow-band photon-pair source for atomic quantum memories

NASA Astrophysics Data System (ADS)

Tsai, Pin-Ju; Chen, Ying-Cheng

2018-06-01

We demonstrate an ultrabright, narrow-band and frequency-tunable photon-pair source based on cavity-enhanced spontaneous parametric down conversion (SPDC) which is compatible with atomic transition of rubidium D 2-line (780 nm) or cesium D 2-line (852 nm). With the pump beam alternating between a high and a low power phase, the output is switching between the optical parametric oscillator (OPO) and photon-pair generation mode. We utilize the OPO output light to lock the cavity length to maintain the double resonances of signal and idler, as well as to lock the signal frequency to cesium atomic transition. With a type-II phase matching and a double-passed pump scheme such that the cluster frequency spacing is larger than the SPDC bandwidth, the photon-pair output is in a nearly single-mode operation as confirmed by a scanning Fabry–Perot interferometer with its output detected by a photomultiplier. The achieved generation and detection rates are 7.24× {10}5 and 6142 s‑1 mW‑1, respectively. The correlation time of the photon pair is 21.6(2.2) ns, corresponding to a bandwidth of 2π × 6.6(6) MHz. The spectral brightness is 1.06× {10}5 s‑1 mW‑1 MHz‑1. This is a relatively high value under a single-mode operation with the cavity-SPDC scheme. The generated single photons can be readily used in experiments related to atomic quantum memories.

Dynamics of solvation and desolvation of rubidium attached to He nanodroplets

NASA Astrophysics Data System (ADS)

von Vangerow, J.; John, O.; Stienkemeier, F.; Mudrich, M.

2015-07-01

The real-time dynamics of photoexcited and photoionized rubidium (Rb) atoms attached to helium (He) nanodroplets is studied by femtosecond pump-probe mass spectrometry. While excited Rb atoms in the perturbed 6p-state (Rb*) desorb off the He droplets, Rb+ photoions tend to sink into the droplet interior when created near the droplet surface. The transition from Rb+ solvation to full Rb* desorption is found to occur at a delay time τ ˜ 600 fs for Rb* in the 6pΣ-state and τ ˜ 1200 fs for the 6pΠ-state. Rb+He ions are found to be created by directly exciting bound Rb*He exciplex states as well as by populating bound Rb+He-states in a photoassociative ionization process.

Dielectric dispersion in pure and doped lithium rubidium sulphate

NASA Astrophysics Data System (ADS)

Kassem, M. E.; El-Muraikhi, M.; Al-Houty, L.; Mohamed, A. A.

The frequency (102 - 105 Hz) dependence of the dielectric properties of lithium rubidium sulphate (LRS) are reported in the vicinity of the transition temperature Tc = 477 K. The a.c. conductivity σ(ω) shows a strong temperature dependence and weak frequency response. The dielectric constant in this region shows a strong frequency dispersion. A Cole-Cole diagram was used to determine the distribution parameter and the molecular relaxation time. The effect of doping with Dy+3, Sm+3 and V+3, was also studied. It was found that doping gives rise to localized states which produce a disorder in the structure of LiRbSO4.

Recent results of the pulsed optically pumped rubidium clock

NASA Astrophysics Data System (ADS)

Levi, F.; Micalizio, S.; Godone, A.; Calosso, C.; Bertacco, E.

2017-11-01

A laboratory prototype of a pulsed optically pumped (POP) clock based on a rubidium cell with buffer gas is described. This clock has shown very interesting physical and metrological features, such as negligible light-shift, strongly reduced cavity-pulling and very good frequency stability. In this regard, an Allan deviation of σy(τ) = 1.2 τ-1/2 for measurement times up to τ = 105 s has been measured. These results confirm the interesting perspectives of such a frequency standard and make it very attractive for several technological applications, such as radionavigation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biedermann, G. W.; McGuinness, H. J.; Rakholia, A. V.

Here, we demonstrate matter-wave interference in a warm vapor of rubidium atoms. Established approaches to light-pulse atom interferometry rely on laser cooling to concentrate a large ensemble of atoms into a velocity class resonant with the atom optical light pulse. In our experiment, we show that clear interference signals may be obtained without laser cooling. This effect relies on the Doppler selectivity of the atom interferometer resonance. Lastly, this interferometer may be configured to measure accelerations, and we demonstrate that multiple interferometers may be operated simultaneously by addressing multiple velocity classes.

Doppler-free satellites of resonances of electromagnetically induced transparency and absorption on the D 2 lines of alkali metals

NASA Astrophysics Data System (ADS)

Sargsyan, A.; Sarkisyan, D.; Staedter, D.; Akulshin, A. M.

2006-11-01

The peculiarities of intra-Doppler structures that are observed in the atomic absorption spectrum of alkali metals with the help of two independent lasers have been studied. These structures accompany ultranarrow coherent resonances of electromagnetically induced transparency and absorption. With the D 2 line of rubidium taken as an example, it is shown that, in the scheme of unidirectional waves, the maximum number of satellite resonances caused by optical pumping selective with respect to the atomic velocity is equal to seven, while only six resonances are observed in the traditional scheme of saturated absorption with counterpropagating waves of the same frequency. The spectral position of the resonances and their polarity depend on the frequency of the saturating radiation, while their number and relative amplitude depend also on the experimental geometry. These features are of general character and should show themselves in the absorption spectrum on the D 2 lines of all alkali metals. An explanation of these features is given. The calculated spectral separations between the resonances are compared to the experimental ones, and their possible application is discussed.

Collisional Broadening and Shift of D1 and D2 Spectral Lines in Atomic Alkali Vapor - Noble Gas Systems

DTIC Science & Technology

2013-03-01

12 curve fit to the 2Σ1 2� − 2Σ1 2� difference potential Table 2.2a: Lennard - Jones parameters for Rubidium + Helium lines. Difference...Table Page Table 2.2a. Lennard - Jones parameters for Rubidium + Helium lines 22 Table 2.2b. Line broadening and shift parameters for Rb + He lines...all nine M + Ng pairs, using Lennard - Jones (6-12) potentials in Anderson- Talman 25 Table 2.2e. Broadening and shift coefficients (in MHz/torr

Ultracold atoms and their applications (Scientific session of the Physical Sciences Division of the Russian Academy of Sciences, 28 October 2015)

NASA Astrophysics Data System (ADS)

2016-02-01

A scientific session of the Physical Sciences Division of the Russian Academy of Sciences (RAS), "Ultracold atoms and their applications", was held in the conference hall of the Lebedev Physical Institute, RAS, on 28 October 2015.The papers collected in this issue were written based on talks given at the session:(1) Vishnyakova G A, Golovizin A A, Kalganova E S, Tregubov D O, Khabarova K Yu (Lebedev Physical Institute, Russian Academy of Sciences, Moscow; Moscow Institute of Physics and Technology (State University), Dolgoprudnyi, Moscow region), Sorokin V N, Sukachev D D, Kolachevsky N N (Lebedev Physical Institute, Russian Academy of Sciences, Moscow) "Ultracold lanthanides: from optical clock to a quantum simulator"; (2) Barmashova T V, Martiyanov K A, Makhalov V B (Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod), Turlapov A V (Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod; Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod) "Fermi liquid to Bose condensate crossover in a two-dimensional ultracold gas experiment"; (3) Taichenachev A V, Yudin V I, Bagayev S N (Institute of Laser Physics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk; Novosibirsk State University, Novosibirsk) "Ultraprecise optical frequency standards based on ultracold atoms: state of the art and prospects"; (4) Ryabtsev I I, Beterov I I, Tretyakov D B, Entin V M, Yakshina E A (Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk; Novosibirsk State University, Novosibirsk) "Spectroscopy of cold rubidium Rydberg atoms for applications in quantum information". • Ultracold lanthanides: from optical clock to a quantum simulator, G A Vishnyakova, A A Golovizin, E S Kalganova, V N Sorokin, D D Sukachev, D O Tregubov, K Yu Khabarova, N N Kolachevsky Physics-Uspekhi, 2016, Volume 59, Number 2, Pages 168-173 • Fermi liquid-to-Bose condensate crossover in a two-dimensional ultracold gas experiment, T V Barmashova, K A Mart'yanov, V B Makhalov, A V Turlapov Physics-Uspekhi, 2016, Volume 59, Number 2, Pages 174-183 • Ultraprecise optical frequency standards based on ultracold atoms: state of the art and prospects, A V Taichenachev, V I Yudin, S N Bagayev Physics-Uspekhi, 2016, Volume 59, Number 2, Pages 184-195 • Spectroscopy of cold rubidium Rydberg atoms for applications in quantum information, I I Ryabtsev, I I Beterov, D B Tret'yakov, V M Èntin, E A Yakshina Physics-Uspekhi, 2016, Volume 59, Number 2, Pages 196-208

Radio-over-fiber using an optical antenna based on Rydberg states of atoms

NASA Astrophysics Data System (ADS)

Deb, A. B.; Kjærgaard, N.

2018-05-01

We provide an experimental demonstration of a direct fiber-optic link for RF transmission ("radio-over-fiber") using a sensitive optical antenna based on a rubidium vapor cell. The scheme relies on measuring the transmission of laser light at an electromagnetically induced transparency resonance that involves highly excited Rydberg states. By dressing pairs of Rydberg states using microwave fields that act as local oscillators, we encoded RF signals in the optical frequency domain. The light carrying the information is linked via a virtually lossless optical fiber to a photodetector where the signal is retrieved. We demonstrate a signal bandwidth in excess of 1 MHz limited by the available coupling laser power and atomic optical density. Our sensitive, non-metallic and readily scalable optical antenna for microwaves allows extremely low-levels of optical power (˜1 μW) throughput in the fiber-optic link. It offers a promising future platform for emerging wireless network infrastructures.

Spectroscopy of the three-photon laser excitation of cold Rubidium Rydberg atoms in a magneto-optical trap

DOE Office of Scientific and Technical Information (OSTI.GOV)

Entin, V. M.; Yakshina, E. A.; Tretyakov, D. B.

2013-05-15

The spectra of the three-photon laser excitation 5S{sub 1/2} {yields} 5P{sub 3/2} {yields} 6S{sub 1/2}nP of cold Rb Rydberg atoms in an operating magneto-optical trap based on continuous single-frequency lasers at each stage are studied. These spectra contain two partly overlapping peaks of different amplitudes, which correspond to coherent three-photon excitation and incoherent three-step excitation due to the presence of two different ways of excitation through the dressed states of intermediate levels. A four-level theoretical model based on optical Bloch equations is developed to analyze these spectra. Good agreement between the experimental and calculated data is achieved by introducing additionalmore » decay of optical coherence induced by a finite laser line width and other broadening sources (stray electromagnetic fields, residual Doppler broadening, interatomic interactions) into the model.« less

Laser spectroscopy of the 5P3/2 → 6Pj (j = 1/2 and 3/2) electric dipole forbidden transitions in atomic rubidium

NASA Astrophysics Data System (ADS)

Ponciano-Ojeda, F.; Hernández-Gómez, S.; Mojica-Casique, C.; Hoyos, L. M.; Flores-Mijangos, J.; Ramírez-Martínez, F.; Sahagún, D.; Jáuregui, R.; Jiménez-Mier, J.

2018-04-01

Doppler-free optical double-resonance spectroscopy is used to study the 5S1/2 → 5P3/2 → 6Pj (j = 3/2,1/2) excitation sequence in room-temperature rubidium atoms. This involves a 5S1/2 → 5P3/2 electric dipole preparation step followed by the 5P3/2 → 6Pj electric quadrupole excitation. The electric dipole forbidden transitions occur at 911.0 nm (j = 3/2) and 917.5 nm (j = 1/2). Production of atoms in the 6Pj states is detected by observing their direct decay to the ground state through emission of blue photons (λ ≈ 420 nm). A detailed experimental and theoretical study of the dependence on the relative linear polarizations of excitation beams is made. It is shown that specific electric quadrupole selection rules over magnetic quantum numbers are directly related to the relative orientation of the linear polarization of the excitation beams.

Miniature atomic scalar magnetometer for space based on the rubidium isotope 87Rb.

PubMed

Korth, Haje; Strohbehn, Kim; Tejada, Francisco; Andreou, Andreas G; Kitching, John; Knappe, Svenja; Lehtonen, S John; London, Shaughn M; Kafel, Matiwos

2016-08-01

A miniature atomic scalar magnetometer based on the rubidium isotope 87 Rb was developed for operation in space. The instrument design implements both M x and M z mode operation and leverages a novel microelectromechanical system (MEMS) fabricated vapor cell and a custom silicon-on-sapphire (SOS) complementary metal-oxide-semiconductor (CMOS) integrated circuit. The vapor cell has a volume of only 1 mm 3 so that it can be efficiently heated to its operating temperature by a specially designed, low-magnetic-field-generating resistive heater implemented in multiple metal layers of the transparent sapphire substrate of the SOS-CMOS chips. The SOS-CMOS chip also hosts the Helmholtz coil and associated circuitry to stimulate the magnetically sensitive atomic resonance and temperature sensors. The prototype instrument has a total mass of fewer than 500 g and uses less than 1 W of power, while maintaining a sensitivity of 15 pT/√Hz at 1 Hz, comparable to present state-of-the-art absolute magnetometers.

Crystal structure of rubidium methyl-diazo-tate.

PubMed

Grassl, Tobias; Korber, Nikolaus

2017-02-01

The title compound, Rb + ·H 3 CN 2 O - , has been crystallized in liquid ammonia as a reaction product of the reductive ammonolysis of the natural compound streptozocin. Elemental rubidium was used as reduction agent as it is soluble in liquid ammonia, forming a blue solution. Reductive bond cleavage in biogenic materials under kinetically controlled conditions offers a new approach to gain access to sustainably produced raw materials. The anion is nearly planar [dihedral angle O-N-N-C = -0.4 (2)°]. The Rb + cation has a coordination number of seven, and coordinates to five anions. One anion is bound via both its N atoms, one by both O and N, two anions are bound by only their O atoms, and the last is bound via the N atom adjacent to the methyl group. The diazo-tate anions are bridged by cations and do not exhibit any direct contacts with each other. The cations form corrugated layers that propagate in the (-101) plane.

A multi-channel tunable source for atomic sensors

NASA Astrophysics Data System (ADS)

Bigelow, Matthew S.; Roberts, Tony D.; McNeil, Shirley A.; Hawthorne, Todd; Battle, Phil

2015-09-01

We have designed and completed initial testing on a laser source suitable for atomic interferometry from compact, robust, integrated components. Our design is enabled by capitalizing on robust, well-commercialized, low-noise telecom components with high reliability and declining costs which will help to drive the widespread deployment of this system. The key innovation is the combination of current telecom-based fiber laser and modulator technology with periodicallypoled waveguide technology to produce tunable laser light at rubidium D1 and D2 wavelengths (and expandable to other alkalis) using second harmonic generation (SHG). Unlike direct-diode sources, this source is immune to feedback at the Rb line eliminating the need for bulky high-power isolators in the system. In addition, the source has GHz-level frequency agility and in our experiments was found to only be limited by the agility of our RF generator. As a proof-of principle, the source was scanned through the Doppler-broadened Rb D2 absorption line. With this technology, multiple channels can be independently tuned to produce the fields needed for addressing atomic states in atom interferometers and clocks. Thus, this technology could be useful in the development cold-atom inertial sensors and gyroscopes.

Gradient Echo Quantum Memory in Warm Atomic Vapor

PubMed Central

Pinel, Olivier; Hosseini, Mahdi; Sparkes, Ben M.; Everett, Jesse L.; Higginbottom, Daniel; Campbell, Geoff T.; Lam, Ping Koy; Buchler, Ben C.

2013-01-01

Gradient echo memory (GEM) is a protocol for storing optical quantum states of light in atomic ensembles. The primary motivation for such a technology is that quantum key distribution (QKD), which uses Heisenberg uncertainty to guarantee security of cryptographic keys, is limited in transmission distance. The development of a quantum repeater is a possible path to extend QKD range, but a repeater will need a quantum memory. In our experiments we use a gas of rubidium 87 vapor that is contained in a warm gas cell. This makes the scheme particularly simple. It is also a highly versatile scheme that enables in-memory refinement of the stored state, such as frequency shifting and bandwidth manipulation. The basis of the GEM protocol is to absorb the light into an ensemble of atoms that has been prepared in a magnetic field gradient. The reversal of this gradient leads to rephasing of the atomic polarization and thus recall of the stored optical state. We will outline how we prepare the atoms and this gradient and also describe some of the pitfalls that need to be avoided, in particular four-wave mixing, which can give rise to optical gain. PMID:24300586

Gradient echo quantum memory in warm atomic vapor.

PubMed

Pinel, Olivier; Hosseini, Mahdi; Sparkes, Ben M; Everett, Jesse L; Higginbottom, Daniel; Campbell, Geoff T; Lam, Ping Koy; Buchler, Ben C

2013-11-11

Gradient echo memory (GEM) is a protocol for storing optical quantum states of light in atomic ensembles. The primary motivation for such a technology is that quantum key distribution (QKD), which uses Heisenberg uncertainty to guarantee security of cryptographic keys, is limited in transmission distance. The development of a quantum repeater is a possible path to extend QKD range, but a repeater will need a quantum memory. In our experiments we use a gas of rubidium 87 vapor that is contained in a warm gas cell. This makes the scheme particularly simple. It is also a highly versatile scheme that enables in-memory refinement of the stored state, such as frequency shifting and bandwidth manipulation. The basis of the GEM protocol is to absorb the light into an ensemble of atoms that has been prepared in a magnetic field gradient. The reversal of this gradient leads to rephasing of the atomic polarization and thus recall of the stored optical state. We will outline how we prepare the atoms and this gradient and also describe some of the pitfalls that need to be avoided, in particular four-wave mixing, which can give rise to optical gain.

Atom Interferometry in a Warm Vapor

DOE PAGES

Biedermann, G. W.; McGuinness, H. J.; Rakholia, A. V.; ...

2017-04-17

Here, we demonstrate matter-wave interference in a warm vapor of rubidium atoms. Established approaches to light-pulse atom interferometry rely on laser cooling to concentrate a large ensemble of atoms into a velocity class resonant with the atom optical light pulse. In our experiment, we show that clear interference signals may be obtained without laser cooling. This effect relies on the Doppler selectivity of the atom interferometer resonance. Lastly, this interferometer may be configured to measure accelerations, and we demonstrate that multiple interferometers may be operated simultaneously by addressing multiple velocity classes.

Resonance dispersion interaction of alkali metal atoms in Rydberg states

NASA Astrophysics Data System (ADS)

Kamenski, A. A.; Mokhnenko, S. N.; Ovsyannikov, V. D.

2017-06-01

With the use of second-order perturbation theory in the long-range interatomic interaction for the degenerate states of two Rydberg atoms we have obtained a general formula for the dependence of atomic interaction energy on the interatomic distance R in the presence of the Förster resonance. Inside of the ‘Förster sphere’ (R < RF) this dependence transforms to the formula for electric dipole interaction energy ΔEd - d = C3/R3 and for R > RF it transforms to the formula for the van der Waals interaction energy ΔEVdW = -C6/R6. The van der Waals constant C6 is represented as an expansion in terms of irreducible components which define the dependence on the interatomic axis orientation relative to the quantisation axis of projections M of the total angular momentum J. The numerical values of the irreducible components of tensor C6 were calculated for rubidium atoms in the same Rydberg states |nlJM> with large quantum numbers n. We present the calculated resonance interaction energy of two rubidium atoms in the states |43D5/2M>, whose total energy exceeds by only 8 MHz the total energy of one of the atoms in the state |45P3/2M> and of the other in the state |41F7/2M>.

Mineral Commodity Profiles -- Rubidium

USGS Publications Warehouse

Butterman, W.C.; Reese, R.G.

2003-01-01

Overview -- Rubidium is a soft, ductile, silvery-white metal that melts at 39.3 ?C. One of the alkali metals, it is positioned in group 1 (or IA) of the periodic table between potassium and cesium. Naturally occurring rubidium is slightly radioactive. Rubidium is an extremely reactive metal--it ignites spontaneously in the presence of air and decomposes water explosively, igniting the liberated hydrogen. Because of its reactivity, the metal and several of its compounds are hazardous materials, and must be stored and transported in isolation from possible reactants. Although rubidium is more abundant in the earth?s crust than copper, lead, or zinc, it forms no minerals of its own, and is, or has been, produced in small quantities as a byproduct of the processing of cesium and lithium ores taken from a few small deposits in Canada, Namibia, and Zambia. In the United States, the metal and its compounds are produced from imported raw materials by at least one company, the Cabot Corporation (Cabot, 2003). Rubidium is used interchangeably or together with cesium in many uses. Its principal application is in specialty glasses used in fiber optic telecommunication systems. Rubidium?s photoemissive properties have led to its use in night-vision devices, photoelectric cells, and photomultiplier tubes. It has several uses in medical science, such as in positron emission tomographic (PET) imaging, the treatment of epilepsy, and the ultracentrifugal separation of nucleic acids and viruses. A dozen or more other uses are known, which include use as a cocatalyst for several organic reactions and in frequency reference oscillators for telecommunications network synchronization. The market for rubidium is extremely small, amounting to 1 to 2 metric tons per year (t/yr) in the United States. World resources are vast compared with demand.

Absolute frequency measurement of a diode laser locked on a hyperfine component of 5S1/2-5D5/2 two-photon transitions of rubidium (lambda equals 778.1 nm, nu equals 385.3 THz)

NASA Astrophysics Data System (ADS)

Zondy, Jean-Jacques; Touahri, D.; Acef, Ouali; Hilico, L.; Abed, M.; Clairon, Andre; Millerioux, Yves P.; Felder, Raymond; de Beauvoir, Beatrice; Nez, Francois; Biraben, Francois; Julien, Lucile

1995-04-01

A frequency chain, derived from the one used to measure the absolute frequency ((nu) $= 473 THz) of the He-Ne/I2 optical standard, is currently being implemented in order to measure the frequency of a diode laser stabilized on the two-photon transition of rubidium vapor. The measurement scheme is based on the comparison of the frequency of this near-IR potential secondary standard to the 13th harmonic frequency of the R(12)-CO2/OsO4 LPTF secondary standard at (nu) equals 29.096 THz. Recent results on the frequency synthesis are reported, enabling the testing of long-term stability of this Rb-locked system with respect to the IR reference standard.

Elimination of the light shift in rubidium gas cell frequency standards using pulsed optical pumping

NASA Technical Reports Server (NTRS)

English, T. C.; Jechart, E.; Kwon, T. M.

1978-01-01

Changes in the intensity of the light source in an optically pumped, rubidium, gas cell frequency standard can produce corresponding frequency shifts, with possible adverse effects on the long-term frequency stability. A pulsed optical pumping apparatus was constructed with the intent of investigating the frequency stability in the absence of light shifts. Contrary to original expectations, a small residual frequency shift due to changes in light intensity was experimentally observed. Evidence is given which indicates that this is not a true light-shift effect. Preliminary measurements of the frequency stability of this apparatus, with this small residual pseudo light shift present, are presented. It is shown that this pseudo light shift can be eliminated by using a more homogeneous C-field. This is consistent with the idea that the pseudo light shift is due to inhomogeneity in the physics package (position-shift effect).

Experimental study of the role of trap symmetry in an atom-chip interferometer above the Bose–Einstein condensation threshold

NASA Astrophysics Data System (ADS)

Dupont-Nivet, M.; Demur, R.; Westbrook, C. I.; Schwartz, S.

2018-04-01

We report the experimental study of an atom-chip interferometer using ultracold rubidium 87 atoms above the Bose–Einstein condensation threshold. The observed dependence of the contrast decay time with temperature and with the degree of symmetry of the traps during the interferometer sequence is in good agreement with theoretical predictions published in Dupont-Nivet et al (2016 New J. Phys. 18 113012). These results pave the way for precision measurements with trapped thermal atoms.

Photon-photon entanglement with a single trapped atom.

PubMed

Weber, B; Specht, H P; Müller, T; Bochmann, J; Mücke, M; Moehring, D L; Rempe, G

2009-01-23

An experiment is performed where a single rubidium atom trapped within a high-finesse optical cavity emits two independently triggered entangled photons. The entanglement is mediated by the atom and is characterized both by a Bell inequality violation of S=2.5, as well as full quantum-state tomography, resulting in a fidelity exceeding F=90%. The combination of cavity-QED and trapped atom techniques makes our protocol inherently deterministic--an essential step for the generation of scalable entanglement between the nodes of a distributed quantum network.

Atomic vapor quantum memory for a photonic polarization qubit.

PubMed

Cho, Young-Wook; Kim, Yoon-Ho

2010-12-06

We report an experimental realization of an atomic vapor quantum memory for the photonic polarization qubit. The performance of the quantum memory for the polarization qubit, realized with electromagnetically-induced transparency in two spatially separated ensembles of warm Rubidium atoms in a single vapor cell, has been characterized with quantum process tomography. The process fidelity better than 0.91 for up to 16 μs of storage time has been achieved.

Shock wave loading of a magnetic guide

NASA Astrophysics Data System (ADS)

Kindt, L.

2011-10-01

The atom laser has long been a holy grail within atom physics and with the creation of an atom laser we hope to bring a similar revolution in to the field of atom optics. With the creation of the Bose-Einstein Condensate (BEC) in 1995 the path to an atom laser was initiated. An atom laser is continues source of BEC. In a Bose condensate all the atoms occupy the same quantum state and can be described by the same wave function and phase. With an atom laser the De Broglie wavelength of atoms can be much smaller than the wavelength of light. Due to the ultimate control over the atoms the atom laser is very interesting for atom optics, lithography, metrology, etching and deposition of atoms on a surface. All previous atom lasers have been created from atoms coupled out from an existing Bose-Einstein Condensate. There are different approaches but common to them all is that the duration of the output of the atom laser is limited by the size of the initial BEC and they all have a low flux. This leaves the quest to build a continuous high flux atom laser. An alternative approach to a continuous BEC beam is to channel a continuous ultra cold atomic beam into a magnetic guide and then cool this beam down to degeneracy. Cooling down a continuous beam of atoms faces three large problems: The collision rate has to be large enough for effective rethermalization, since evaporative cooling in 2D is not as effective as in 3D and a large thermal conductivity due to atoms with a high angular momentum causes heating downstream in the guide. We have built a 4 meter magnetic guide that is placed on a downward slope with a magnetic barrier in the end. In the guide we load packets of ultra cold rubidium atoms with a frequency rate large enough for the packets to merge together to form a continuous atomic beam. The atomic beam is supersonic and when the beam reaches the end barrier it will return and collide with itself. The collisions lowers the velocity of the beam into subsonic velocities and a shock wave is created between the two velocity regions. In order to conserve number of particle, momentum and enthalpy the density of the atomic beam passing through the shock wave must increase. We have build such a shock wave in an atomic beam and observed the density increase due to this. As an extra feature having a subsonic beam on a downward slope adds an extra density increase due to gravitational compression. Loading ultra cold atoms into a 3D trap from the dense subsonic beam overcomes the problem with 2D cooling and thermal conductivity. This was done and evaporative cooling was applied creating an unprecedented large number rubidium BEC.

Frequency Standards and Metrology

NASA Astrophysics Data System (ADS)

Maleki, Lute

2009-04-01

Preface / Lute Maleki -- Symposium history / Jacques Vanier -- Symposium photos -- pt. I. Fundamental physics. Variation of fundamental constants from the big bang to atomic clocks: theory and observations (Invited) / V. V. Flambaum and J. C. Berengut. Alpha-dot or not: comparison of two single atom optical clocks (Invited) / T. Rosenband ... [et al.]. Variation of the fine-structure constant and laser cooling of atomic dysprosium (Invited) / N. A. Leefer ... [et al.]. Measurement of short range forces using cold atoms (Invited) / F. Pereira Dos Santos ... [et al.]. Atom interferometry experiments in fundamental physics (Invited) / S. W. Chiow ... [et al.]. Space science applications of frequency standards and metrology (Invited) / M. Tinto -- pt. II. Frequency & metrology. Quantum metrology with lattice-confined ultracold Sr atoms (Invited) / A. D. Ludlow ... [et al.]. LNE-SYRTE clock ensemble: new [symbol]Rb hyperfine frequency measurement - spectroscopy of [symbol]Hg optical clock transition (Invited) / M. Petersen ... [et al.]. Precise measurements of S-wave scattering phase shifts with a juggling atomic clock (Invited) / S. Gensemer ... [et al.]. Absolute frequency measurement of the [symbol] clock transition (Invited) / M. Chwalla ... [et al.]. The semiclassical stochastic-field/atom interaction problem (Invited) / J. Camparo. Phase and frequency noise metrology (Invited) / E. Rubiola ... [et al.]. Optical spectroscopy of atomic hydrogen for an improved determination of the Rydberg constant / J. L. Flowers ... [et al.] -- pt. III. Clock applications in space. Recent progress on the ACES mission (Invited) / L. Cacciapuoti and C. Salomon. The SAGAS mission (Invited) / P. Wolf. Small mercury microwave ion clock for navigation and radioScience (Invited) / J. D. Prestage ... [et al.]. Astro-comb: revolutionizing precision spectroscopy in astrophysics (Invited) / C. E. Kramer ... [et al.]. High frequency very long baseline interferometry: frequency standards and imaging an event horizon (Invited) / S. Doeleman. Optically-pumped space cesium clock for Galileo: results of the breadboard / R. Ruffieux ... [et al.] -- pt. IV. Optical clocks I: lattice clocks. Optical lattice clock: seven years of progress and next steps (Invited) / H. Katori, M. Takamoto and T. Akatsuka. The Yb optical lattice clock (Invited) / N. D. Demke ... [et al.]. Optical Lattice clock with Sr atoms (Invited) / P. G. Westergaard ... [et al.]. Development of an optical clock based on neutral strontium atoms held in a lattice trap / E. A. Curtis ... [et al.]. Decoherence and losses by collisions in a [symbol]Sr lattice clock / J. S. R. Vellore Winfred ... [et al.]. Lattice Yb optical clock and cryogenic Cs fountain at INRIM / F. Levi ... [et al.] -- pt. V. Optical clocks II: ion clocks. [Symbol]Yb+ single-ion optical frequency standards (Invited) / Chr. Tamm ... [et al.]. An optical clock based on a single trapped [symbol]Sr+ ion (Invited) / H. S. Margolis ... [et al.]. A trapped [symbol]Yb+ ion optical frequency standard based on the [symbol] transition (Invited) / P. Gill ... [et al.]. Overview of highly accurate RF and optical frequency standards at the National Research Council of Canada (Invited) / A. A. Madej ... [et al.] -- pt. VI. Optical frequency combs. Extreme ultraviolet frequency combs for spectroscopy (Invited) / A. Ozawa ... [et al.]. Development of an optical clockwork for the single trapped strontium ion standard at 445 THz / J. E. Bernard ... [et al.]. A phase-coherent link between the visible and infrared spectral ranges using a combination of CW OPO and femtosecond laser frequency comb / E. V. Kovalchuk and A. Peters. Improvements to the robustness of a TI: sapphire-based femtosecond comb at NPL / V. Tsatourian ... [et al.] -- pt. VII. Atomic microwave standards. NIST FI and F2 (Invited) / T. P. Heavner ... [et al.]. Atomic fountains for the USNO master clock (Invited) / C. Ekstrom ... [et al.]. The transportable cesium fountain clock NIM5: its construction and performance (Invited) / T. Li ... [et al.].Compensated multi-pole mercury trapped ion frequency standard and stability evaluation of systematic effects (Invited) / E. A. Burt ... [et al.]. Research of frequency standards in SIOM - atomic frequency standards based on coherent storage (Invited) / B. Yan ... [et al.]. The PTB fountain clock ensemble preliminary characterization of the new fountain CSF2 / N. Nemitz ... [et al.]. The pulsed optically pumped clock: microwave and optical detection / S. Micalizio ... [et al.]. Research on characteristics of pulsed optically pumped rubidium frequency standard / J. Deng ... [et al.]. Status of the continuous cold fountain clocks at METAS-LTF / A. Joyet ... [et al.]. Experiments with a new [symbol]Hg+ ion clock / E. A. Burt ... [et al.]. Optimising a high-stability CW laser-pumped rubidium gas-cell frequency standard / C. Affolderbach ... [et al.]. Raman-Ramsey Cs cell atomic clock / R. Boudot ... [et al.] -- pt. VIII. Microwave resonators & oscillators. Solutions and ultimate limits in temperature compensation of metallic cylindrical microwave resonators (Invited) / A. De Marchi. Cryogenic sapphire oscillators (Invited) / J. G. Hartnett, E. N. Ivanov and M. E. Tobar. Ultra-stable optical cavity: design and experiments / J. Millo ... [et al.]. New results for whispering gallery mode cryogenic sapphire maser oscillators / K. Benmessai ... [et al.] -- pt. IX. Advanced techniques. Fundamental noise-limited optical phase locking at Femtowatt light levels (Invited) / J. Dick ... [et al.]. Microwave and optical frequency transfer via optical fibre / G. Marra ... [et al.]. Ultra-stable laser source for the [symbol]Sr+ single-ion optical frequency standard at NRC / P. Dubé, A. A. Madej and J. E. Bernard. Clock laser system for a strontium lattice clock / T. Legero ... [et al.]. Measurement noise floor for a long-distance optical carrier transmission via fiber / G. Grosche ... [et al.]. Optical frequency transfer over 172 KM of installed fiber / S. Crane -- pt. X. Miniature systems. Chip-scale atomic devices: precision atomic instruments based on MEMS (Invited) / J. Kitching ... [et al.]. CSAC - the chip-scale atomic clock (Invited) / R. Lutwak ... [et al.]. Reaching a few 10[symbol] stability level with a compact cold atom clock / F. X. Esnault ... [et al.]. Evaluation of Lin||Lin CPT for compact and high performance frequency standard / E. Breschi ... [et al.] -- pt. XI. Time scales. Atomic time scales TAI and TI(BIPM): present status and prospects (Invited) / G. Petit. Weight functions for biases in atomic frequency standards / J. H. Shirley -- pt. XII. Interferometers. Definition and construction of noise budget in atom interferometry (Invited) / E. D'Ambriosio. Characterization of a cold atom gyroscope (Invited) / A. Landragin ... [et al.]. A mobile atom interferometer for high precision measurements of local gravity / M. Schmidt ... [et al.]. Demonstration of atom interferometer comprised of geometric beam splitters / Hiromitsu Imai and Atsuo Morinaga -- pt. XIII. New directions. Active optical clocks (Invited) / J. Chen. Prospects for a nuclear optical frequency standard based on Thorium-229 (Invited) / E. Peik ... [et al.]. Whispering gallery mode oscillators and optical comb generators (Invited) / A. B. Matsko ... [et al.]. Frequency comparison using energy-time entangled photons / A. Stefanov -- List of participants.

Polarization effects in the interaction between multi-level atoms and two optical fields

NASA Astrophysics Data System (ADS)

Colín-Rodríguez, R.; Flores-Mijangos, J.; Hernández-Gómez, S.; Jáuregui, R.; López-Hernández, O.; Mojica-Casique, C.; Ponciano-Ojeda, F.; Ramírez-Martínez, F.; Sahagún, D.; Volke-Sepúlveda, K.; Jiménez-Mier, J.

2015-06-01

Polarized velocity selective spectra for rubidium atoms in a room temperature cell are presented. The experiments were performed in the lambda configuration (D2 manifold) and in the 5s\\to 5{{p}3/2}\\to 5{{d}j} ladder configuration. For the lambda configuration the effect of the probe beam intensity in the absorption and polarization spectra are compared with results of a rate equation approximation. Good overall agreement between experiment and theory is found. The results indicate different saturation rates for each of the atomic transitions. Distinctive polarization signals with hyperfine-resolved components are found for the ladder 5{{d}3/2} and 5{{d}5/2} upper states. Fluorescence detection of the 420 nm that results from the second step in the cascade decay 5{{d}j}\\to 6{{p}{{j\\prime }}}\\to 5s was used in the ladder experiments. This fluorescence was also used for the detection of the 5{{p}3/2}\\to 6{{p}3/2} electric dipole forbidden transition in atomic rubidium that occurs at 911 nm. The 6{{p}3/2} hyperfine structure was resolved in this continuous wave, non-dipole excitation.

Synthesis of perbromates

NASA Technical Reports Server (NTRS)

Appelman, E. H.; Studier, M. H.

1969-01-01

Salts of heptavalent bromine were synthesized by a hot atom process, the beta decay of radioactive selenium-83 incorporated into a selenate. Formation of an unreactive perbromate ion led to preparation of macro amounts of perborate. A rubidium salt was isolated.

Ultracold Realization of AntiFerromagenteic Order

NASA Astrophysics Data System (ADS)

Shrestha, Uttam

2011-03-01

We investigate numerically the experimental feasibility of observing the antiferromagnetic (AF) order in the bosonic mixtures of rubidium (87 Rb) and potassium (41 K) in a two-dimensional optical lattice with external trapping potential. Within the mean-field approximation we have found the ground states which, for a specific range of parameters such as inter-species interactions and lattice height, interpolate from phase separation to the AF order. For the moderate lattice heights the coexistence of the Mott and AF phase is possible for rubidium atoms while the potassium atoms remain superfluid with overlapped AF phase. In our view there has not been any study on AF order in two-component systems when one component remains in the superfluid phase while the other is in the Mott phase. Therefore, this observation may provide a novel regime for studying quantum magnetism in ultracold systems. This work was supported by the EU Contract EU STREP NAMEQUAM.

NMR Knight shifts and the electronic properties of Rb{sub 8}Na{sub 16}Si{sub 136} clathrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Latturner, Susan; Iversen, Bo B.; Sepa, Jelena

2001-03-15

A silicon framework clathrate type-II compound was synthesized with rubidium and sodium atoms in cages. A single crystal of this material was characterized by both conventional and synchrotron x-ray diffraction; the structure belongs to the cubic space group Fd-3m, with a cell edge of 14.738(1) Aa. The alkali metals are ordered in the structure, with the small cages containing sodium, and the large cages containing rubidium. Variable temperature magic-angle-spinning NMR of all three nuclei show large Knight shifts with a strong temperature dependence, unlike conventional metals. The low conductivity (200 S/cm) and high paramagnetic susceptibility (5x10{sup -6}emu/g) indicate that asmore » the temperature is lowered, the electrons become more localized on the alkali atoms, resulting in properties consistent with a correlated narrow band metal system.« less

Analyses of absorption distribution of a rubidium cell side-pumped by a Laser-Diode-Array (LDA)

NASA Astrophysics Data System (ADS)

Yu, Hang; Han, Juhong; Rong, Kepeng; Wang, Shunyan; Cai, He; An, Guofei; Zhang, Wei; Yu, Qiang; Wu, Peng; Wang, Hongyuan; Wang, You

2018-01-01

A diode-pumped alkali laser (DPAL) has been regarded as one of the most potential candidates to achieve high power performances of next generation. In this paper, we investigate the physical properties of a rubidium cell side-pumped by a Laser-Diode-Array (LDA) in this study. As the saturated concentration of a gain medium inside a vapor cell is extremely sensitive to the temperature, the populations of every energy-level of the atomic alkali are strongly relying on the vapor temperature. Thus, the absorption characteristics of a DPAL are mainly dominated by the temperature distribution. In this paper, the temperature, absorption, and lasing distributions in the cross-section of a rubidium cell side-pumped by a LDA are obtained by means of a complicated mathematic procedure. Based on the original end-pumped mode we constructed before, a novel one-direction side-pumped theoretical mode has been established to explore the distribution properties in the transverse section of a rubidium vapor cell by combining the procedures of heat transfer and laser kinetics together. It has been thought the results might be helpful for design of a side-pumped configuration in a high-powered DPAL.

First international comparison of fountain primary frequency standards via a long distance optical fiber link

NASA Astrophysics Data System (ADS)

Guéna, J.; Weyers, S.; Abgrall, M.; Grebing, C.; Gerginov, V.; Rosenbusch, P.; Bize, S.; Lipphardt, B.; Denker, H.; Quintin, N.; Raupach, S. M. F.; Nicolodi, D.; Stefani, F.; Chiodo, N.; Koke, S.; Kuhl, A.; Wiotte, F.; Meynadier, F.; Camisard, E.; Chardonnet, C.; Le Coq, Y.; Lours, M.; Santarelli, G.; Amy-Klein, A.; Le Targat, R.; Lopez, O.; Pottie, P. E.; Grosche, G.

2017-06-01

We report on the first comparison of distant caesium fountain primary frequency standards (PFSs) via an optical fiber link. The 1415 km long optical link connects two PFSs at LNE-SYRTE (Laboratoire National de métrologie et d’Essais—SYstème de Références Temps-Espace) in Paris (France) with two at PTB (Physikalisch-Technische Bundesanstalt) in Braunschweig (Germany). For a long time, these PFSs have been major contributors to accuracy of the International Atomic Time (TAI), with stated accuracies of around 3× {{10}-16} . They have also been the references for a number of absolute measurements of clock transition frequencies in various optical frequency standards in view of a future redefinition of the second. The phase coherent optical frequency transfer via a stabilized telecom fiber link enables far better resolution than any other means of frequency transfer based on satellite links. The agreement for each pair of distant fountains compared is well within the combined uncertainty of a few 10-16 for all the comparisons, which fully supports the stated PFSs’ uncertainties. The comparison also includes a rubidium fountain frequency standard participating in the steering of TAI and enables a new absolute determination of the 87Rb ground state hyperfine transition frequency with an uncertainty of 3.1× {{10}-16} . This paper is dedicated to the memory of André Clairon, who passed away on 24 December 2015, for his pioneering and long-lasting efforts in atomic fountains. He also pioneered optical links from as early as 1997.

Diode Laser Velocity Measurements by Modulated Filtered Rayleigh Scattering

NASA Technical Reports Server (NTRS)

Mach, J. J.; Varghese, P. L.; Jagodzinski, J. J.

1999-01-01

The ability of solid-state lasers to be tuned in operating frequency at MHz rates by input current modulation, while maintaining a relatively narrow line-width, has made them useful for spectroscopic measurements. Their other advantages include low cost, reliability, durability, compact size, and modest power requirements, making them a good choice for a laser source in micro-gravity experiments in drop-towers and in flight. For their size, they are also very bright. In a filtered Rayleigh scattering (FRS) experiment, a diode laser can be used to scan across an atomic or molecular absorption line, generating large changes in transmission at the resonances for very small changes in frequency. The hyperfine structure components of atomic lines of alkali metal vapors are closely spaced and very strong, which makes such atomic filters excellent candidates for sensitive Doppler shift detection and therefore for high-resolution velocimetry. In the work we describe here we use a Rubidium vapor filter, and work with the strong D(sub 2) transitions at 780 nm that are conveniently accessed by near infrared diode lasers. The low power output of infrared laser diodes is their primary drawback relative to other laser systems commonly used for velocimetry. However, the capability to modulate the laser frequency rapidly and continuously helps mitigate this. Using modulation spectroscopy and a heterodyne detection scheme with a lock-in amplifier, one can extract sub-microvolt signals occurring at a specific frequency from a background that is orders of magnitude stronger. The diode laser modulation is simply achieved by adding a small current modulation to the laser bias current. It may also be swept repetitively in wavelength using an additional lower frequency current ramp.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Selective reflection of obliquely incident polarised light

NASA Astrophysics Data System (ADS)

Fofanov, Ya A.

2009-06-01

A series of reflection resonances formed by the hyperfine components of the D2-lines in the spectrum of the natural mixture of rubidium isotopes is studied. Passages from resonantly frustrated total internal reflection to resonance Brewster reflection caused by the frequency tuning of the incident light are demonstrated experimentally. The contrast of the strongest refection resonances exceeds 500% at the moderate heating of reflecting cells. The intensity of the reflected light changes in this case by more than 20 times. A theory is developed which is based on a two-level model for resonance atoms and Fresnel formulas for reflection coefficients. Numerical calculations based on the proposed theory confirm main experimental results.

Laser cooling of rubidium atoms in a 2D optical lattice

NASA Astrophysics Data System (ADS)

Wei, Chunhua; Kuhn, Carlos C. N.

2018-06-01

Lossless polarization gradient cooling of ?? atoms in a far-detuned 2D optical lattice is demonstrated. Temperatures down to ?K and phase space densities as high as 1 / 1000 are achieved in a total duty cycle of ?. It is shown that utilizing the vector component of the optical lattice allows lower temperatures to be achieved when compared with pure scalar lattices.

Photoionization bands of rubidium molecule

NASA Astrophysics Data System (ADS)

Rakić, M.; Pichler, G.

2018-03-01

We studied the absorption spectrum of dense rubidium vapor generated in a T-type sapphire cell with a special emphasis on the structured photoionization continuum observed in the 200-300 nm spectral region. The photoionization spectrum has a continuous atomic contribution with a pronounced Seaton-Cooper minimum at about 250 nm and a molecular photoionization contribution with many broad bands. We discuss the possible origin of the photoionization bands as stemming from the absorption from the ground state of the Rb2 molecule to excited states of Rb2+* and to doubly excited autoionizing states of Rb2** molecule. All these photoionization bands are located above the Rb+ and Rb2+ ionization limits.

Two-photon transitions driven by a combination of diode and femtosecond lasers.

PubMed

Moreno, Marco P; Nogueira, Giovana T; Felinto, Daniel; Vianna, Sandra S

2012-10-15

We report on the combined action of a cw diode laser and a train of ultrashort pulses when each of them drives one step of the 5S-5P-5D two-photon transition in rubidium vapor. The fluorescence from the 6P(3/2) state is detected for a fixed repetition rate of the femtosecond laser while the cw-laser frequency is scanned over the rubidium D(2) lines. This scheme allows for a velocity selective spectroscopy in a large spectral range including the 5D(3/2) and 5D(5/2) states. The results are well described in a simplified frequency domain picture, considering the interaction of each velocity group with the cw laser and a single mode of the frequency comb.

An ultra-stable optical frequency standard for telecommunication purposes based upon the 5S1/2 → 5D5/2 two-photon transition in rubidium

NASA Astrophysics Data System (ADS)

Terra, Osama; Hussein, Hatem

2016-02-01

In this study, we report the development of a frequency standard for optical fiber communication applications based on a two-photon transition in rubidium at 385.2 THz. This standard kills two birds with one stone in the sense it is capable of providing us with two highly stable serviceable wavelengths at 778.1 and 1556.2 nm. In this system, we exploit the narrow line-width of a fiber laser emitting at 1556.2 nm in conjunction with an erbium-doped fiber amplifier to generate a sufficient second harmonic laser beam at 778.1 nm in a periodically polled lithium niobate waveguide mixer in order to probe and frequency-lock the laser to the 5S1/2 ( F g = 3)-5D5/2 ( F e = 5) hyperfine two-photon transition component in 85Rb. The metrological performance of the standard is evaluated with the aid of an optical frequency comb synthesizer. Allan variance measurement shows a stability of 4 × 10-12 at 1 s (limited by the comb stability), reaching a floor of 6.8 × 10-13 at 1000 s. After correction of all the major systematic frequency shifts including the light shift, the absolute frequency is found to be 385 285 142 374.0 (5.0) kHz. Moreover, the absolute frequencies of most of the hyperfine components of the 5S1/2-5D5/2 transition of the two naturally existing rubidium isotopes are measured using a femtosecond frequency comb synthesizer after stabilizing a laser on each component.

Rubidium distribution at atomic scale in high efficient Cu(In,Ga)Se2 thin-film solar cells

NASA Astrophysics Data System (ADS)

Vilalta-Clemente, Arantxa; Raghuwanshi, Mohit; Duguay, Sébastien; Castro, Celia; Cadel, Emmanuel; Pareige, Philippe; Jackson, Philip; Wuerz, Roland; Hariskos, Dimitrios; Witte, Wolfram

2018-03-01

The introduction of a rubidium fluoride post deposition treatment (RbF-PDT) for Cu(In,Ga)Se2 (CIGS) absorber layers has led to a record efficiency up to 22.6% for thin-film solar cell technology. In the present work, high efficiency CIGS samples with RbF-PDT have been investigated by atom probe tomography (APT) to reveal the atomic distribution of all alkali elements present in CIGS layers and compared with non-treated samples. A Scanning Electron Microscopy Dual beam station (Focused Ion Beam-Gas Injection System) as well as Transmission Kikuchi diffraction is used for atom probe sample preparation and localization of the grain boundaries (GBs) in the area of interest. The analysis of the 3D atomic scale APT reconstructions of CIGS samples with RbF-PDT shows that inside grains, Rb is under the detection limit, but the Na concentration is enhanced as compared to the reference sample without Rb. At the GBs, a high concentration of Rb reaching 1.5 at. % was found, and Na and K (diffusing from the glass substrate) are also segregated at GBs but at lower concentrations as compared to Rb. The intentional introduction of Rb leads to significant changes in the chemical composition of CIGS matrix and at GBs, which might contribute to improve device efficiency.

Site-Resolved Imaging with the Fermi Gas Microscope

NASA Astrophysics Data System (ADS)

Huber, Florian Gerhard

The recent development of quantum gas microscopy for bosonic rubidium atoms trapped in optical lattices has made it possible to study local structure and correlations in quantum many-body systems. Quantum gas microscopes are a perfect platform to perform quantum simulation of condensed matter systems, offering unprecedented control over both internal and external degrees of freedom at a single-site level. In this thesis, this technique is extended to fermionic particles, paving the way to fermionic quantum simulation, which emulate electrons in real solids. Our implementation uses lithium, the lightest atom amenable to laser cooling. The absolute timescales of dynamics in optical lattices are inversely proportional to the mass. Therefore, experiments are more than six times faster than for the only other fermionic alkali atom, potassium, and more then fourteen times faster than an equivalent rubidium experiment. Scattering and collecting a sufficient number of photons with our high-resolution imaging system requires continuous cooling of the atoms during the fluorescence imaging. The lack of a resolved excited hyperfine structure on the D2 line of lithium prevents efficient conventional sub-Doppler cooling. To address this challenge we have applied a Raman sideband cooling scheme and achieved the first site-resolved imaging of ultracold fermions in an optical lattice.

The ac stark shift and space-borne rubidium atomic clocks

NASA Astrophysics Data System (ADS)

Formichella, V.; Camparo, J.; Sesia, I.; Signorile, G.; Galleani, L.; Huang, M.; Tavella, P.

2016-11-01

Due to its small size, low weight, and low power consumption, the Rb atomic frequency standard (RAFS) is routinely the first choice for atomic timekeeping in space. Consequently, though the device has very good frequency stability (rivaling passive hydrogen masers), there is interest in uncovering the fundamental processes limiting its long-term performance, with the goal of improving the device for future space systems and missions. The ac Stark shift (i.e., light shift) is one of the more likely processes limiting the RAFS' long-term timekeeping ability, yet its manifestation in the RAFS remains poorly understood. In part, this comes from the fact that light-shift induced frequency fluctuations must be quantified in terms of the RAFS' light-shift coefficient and the output variations in the RAFS' rf-discharge lamp, which is a nonlinear inductively-couple plasma (ICP). Here, we analyze the light-shift effect for a family of 10 on-orbit Block-IIR GPS RAFS, examining decade-long records of their on-orbit frequency and rf-discharge lamp fluctuations. We find that the ICP's light intensity variations can take several forms: deterministic aging, jumps, ramps, and non-stationary noise, each of which affects the RAFS' frequency via the light shift. Correlating these light intensity changes with RAFS frequency changes, we estimate the light-shift coefficient, κLS, for the family of RAFS: κLS = -(1.9 ± 0.3) × 10-12/%. The 16% family-wide variation in κLS indicates that while each RAFS may have its own individual κLS, the variance of κLS among similarly designed RAFS can be relatively small. Combining κLS with our estimate of the ICP light intensity's non-stationary noise, we find evidence that random-walk frequency noise in high-quality space-borne RAFS is strongly influenced by the RAFS' rf-discharge lamp via the light shift effect.

Hybrid Systems: Cold Atoms Coupled to Micro Mechanical Oscillators =

NASA Astrophysics Data System (ADS)

Montoya Monge, Cris A.

Micro mechanical oscillators can serve as probes in precision measurements, as transducers to mediate photon-phonon interactions, and when functionalized with magnetic material, as tools to manipulate spins in quantum systems. This dissertation includes two projects where the interactions between cold atoms and mechanical oscillators are studied. In one of the experiments, we have manipulated the Zeeman state of magnetically trapped Rubidium atoms with a magnetic micro cantilever. The results show a spatially localized effect produced by the cantilever that agrees with Landau-Zener theory. In the future, such a scalable system with highly localized interactions and the potential for single-spin sensitivity could be useful for applications in quantum information science or quantum simulation. In a second experiment, work is in progress to couple a sample of optically trapped Rubidium atoms to a levitated nanosphere via an optical lattice. This coupling enables the cooling of the center-of-mass motion of the nanosphere by laser cooling the atoms. In this system, the atoms are trapped in the optical lattice while the sphere is levitated in a separate vacuum chamber by a single-beam optical tweezer. Theoretical analysis of such a system has determined that cooling the center-of-mass motion of the sphere to its quantum ground state is possible, even when starting at room temperature, due to the excellent environmental decoupling achievable in this setup. Nanospheres cooled to the quantum regime can provide new tests of quantum behavior at mesoscopic scales and have novel applications in precision sensing.

Interstellar Lithium and Rubidium in the Diffuse Gas Near IC 443

NASA Astrophysics Data System (ADS)

Ritchey, Adam M.; Taylor, C. J.; Federman, S. R.; Lambert, D. L.

2011-01-01

We present an analysis of interstellar lithium and rubidium from observations made with the Hobby-Eberly Telescope at McDonald Observatory of the Li I λ6707 and Rb I λ7800 absorption lines along four lines of sight through the supernova remnant IC 443. The observations probe interstellar material polluted by the ejecta of a core-collapse (Type II) supernova and can thus be used to constrain the contribution from massive stars to the synthesis of lithium and rubidium. Production of 7Li is expected to occur through neutrino spallation in the helium and carbon shells of the progenitor star during the terminal supernova explosion, while both 6Li and 7Li are synthesized via spallation and fusion reactions involving cosmic rays accelerated by the remnant. Gamma-ray emission from IC 443 provides strong evidence for the interaction of accelerated cosmic rays with the ambient atomic and molecular gas. Rubidium is also produced by massive stars through the weak s-process in the He- and C-burning shells and the r-process during core collapse. We examine interstellar 7Li/6Li isotope ratios as well as Li/K and Rb/K ratios along each line of sight, and discuss the implications of our results in the context of nucleosynthesis associated with Type II supernovae.

Coherent optical transients observed in rubidium atomic line filtered Doppler velocimetry experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fajardo, Mario E., E-mail: mario.fajardo@eglin.af.mil; Molek, Christopher D.; Vesely, Annamaria L.

2015-10-14

We report the first successful results from our novel Rubidium Atomic Line Filtered (RALF) Doppler velocimetry apparatus, along with unanticipated oscillatory signals due to coherent optical transients generated within pure Rb vapor cells. RALF is a high-velocity and high-acceleration extension of the well-known Doppler Global Velocimetry (DGV) technique for constructing multi-dimensional flow velocity vector maps in aerodynamics experiments [H. Komine, U.S. Patent No. 4,919,536 (24 April 1990)]. RALF exploits the frequency dependence of pressure-broadened Rb atom optical absorptions in a heated Rb/N{sub 2} gas cell to encode the Doppler shift of reflected near-resonant (λ{sub 0} ≈ 780.24 nm) laser light onto the intensitymore » transmitted by the cell. The present RALF apparatus combines fiber optic and free-space components and was built to determine suitable operating conditions and performance parameters for the Rb/N{sub 2} gas cells. It yields single-spot velocities of thin laser-driven-flyer test surfaces and incorporates a simultaneous Photonic Doppler Velocimetry (PDV) channel [Strand et al., Rev. Sci. Instrum. 77, 083108 (2006)] for validation of the RALF results, which we demonstrate here over the v = 0 to 1 km/s range. Both RALF and DGV presume the vapor cells to be simple Beer's Law optical absorbers, so we were quite surprised to observe oscillatory signals in experiments employing low pressure pure Rb vapor cells. We interpret these oscillations as interference between the Doppler shifted reflected light and the Free Induction Decay (FID) coherent optical transient produced within the pure Rb cells at the original laser frequency; this is confirmed by direct comparison of the PDV and FID signals. We attribute the different behaviors of the Rb/N{sub 2} vs. Rb gas cells to efficient dephasing of the atomic/optical coherences by Rb-N{sub 2} collisions. The minimum necessary N{sub 2} buffer gas density ≈0.3 amagat translates into a smallest useful velocity range of 0 to 2 km/s, which can readily be extended to cover the 0 to 10 km/s range, and beyond. The recognition that coherent optical transients can be produced within low pressure vapor cells during velocimetry experiments may offer new insights into some quantitative discrepancies reported in earlier DGV studies. Future plans include “line-RALF” experiments with streak camera detection, and two-dimensional surface velocity mapping using pulsed laser illumination and/or gated intensified CCD camera detection.« less

Metrological features of the rubidium two-photon standards of the BNM-LPTF and Kastler Brossel Laboratories

NASA Astrophysics Data System (ADS)

Hilico, L.; Felder, R.; Touahri, D.; Acef, O.; Clairon, A.; Biraben, F.

1998-11-01

We have built three optical frequency standards based on the two-photon transition of rubidium at 778nm, and analysed their performance over a period of more than three years. We discuss some systematic effects that could lead to the reproducibility we observe, and point out the possible improvements of the devices. We also examine the short and long term stabilities of the systems, and show that we have reached their ultimate performances.

Matterwave interferometric velocimetry of cold Rb atoms

NASA Astrophysics Data System (ADS)

Carey, Max; Belal, Mohammad; Himsworth, Matthew; Bateman, James; Freegarde, Tim

2018-03-01

We consider the matterwave interferometric measurement of atomic velocities, which forms a building block for all matterwave inertial measurements. A theoretical analysis, addressing both the laboratory and atomic frames and accounting for residual Doppler sensitivity in the beamsplitter and recombiner pulses, is followed by an experimental demonstration, with measurements of the velocity distribution within a 20 ?K cloud of rubidium atoms. Our experiments use Raman transitions between the long-lived ground hyperfine states, and allow quadrature measurements that yield the full complex interferometer signal and hence discriminate between positive and negative velocities. The technique is most suitable for measurement of colder samples.

Matterwave interferometric velocimetry of cold Rb atoms

NASA Astrophysics Data System (ADS)

Carey, Max; Belal, Mohammad; Himsworth, Matthew; Bateman, James; Freegarde, Tim

2018-02-01

We consider the matterwave interferometric measurement of atomic velocities, which forms a building block for all matterwave inertial measurements. A theoretical analysis, addressing both the laboratory and atomic frames and accounting for residual Doppler sensitivity in the beamsplitter and recombiner pulses, is followed by an experimental demonstration, with measurements of the velocity distribution within a 20 $\\mu$K cloud of rubidium atoms. Our experiments use Raman transitions between the long-lived ground hyperfine states, and allow quadrature measurements that yield the full complex interferometer signal and hence discriminate between positive and negative velocities. The technique is most suitable for measurement of colder samples.

Parallel Low-Loss Measurement of Multiple Atomic Qubits

NASA Astrophysics Data System (ADS)

Kwon, Minho; Ebert, Matthew F.; Walker, Thad G.; Saffman, M.

2017-11-01

We demonstrate low-loss measurement of the hyperfine ground state of rubidium atoms by state dependent fluorescence detection in a dipole trap array of five sites. The presence of atoms and their internal states are minimally altered by utilizing circularly polarized probe light and a strictly controlled quantization axis. We achieve mean state detection fidelity of 97% without correcting for imperfect state preparation or background losses, and 98.7% when corrected. After state detection and correction for background losses, the probability of atom loss due to the state measurement is <2 % and the initial hyperfine state is preserved with >98 % probability.

Performance of a GaAlAs laser diode stabilized on a hyperfine component of two-photon transitions in rubidium at 778 nm

NASA Astrophysics Data System (ADS)

Felder, Raymond; Touahri, D.; Acef, Ouali; Hilico, L.; Zondy, Jean-Jacques; Clairon, Andre; de Beauvoir, Beatrice; Biraben, Francois; Julien, Lucile; Nez, Francois; Millerioux, Yves P.

1995-04-01

The absolute frequency measurement of each hyperfine component of the 5S3/2 and 5S5/2 levels in rubidium was done at ENS more than one year ago using Ti-Sa lasers. We built two devices based on diode lasers to study some metrological properties. We measure the frequency differences between hyperfine components of the 5S5/2 level and we calculate the corresponding hyperfine constants. We also measure the frequency interval between the 5S3/2 and 5S5/2 levels using a Schottky diode. The measured stability in terms of Allan variance is 3*10-13t-1/2 up to 2000 s. The light shift is investigated and the difference between our two systems is 1.7 kHz. The repeatability of one system is better than 10-12 and will allow the absolute frequency measurement at this level via the LPTF frequency synthesis chain.

11 W narrow linewidth laser source at 780nm for laser cooling and manipulation of Rubidium

NASA Astrophysics Data System (ADS)

Sané, S. S.; Bennetts, S.; Debs, J. E.; Kuhn, C. C. N.; McDonald, G. D.; Altin, P. A.; Close, J. D.; Robins, N. P.

2012-04-01

We present a narrow linewidth continuous laser source with over 11 Watts of output power at 780nm, based on single-pass frequency doubling of an amplified 1560nm fibre laser with 36% efficiency. This source offers a combination of high power, simplicity, mode quality and stability. Without any active stabilization, the linewidth is measured to be below 10kHz. The fibre seed is tunable over 60GHz, which allows access to the D2 transitions in 87Rb and 85Rb, providing a viable high-power source for laser cooling as well as for large-momentum-transfer beamsplitters in atom interferometry. Sources of this type will pave the way for a new generation of high flux, high duty-cycle degenerate quantum gas experiments.

Lamp reliability studies for improved satellite rubidium frequency standard

NASA Technical Reports Server (NTRS)

Frueholz, R. P.; Wun-Fogle, M.; Eckert, H. U.; Volk, C. H.; Jones, P. F.

1982-01-01

In response to the premature failure of Rb lamps used in Rb atomic clocks onboard NAVSTAR GPS satellites experimental and theoretical investigations into their failure mechanism were initiated. The primary goal of these studies is the development of an accelerated life test for future GPS lamps. The primary failure mechanism was identified as consumption of the lamp's Rb charge via direct interaction between Rb and the lamp's glass surface. The most effective parameters to accelerate the interaction between the Rb and the glass are felt to be RF excitation power and lamp temperature. Differential scanning calorimetry is used to monitor the consumption of Rb within a lamp as a function of operation time. This technique yielded base line Rb consumption data for GPS lamps operating under normal conditions.

Classification of commercial wines from the Canary Islands (Spain) by chemometric techniques using metallic contents.

PubMed

Frías, Sergio; Conde, José E; Rodríguez-Bencomo, Juan J; García-Montelongo, Francisco; Pérez-Trujillo, Juan P

2003-02-06

Eleven elements, K, Na, Ca, Mg, Fe, Cu, Zn, Mn, Sr, Li and Rb, were determined in dry and sweet wines bearing the denominations of origin of El Hierro, La Palma and Lanzarote islands (Canary Islands, Spain). Analyses were performed by flame atomic absorption spectrophotometry, with the exceptions of lithium and rubidium for which flame atomic emission spectrophotometry was used. Sweet wines from La Palma were elaborated as naturally sweet with over-ripe grapes and significant differences were found in all the analysed elements with the exceptions of sodium, iron and rubidium with regard to dry wines from the same island. Contrarily, sweet wines from Lanzarote elaborated with grapes in a similar ripening state to dry wines did not present significant differences between them with the exception of strontium, the content of which was greater in dry wines. Among the three islands, significant differences in mean content were found with the exceptions of iron and copper. Cluster analysis and principal component analysis show differences in wines according to the island of origin and the ripening state of the grapes. Linear discriminant analysis using rubidium, sodium, manganese and strontium, the four most discriminant elements, gave 100% recognition ability and 95.6% prediction ability. The sensitivity and specificity obtained using soft independent modelling of class analogy (SIMCA) as a modelling multivariate technique were both 100% for El Hierro and Lanzarote, and 100 and 95%, respectively, for La Palma. The modelling and discriminant capacities of the different metals were also studied.

An auto-locked diode laser system for precision metrology

NASA Astrophysics Data System (ADS)

Beica, H. C.; Carew, A.; Vorozcovs, A.; Dowling, P.; Pouliot, A.; Barron, B.; Kumarakrishnan, A.

2017-05-01

We present a unique external cavity diode laser system that can be auto-locked with reference to atomic and molecular spectra. The vacuum-sealed laser head design uses an interchangeable base-plate comprised of a laser diode and optical elements that can be selected for desired wavelength ranges. The feedback light to the laser diode is provided by a narrow-band interference filter, which can be tuned from outside the laser cavity to fineadjust the output wavelength in vacuum. To stabilize the laser frequency, the digital laser controller relies either on a pattern-matching algorithm stored in memory, or on first or third derivative feedback. We have used the laser systems to perform spectroscopic studies in rubidium at 780 nm, and in iodine at 633 nm. The linewidth of the 780-nm laser system was measured to be ˜500 kHz, and we present Allan deviation measurements of the beat note and the lock stability. Furthermore, we show that the laser system can be the basis for a new class of lidar transmitters in which a temperature-stabilized fiber-Bragg grating is used to generate frequency references for on-line points of the transmitter. We show that the fiber-Bragg grating spectra can be calibrated with reference to atomic transitions.

A look into the crystal ball: The next 25 years

NASA Technical Reports Server (NTRS)

Hellwig, Helmut

1994-01-01

The PTTI Planning Meeting was born at about the same time as the atomic definition of the unit of time, the second. This use of the cesium resonance was made possible by advances in quantum electronics during the preceding decade which resulted in commercial availability of cesium, rubidium, and hydrogen clocks and frequency standards. Twenty-five years later these types of clocks still are the backbone of time and frequency applications; together with a variety of crystal oscillators, transmitters, and receivers, as well as signal distribution, conditioning and switching systems, atomic clocks are an essential part of the infrastructure of modern navigation and communication technology. The next 25 years undoubtedly will see a pervasive expansion of PTTI into the infrastructure that supports and leverages industrial, social, environmental, defense, and even individual human activities. Speculation as to what capabilities, services, and personal conveniences may become available will be limited by two factors: the degree to which existing device concepts can be made more affordable and reliable, and the ability to miniaturize for purposes of compatibility with electronic integration. With regard to the latter, history teaches us that the required technological breakthrough is unlikely to originate in existing technology; thus, we may expect a paradigm shift in PTTI device concepts not unlike the shift in the 1960s from vacuum tubes to semiconductors.

Monte Carlo simulations of precise timekeeping in the Milstar communication satellite system

NASA Technical Reports Server (NTRS)

Camparo, James C.; Frueholz, R. P.

1995-01-01

The Milstar communications satellite system will provide secure antijam communication capabilities for DOD operations into the next century. In order to accomplish this task, the Milstar system will employ precise timekeeping on its satellites and at its ground control stations. The constellation will consist of four satellites in geosynchronous orbit, each carrying a set of four rubidium (Rb) atomic clocks. Several times a day, during normal operation, the Mission Control Element (MCE) will collect timing information from the constellation, and after several days use this information to update the time and frequency of the satellite clocks. The MCE will maintain precise time with a cesium (Cs) atomic clock, synchronized to UTC(USNO) via a GPS receiver. We have developed a Monte Carlo simulation of Milstar's space segment timekeeping. The simulation includes the effects of: uplink/downlink time transfer noise; satellite crosslink time transfer noise; satellite diurnal temperature variations; satellite and ground station atomic clock noise; and also quantization limits regarding satellite time and frequency corrections. The Monte Carlo simulation capability has proven to be an invaluable tool in assessing the performance characteristics of various timekeeping algorithms proposed for Milstar, and also in highlighting the timekeeping capabilities of the system. Here, we provide a brief overview of the basic Milstar timekeeping architecture as it is presently envisioned. We then describe the Monte Carlo simulation of space segment timekeeping, and provide examples of the simulation's efficacy in resolving timekeeping issues.

Joint CPT and N resonance in compact atomic time standards

NASA Astrophysics Data System (ADS)

Crescimanno, Michael; Hohensee, Michael; Xiao, Yanhong; Phillips, David; Walsworth, Ron

2008-05-01

Currently development efforts towards small, low power atomic time standards use current-modulated VCSELs to generate phase-coherent optical sidebands that interrogate the hyperfine structure of alkali atoms such as rubidium. We describe and use a modified four-level quantum optics model to study the optimal operating regime of the joint CPT- and N-resonance clock. Resonant and non-resonant light shifts as well as modulation comb detuning effects play a key role in determining the optimal operating point of such clocks. We further show that our model is in good agreement with experimental tests performed using Rb-87 vapor cells.

Quantum delayed-choice experiment with a single neutral atom.

PubMed

Li, Gang; Zhang, Pengfei; Zhang, Tiancai

2017-10-01

We present a proposal to implement a quantum delayed-choice (QDC) experiment with a single neutral atom, such as a rubidium or cesium atom. In our proposal, a Ramsey interferometer is adopted to observe the wave-like or particle-like behaviors of a single atom depending on the existence or absence of the second π/2-rotation. A quantum-controlled π/2-rotation on target atom is realized through a Rydberg-Rydberg interaction by another ancilla atom. It shows that a heavy neutral atom can also have a morphing behavior between the particle and the wave. The realization of the QDC experiment with such heavy neutral atoms not only is significant to understand the Bohr's complementarity principle in matter-wave and matter-particle domains but also has great potential on the quantum information process with neutral atoms.

Engineering Photon-Photon Interactions within Rubidium-Filled Waveguides

NASA Astrophysics Data System (ADS)

Perrella, C.; Light, P. S.; Vahid, S. Afshar; Benabid, F.; Luiten, A. N.

2018-04-01

Strong photon-photon interactions are a required ingredient for deterministic two-photon optical quantum logic gates. Multiphoton transitions in dense atomic vapors have been shown to be a promising avenue for producing such interactions. The strength of a multiphoton interaction can be enhanced by conducting the interaction in highly confined geometries such as small-cross-section optical waveguides. We demonstrate, both experimentally and theoretically, that the strength of such interactions scale only with the optical mode diameter, d , not d2 as might be initially expected. This weakening of the interaction arises from atomic motion inside the waveguides. We create an interaction between two optical signals, at 780 and 776 nm, using the 5 S1 /2→5 D5 /2 two-photon transition in rubidium vapor within a range of hollow-core fibers with different core sizes. The interaction strength is characterized by observing the absorption and phase shift induced on the 780-nm beam, which is in close agreement with theoretical modeling that accounts for the atomic motion inside the fibers. These observations demonstrate that transit-time effects upon multiphoton transitions are of key importance when engineering photon-photon interactions within small-cross-section waveguides that might otherwise be thought to lead to enhanced optical nonlinearity through increased intensities.

Time and frequency technology at NIST

NASA Technical Reports Server (NTRS)

Sullivan, D. B.

1994-01-01

The state of development of advanced timing systems at NIST is described. The work on cesium and rubidium frequency standards, stored-ion frequency standards, diode lasers used to pump such standards, time transfer, and methods for characterizing clocks, oscillators, and time distribution systems is presented. The emphasis is on NIST-developed technology rather than the general state of the art in this field.

Frequency stability of on-orbit GPS Block-I and Block-II Navstar clocks

NASA Astrophysics Data System (ADS)

McCaskill, Thomas B.; Reid, Wilson G.; Buisson, James A.

On-orbit analysis of the Global Positioning System (GPS) Block-I and Block-II Navstar clocks has been performed by the Naval Research Laboratory using a multi-year database. The Navstar clock phase-offset measurements were computed from pseudorange measurements made by the five GPS monitor sites and from the U.S. Naval Observatory precise-time site using single or dual frequency GPS receivers. Orbital data was obtained from the Navstar broadcast ephemeris and from the best-fit, postprocessed orbital ephemerides supplied by the Naval Surface Weapons Center or by the Defense Mapping Agency. Clock performance in the time domain is characterized using frequency-stability profiles with sample times that vary from 1 to 100 days. Composite plots of Navstar frequency stability and time-prediction uncertainty are included as a summary of clock analysis results. The analysis includes plots of the clock phase offset and frequency offset histories with the eclipse seasons superimposed on selected plots to demonstrate the temperature sensitivity of one of the Block-I Navstar rubidium clocks. The potential impact on navigation and on transferring precise time of the degradation in the long-term frequency stability of the rubidium clocks is discussed.

An atomic beam source for fast loading of a magneto-optical trap under high vacuum

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDowall, Peter D.; Gruenzweig, Tzahi; Hilliard, Andrew

2012-05-15

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 is capable of loading 90% of a magneto-optical trap (MOT) in less than 7 s while maintaining a low vacuum pressure of <10{sup -11} Torr. The transverse velocity components of the atomic beam are measured to be within typical capture velocities of a rubidium MOT. Finally, we showmore » that the atomic beam can be turned off within 1.8 s.« less

Simultaneous trapping of rubidium-85 and rubidium-87 in a far off resonant trap

NASA Astrophysics Data System (ADS)

Gorges, Anthony R.

The experiments described in this thesis were focused on the physics of simultaneous trapping of 85Rb and 87 Rb into a Far Off Resonant Trap (FORT), with a view towards the implementation of a nonevaporative cooling scheme. Atoms were first trapped in a Magneto Optical Trap (MOT) and from there loaded into the FORT. We investigated the effects of loading the FORT from a MOT vs. an optical molasses; observing that the molasses significantly improved the trapped atom number. The ultimate number of atoms trapped is determined by a balance between efficient laser cooling into the FORT and light-assisted collisional losses from the FORT. We have studied and measured the loss rates associated with light-assisted collisions for our FORT, measuring both heteronuclear and homonuclear collisions. It was discovered that induced long range dipole-dipole interactions between 85Rb and 87Rb have a significant impact on FORT loading. This interaction interferes with the loading into the trap and thus limits the number of atoms which can be trapped in the FORT under simultaneous load conditions. Despite this limitation, all required experimental parameters for our future measurements have been met. In addition to these FORT studies, we have found a technique which can successfully mitigate the effects of reabsorption in optically thick clouds, which is a limitation to the ultimate temperature an atom cloud will reach during light-based cooling. Planned future measurements for this project include the creation of a variable aspect ratio FORT; along with investigating collision assisted Zeeman cooling.

Design of a Permanent-Magnet Zeeman Slower

NASA Astrophysics Data System (ADS)

Adler, Charles; Narducci, Frank; Sukenik, Charles; Mulholland, Jonathan; Goodale, Sarah

2006-05-01

During the past decade, low cost, flexible, and highly-polarized magnetic field sheet material has become available with field strengths useful for applications in modern atomic physics experiments. One advantage of using such material is that it can easily be cut to almost any desired shape without appreciable loss of field strength making it more versatile than ceramic magnets. We present the design of a Zeeman slower, made from such material, for cooling an atomic beam of neutral rubidium atoms and discuss results from an atomic beam trajectory simulation which indicates that the slower should perform well. We will also report on progress of a prototype permanent magnet Zeeman slower presently under construction in the laboratory.

A minimalistic and optimized conveyor belt for neutral atoms.

PubMed

Roy, Ritayan; Condylis, Paul C; Prakash, Vindhiya; Sahagun, Daniel; Hessmo, Björn

2017-10-20

Here we report of a design and the performance of an optimized micro-fabricated conveyor belt for precise and adiabatic transportation of cold atoms. A theoretical model is presented to determine optimal currents in conductors used for the transportation. We experimentally demonstrate a fast adiabatic transportation of Rubidium ( 87 Rb) cold atoms with minimal loss and heating with as few as three conveyor belt conductors. This novel design of a multilayered conveyor belt structure is fabricated in aluminium nitride (AlN) because of its outstanding thermal and electrical properties. This demonstration would pave a way for a compact and portable quantum device required for quantum information processing and sensors, where precise positioning of cold atoms is desirable.

Techniques for measuring the atomic recoil frequency using a grating-echo atom interferometer

NASA Astrophysics Data System (ADS)

Barrett, Brynle

I have developed three types of time-domain echo atom interferometer (AIs) that use either two or three standing-wave pulses in different configurations. Experiments approaching the transit time limit are achieved using samples of laser-cooled rubidium atoms with temperatures < 5 μK contained within a glass vacuum chamber—an environment that is largely free of both magnetic fields and field gradients. The principles of the atom-interferometric measurement of Eq can be understood based on a description of the "two-pulse" AI. This interferometer uses two standing-wave pulses applied at times t = 0 and t = T 21 to create a superposition of atomic momentum states differing by multiples of the two-photon momentum, ħq = 2 ħk where k is the optical wave number, that interfere in the vicinity of t = 2T 21. This interference or "echo" manifests itself as a density grating in the atomic sample, and is probed by applying a near-resonant traveling-wave "read-out" pulse and measuring the intensity of the coherent light Bragg-scattered in the backward direction. The scattered light from the grating is associated with a λ/2-periodic modulation produced by the interference of momentum states differing by ħq. Interfering states that differ by more than ħq—which produce higher-frequency spatial modulation within the sample—cannot be detected due to the nature of the Bragg scattering detection technique employed in the experiment. The intensity of the scattered light varies in a periodic manner as a function of the standing-wave pulse separation, T21. The fundamental frequency of this modulation is the two-photon atomic recoil frequency, ω q = ħq2/2M, where q = 2k and M is the mass of the atom (a rubidium isotope in this case). The recoil frequency, ω q, is related to the recoil energy, Eq = ħωq, which is the kinetic energy associated with the recoil of the atom after a coherent two-photon scattering process. By performing the experiment on a suitably long time scale ( T21 >> τq = π/ω q ˜32 μs), ωq can be measured precisely. Since ωq contains the ratio of Planck's constant to the mass of the atom, h/M, a precise measurement of ωq can be used as a strict test of quantum theories of the electromagnetic force. This two-pulse technique has a number of disadvantages for a precision measurement of ωq, such as a complicated functional dependence on T21 (due to the nature of Kapitza-Dirac diffraction, the level structure of the atom, and spontaneous emission). However, many of these difficulties can be avoided by using a three-pulse "perturbative" echo technique, where a third standing-wave pulse is applied at t = T21 + δT , with δT < T21. The function of the third pulse is to convert the difference between interfering momentum states from nħq (n > 1) to ħq. In this manner, interference between high-order momentum states contributes more significantly to the three-pulse echo than to the two-pulse echo. By fixing T21 and varying δT between the second standing-wave pulse and the echo time, the signal exhibits a simple shape with narrow fringes that revive periodically at the recoil period, τq. Using this technique, I have achieved a single measurement of ωq with a relative statistical uncertainty of ˜ 180 parts per 109 (ppb) on a time scale of 2T21 ˜ 72 ms in ˜ 15 minutes of data acquisition. Further improvements are anticipated by extending the experimental time scale and narrowing the signal fringe width. To demonstrate the final statistical uncertainty using the current configuration of the experiment, I acquired 82 individual measurements of ω q under the same experimental conditions. This resulted in a final measurement with a statistical precision of 37 ppb. However, this measurement is currently overwhelmed by systematic errors at the level of ˜ 5.7 parts per 106 (ppm). The first survey of systematic effects on the measurement of ωq with this technique has also been carried out, where individual measurements had relative statistical uncertainties of ≲ 1 ppm. These experimental studies, along with theoretical calculations, can be used to reduce and eliminate such effects in future rounds of experimentation. (Abstract shortened by UMI.).

Light-induced atomic desorption in a compact system for ultracold atoms

PubMed Central

Torralbo-Campo, Lara; Bruce, Graham D.; Smirne, Giuseppe; Cassettari, Donatella

2015-01-01

In recent years, light-induced atomic desorption (LIAD) of alkali atoms from the inner surface of a vacuum chamber has been employed in cold atom experiments for the purpose of modulating the alkali background vapour. This is beneficial because larger trapped atom samples can be loaded from vapour at higher pressure, after which the pressure is reduced to increase the lifetime of the sample. We present an analysis, based on the case of rubidium atoms adsorbed on pyrex, of various aspects of LIAD that are useful for this application. Firstly, we study the intensity dependence of LIAD by fitting the experimental data with a rate-equation model, from which we extract a correct prediction for the increase in trapped atom number. Following this, we quantify a figure of merit for the utility of LIAD in cold atom experiments and we show how it can be optimised for realistic experimental parameters. PMID:26458325

Raman-Ramsey multizone spectroscopy in a pure rubidium vapor cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Failache, H.; Lenci, L.; Lezama, A.

2010-02-15

In view of application to a miniaturized spectroscopy system, we consider an optical setup that splits a laser beam into several parallel narrow light sheets allowing an effective beam expansion and consequently longer atom-light interaction times. We analyze the multizone coherent population trapping (MZCPT) spectroscopy of alkali-metal-vapor atoms, without buffer gas, in the presence of a split light beam. We show that the MZCPT signal is largely insensitive to intensity broadening. Experimentally observed spectra are in qualitative agreement with the predictions of a simplified model that describes each spectrum as an integral over the atomic velocity distribution of Ramsey multizonemore » spectra.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dalvit, Diego; Messina, Riccardo; Maia Neto, Paulo

We develop the scattering approach for the dispersive force on a ground state atom on top of a corrugated surface. We present explicit results to first order in the corrugation amplitude. A variety of analytical results are derived in different limiting cases, including the van der Waals and Casimir-Polder regimes. We compute numerically the exact first-order dispersive potential for arbitrary separation distances and corrugation wavelengths, for a Rubidium atom on top of a silicon or gold corrugated surface. We consider in detail the correction to the proximity force approximation, and present a very simple approximation algorithm for computing the potential.

Effect of atomic noise on optical squeezing via polarization self-rotation in a thermal vapor cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, M. T. L.; Hetet, G.; Peng, A.

2006-02-15

The traversal of an elliptically polarized optical field through a thermal vapor cell can give rise to a rotation of its polarization axis. This process, known as polarization self-rotation (PSR), has been suggested as a mechanism for producing squeezed light at atomic transition wavelengths. We show results of the characterization of PSR in isotopically enhanced rubidium-87 cells, performed in two independent laboratories. We observed that, contrary to earlier work, the presence of atomic noise in the thermal vapor overwhelms the observation of squeezing. We present a theory that contains atomic noise terms and show that a null result in squeezingmore » is consistent with this theory.« less

Sympathetic cooling of nanospheres with cold atoms

NASA Astrophysics Data System (ADS)

Montoya, Cris; Witherspoon, Apryl; Ranjit, Gambhir; Casey, Kirsten; Kitching, John; Geraci, Andrew

2016-05-01

Ground state cooling of mesoscopic mechanical structures could enable new hybrid quantum systems where mechanical oscillators act as transducers. Such systems could provide coupling between photons, spins and charges via phonons. It has recently been shown theoretically that optically trapped dielectric nanospheres could reach the ground state via sympathetic cooling with trapped cold atoms. This technique can be beneficial in cases where cryogenic operation of the oscillator is not practical. We describe experimental advances towards coupling an optically levitated dielectric nanosphere to a gas of cold Rubidium atoms. The sphere and the cold atoms are in separate vacuum chambers and are coupled using a one-dimensional optical lattice. This work is partially supported by NSF, Grant Nos. PHY-1205994,PHY-1506431.

Theoretical analyses of an injection-locked diode-pumped rubidium vapor laser.

PubMed

Cai, He; Gao, Chunqing; Liu, Xiaoxu; Wang, Shunyan; Yu, Hang; Rong, Kepeng; An, Guofei; Han, Juhong; Zhang, Wei; Wang, Hongyuan; Wang, You

2018-04-02

Diode-pumped alkali lasers (DPALs) have drawn much attention since they were proposed in 2001. The narrow-linewidth DPAL can be potentially applied in the fields of coherent communication, laser radar, and atomic spectroscopy. In this study, we propose a novel protocol to narrow the width of one kind of DPAL, diode-pumped rubidium vapor laser (DPRVL), by use of an injection locking technique. A kinetic model is first set up for an injection-locked DPRVL with the end-pumped configuration. The laser tunable duration is also analyzed for a continuous wave (CW) injection-locked DPRVL system. Then, the influences of the pump power, power of a master laser, and reflectance of an output coupler on the output performance are theoretically analyzed. The study should be useful for design of a narrow-linewidth DPAL with the relatively high output.

High efficiency coherent optical memory with warm rubidium vapour

PubMed Central

Hosseini, M.; Sparkes, B.M.; Campbell, G.; Lam, P.K.; Buchler, B.C.

2011-01-01

By harnessing aspects of quantum mechanics, communication and information processing could be radically transformed. Promising forms of quantum information technology include optical quantum cryptographic systems and computing using photons for quantum logic operations. As with current information processing systems, some form of memory will be required. Quantum repeaters, which are required for long distance quantum key distribution, require quantum optical memory as do deterministic logic gates for optical quantum computing. Here, we present results from a coherent optical memory based on warm rubidium vapour and show 87% efficient recall of light pulses, the highest efficiency measured to date for any coherent optical memory suitable for quantum information applications. We also show storage and recall of up to 20 pulses from our system. These results show that simple warm atomic vapour systems have clear potential as a platform for quantum memory. PMID:21285952

High efficiency coherent optical memory with warm rubidium vapour.

PubMed

Hosseini, M; Sparkes, B M; Campbell, G; Lam, P K; Buchler, B C

2011-02-01

By harnessing aspects of quantum mechanics, communication and information processing could be radically transformed. Promising forms of quantum information technology include optical quantum cryptographic systems and computing using photons for quantum logic operations. As with current information processing systems, some form of memory will be required. Quantum repeaters, which are required for long distance quantum key distribution, require quantum optical memory as do deterministic logic gates for optical quantum computing. Here, we present results from a coherent optical memory based on warm rubidium vapour and show 87% efficient recall of light pulses, the highest efficiency measured to date for any coherent optical memory suitable for quantum information applications. We also show storage and recall of up to 20 pulses from our system. These results show that simple warm atomic vapour systems have clear potential as a platform for quantum memory.

Rubidium, sodium and ouabain interactions on the influx of rubidium in rat red blood cells

PubMed Central

Beaugé, L. A.; Ortíz, Olga

1970-01-01

1. The activation curve of rubidium influx by external rubidium in rat red cells showed an inflexion at a concentration around 0·2 mM. This inflexion point was displaced to the right by ouabain. 2. The removal of sodium from the external solution changed the characteristics of the activation curve of rubidium influx. At external rubidium below 0·5 mM the uptake increased whereas above that concentration there was marked reduction. Thus the sodium-free effect on rubidium uptake is dependent on the external rubidium concentration. 3. With 0·25 mM rubidium, the relationship between increase of rubidium influx and reduction of external sodium followed a more or less exponential function. All the increment was ouabain-sensitive. 4. With a rubidium concentration above 0·5 mM the reduction of the rubidium uptake, as sodium was removed, followed curves of complex shape. With 10 mM rubidium, when sodium was reduced from 5 mM to zero, there was an increase instead of a further reduction. These results suggest interactions of several effects. 5. The ouabain sensitivity of the rubidium influx in rat red cells is smaller than in other systems studied up to now. The dose—response curve was shifted to the right as the rubidium concentration increased and a plateau was obtained with rubidium only below 1 mM at 10-5 M ouabain. When plotted as a percentage of the maximal inhibition the points fell into the theoretical curve following a simple one reactant/one site reaction. 6. Ouabain inhibition seems to be a complex function of at least three variables: the concentration of the glycoside, the concentration of sodium and the concentration of rubidium. When sodium was absent, 10 μM rubidium was able to prevent, to a great extent, the inhibition produced by 10-5 and 10-4 M ouabain. PMID:5499809

In situ single-atom array synthesis using dynamic holographic optical tweezers

PubMed Central

Kim, Hyosub; Lee, Woojun; Lee, Han-gyeol; Jo, Hanlae; Song, Yunheung; Ahn, Jaewook

2016-01-01

Establishing a reliable method to form scalable neutral-atom platforms is an essential cornerstone for quantum computation, quantum simulation and quantum many-body physics. Here we demonstrate a real-time transport of single atoms using holographic microtraps controlled by a liquid-crystal spatial light modulator. For this, an analytical design approach to flicker-free microtrap movement is devised and cold rubidium atoms are simultaneously rearranged with 2N motional degrees of freedom, representing unprecedented space controllability. We also accomplish an in situ feedback control for single-atom rearrangements with the high success rate of 99% for up to 10 μm translation. We hope this proof-of-principle demonstration of high-fidelity atom-array preparations will be useful for deterministic loading of N single atoms, especially on arbitrary lattice locations, and also for real-time qubit shuttling in high-dimensional quantum computing architectures. PMID:27796372

Optical gain in an optically driven three-level ? system in atomic Rb vapor

NASA Astrophysics Data System (ADS)

Ballmann, C. W.; Yakovlev, V. V.

2018-06-01

In this work, we report experimentally achieved optical gain of a weak probe beam in a three-level ? system in a low density Rubidium vapor cell driven by a single pump beam. The maximum measured gain of the probe beam was about 0.12%. This work could lead to new approaches for enhancing molecular spectroscopy applications.

Poly[(μ5-3,5-dinitro­benzoato)rubidium

PubMed Central

Miao, Yanqing; Zhang, Xiaoqing; Liu, Chunye

2011-01-01

The asymmetric unit of the title compound, [Rb(C7H3N2O6)]n, comprises an Rb cation and a 3,5-dinitro­benzoate anion. The Rb cation is eight-coordinated by O atoms from five 3,5-dinitro­benzoate anions. On the other hand, each 3,5-dinitro­benzoate anion links five Rb cations with the carboxyl­ate groups as μ3-bridging. The metal atom is firstly linked by the carboxyl­ate groups into a chain along the c-axis direction, which is further linked by bonds between the Rb and nitro O atoms, giving a three-dimensional framework. PMID:21836829

Simple-to-Complex Transformation in Liquid Rubidium.

PubMed

Gorelli, Federico A; De Panfilis, Simone; Bryk, Taras; Ulivi, Lorenzo; Garbarino, Gaston; Parisiades, Paraskevas; Santoro, Mario

2018-05-18

We investigated the atomic structure of liquid Rb along an isothermal path at 573 K, up to 23 GPa, by X-ray diffraction measurements. By raising the pressure, we observed a liquid-liquid transformation from a simple metallic liquid to a complex one. The transition occurs at 7.5 ± 1 GPa which is slightly above the first maximum of the T-P melting line. This transformation is traced back to the density-induced hybridization of highest electronic orbitals leading to the accumulation of valence electrons between Rb atoms and to the formation of interstitial atomic shells, a behavior that Rb shares with Cs and is likely to be common to all alkali metals.

Evanescent Wave Atomic Mirror

NASA Astrophysics Data System (ADS)

Ghezali, S.; Taleb, A.

2008-09-01

A research project at the "Laboratoire d'électronique quantique" consists in a theoretical study of the reflection and diffraction phenomena via an atomic mirror. This poster presents the principle of an atomic mirror. Many groups in the world have constructed this type of atom optics experiments such as in Paris-Orsay-Villetaneuse (France), Stanford-Gaithersburg (USA), Munich-Heidelberg (Germany), etc. A laser beam goes into a prism with an incidence bigger than the critical incidence. It undergoes a total reflection on the plane face of the prism and then exits. The transmitted resulting wave out of the prism is evanescent and repulsive as the frequency detuning of the laser beam compared to the atomic transition δ = ωL-ω0 is positive. The cold atomic sample interacts with this evanescent wave and undergoes one or more elastic bounces by passing into backward points in its trajectory because the atoms' kinetic energy (of the order of the μeV) is less than the maximum of the dipolar potential barrier ℏΩ2/Δ where Ω is the Rabi frequency [1]. In fact, the atoms are cooled and captured in a magneto-optical trap placed at a distance of the order of the cm above the prism surface. The dipolar potential with which interact the slow atoms is obtained for a two level atom in a case of a dipolar electric transition (D2 Rubidium transition at a wavelength of 780nm delivered by a Titane-Saphir laser between a fundamental state Jf = l/2 and an excited state Je = 3/2). This potential is corrected by an attractive Van der Waals term which varies as 1/z3 in the Lennard-Jones approximation (typical atomic distance of the order of λ0/2π where λ0 is the laser wavelength) and in 1/z4 if the distance between the atom and its image in the dielectric is big in front of λ0/2π. This last case is obtained in a quantum electrodynamic calculation by taking into account an orthornormal base [2]. We'll examine the role of spontaneous emission for which the rate is inversely proportional to the detuning δ and is responsible of the non specular aspect of the atomic reflection (atomic diffusion). In the contrary, we note that the specularity of the reflection preserve the coherence of the atomic wave packet. The atoms will constitute a probe of the rugosity of the prism surface which can be imperfect or super-polished.

Atomic Clock Based on Opto-Electronic Oscillator

NASA Technical Reports Server (NTRS)

Maleki, Lute; Yu, Nan

2005-01-01

A proposed highly accurate clock or oscillator would be based on the concept of an opto-electronic oscillator (OEO) stabilized to an atomic transition. Opto-electronic oscillators, which have been described in a number of prior NASA Tech Briefs articles, generate signals at frequencies in the gigahertz range characterized by high spectral purity but not by longterm stability or accuracy. On the other hand, the signals generated by previously developed atomic clocks are characterized by long-term stability and accuracy but not by spectral purity. The proposed atomic clock would provide high spectral purity plus long-term stability and accuracy a combination of characteristics needed to realize advanced developments in communications and navigation. In addition, it should be possible to miniaturize the proposed atomic clock. When a laser beam is modulated by a microwave signal and applied to a photodetector, the electrical output of the photodetector includes a component at the microwave frequency. In atomic clocks of a type known as Raman clocks or coherent-population-trapping (CPT) clocks, microwave outputs are obtained from laser beams modulated, in each case, to create two sidebands that differ in frequency by the amount of a hyperfine transition in the ground state of atoms of an element in vapor form in a cell. The combination of these sidebands produces a transparency in the population of a higher electronic level that can be reached from either of the two ground-state hyperfine levels by absorption of a photon. The beam is transmitted through the vapor to a photodetector. The components of light scattered or transmitted by the atoms in the two hyperfine levels mix in the photodetector and thereby give rise to a signal at the hyperfine- transition frequency. The proposed atomic clock would include an OEO and a rubidium- or cesium- vapor cell operating in the CPT/Raman regime (see figure). In the OEO portion of this atomic clock, as in a typical prior OEO, a laser beam would pass through an electro-optical modulator, the modulated beam would be fed into a fiber-optic delay line, and the delayed beam would be fed to a photodetector. The electrical output of the photodetector would be detected, amplified, filtered, and fed back to the microwave input port of the modulator. The laser would be chosen to have the same wavelength as that of the pertinent ground-state/higher-state transition of the atoms in the vapor. The modulator/ filter combination would be designed to operate at the microwave frequency of the hyperfine transition. Part of the laser beam would be tapped from the fiberoptic loop of the OEO and introduced into the vapor cell. After passing through the cell, this portion of the beam would be detected differentially with a tapped portion of the fiber-optically-delayed beam. The electrical output of the photodetector would be amplified and filtered in a loop that would control a DC bias applied to the modulator. In this manner, the long-term stability and accuracy of the atomic transition would be transferred to the OEO.

Cavity electromagnetically induced transparency via spontaneously generated coherence

NASA Astrophysics Data System (ADS)

Tariq, Muhammad; Ziauddin, Bano, Tahira; Ahmad, Iftikhar; Lee, Ray-Kuang

2017-09-01

A four-level N-type atomic ensemble enclosed in a cavity is revisited to investigate the influence of spontaneous generated coherence (SGC) on transmission features of weak probe light field. A weak probe field is propagating through the cavity where each atom inside the cavity follows four-level N-type atom-field configuration of rubidium (?) atom. We use input-output theory and study the interaction of atomic ensemble and three cavity fields which are coupled to the same cavity mode. A SGC affects the transmission properties of weak probe light field due to which a transparency window (cavity EIT) appears. At resonance condition the transparency window increases with increasing the SGC in the system. We also studied the influence of the SGC on group delay and investigated magnitude enhancement of group delay for the maximum SGC in the system.

Spatial EPR entanglement in atomic vapor quantum memory

NASA Astrophysics Data System (ADS)

Parniak, Michal; Dabrowski, Michal; Wasilewski, Wojciech

Spatially-structured quantum states of light are staring to play a key role in modern quantum science with the rapid development of single-photon sensitive cameras. In particular, spatial degree of freedom holds a promise to enhance continous-variable quantum memories. Here we present the first demonstration of spatial entanglement between an atomic spin-wave and a photon measured with an I-sCMOS camera. The system is realized in a warm atomic vapor quantum memory based on rubidium atoms immersed in inert buffer gas. In the experiment we create and characterize a 12-dimensional entangled state exhibiting quantum correlations between a photon and an atomic ensemble in position and momentum bases. This state allows us to demonstrate the Einstein-Podolsky-Rosen paradox in its original version, with an unprecedented delay time of 6 μs between generation of entanglement and detection of the atomic state.

Mach-Zehnder atom interferometer inside an optical fiber

NASA Astrophysics Data System (ADS)

Xin, Mingjie; Leong, Wuiseng; Chen, Zilong; Lan, Shau-Yu

2017-04-01

Precision measurement with light-pulse grating atom interferometry in free space have been used in the study of fundamental physics and applications in inertial sensing. Recent development of photonic band-gap fibers allows light for traveling in hollow region while preserving its fundamental Gaussian mode. The fibers could provide a very promising platform to transfer cold atoms. Optically guided matter waves inside a hollow-core photonic band-gap fiber can mitigate diffraction limit problem and has the potential to bring research in the field of atomic sensing and precision measurement to the next level of compactness and accuracy. Here, we will show our experimental progress towards an atom interferometer in optical fibers. We designed an atom trapping scheme inside a hollow-core photonic band-gap fiber to create an optical guided matter waves system, and studied the coherence properties of Rubidium atoms in this optical guided system. We also demonstrate a Mach-Zehnder atom interferometer in the optical waveguide. This interferometer is promising for precision measurements and designs of mobile atomic sensors.

Atom chip apparatus for experiments with ultracold rubidium and potassium gases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ivory, M. K.; Ziltz, A. R.; Fancher, C. T.

2014-04-15

We present a dual chamber atom chip apparatus for generating ultracold {sup 87}Rb and {sup 39}K atomic gases. The apparatus produces quasi-pure Bose-Einstein condensates of 10{sup 4} {sup 87}Rb atoms in an atom chip trap that features a dimple and good optical access. We have also demonstrated production of ultracold {sup 39}K and subsequent loading into the chip trap. We describe the details of the dual chamber vacuum system, the cooling lasers, the magnetic trap, the multicoil magnetic transport system, the atom chip, and two optical dipole traps. Due in part to the use of light-induced atom desorption, the lasermore » cooling chamber features a sufficiently good vacuum to also support optical dipole trap-based experiments. The apparatus is well suited for studies of atom-surface forces, quantum pumping and transport experiments, atom interferometry, novel chip-based traps, and studies of one-dimensional many-body systems.« less

Experimental realization of real-time feedback-control of single-atom arrays

NASA Astrophysics Data System (ADS)

Kim, Hyosub; Lee, Woojun; Ahn, Jaewook

2016-05-01

Deterministic loading of neutral atoms on particular locations has remained a challenging problem. Here we show, in a proof-of-principle experimental demonstration, that such deterministic loading can be achieved by rearrangement of atoms. In the experiment, cold rubidium atom were trapped by optical tweezers, which are the hologram images made by a liquid-crystal spatial light modulator (LC-SLM). After the initial occupancy was identified, the hologram was actively controlled to rearrange the captured atoms on to unfilled sites. For this, we developed a new flicker-free hologram algorithm that enables holographic atom translation. Our demonstration show that up to N=9 atoms were simultaneously moved in the 2D plane with the movable degrees of freedom of 2N=18 and the fidelity of 99% for single-atom 5- μm translation. It is hoped that our in situ atom rearrangement becomes useful in scaling quantum computers. Samsung Science and Technology Foundation [SSTF-BA1301-12].

The Road to DLCZ Protocol in Rubidium Ensemble

NASA Astrophysics Data System (ADS)

Li, Chang; Pu, Yunfei; Jiang, Nan; Chang, Wei; Zhang, Sheng; CenterQuantum Information, InstituteInterdisciplinary Information Sciences, Tsinghua Univ Team

2017-04-01

Quantum communication is the powerful approach achieving a fully secure information transferal. The DLCZ protocol ensures that photon linearly decays with transferring distance increasing, which improves the success potential and shortens the time to build up an entangled channel. Apart from that, it provides an advanced idea that building up a quantum internet based on different nodes connected to different sites and themselves. In our laboratory, three sets of laser-cooled Rubidium 87 ensemble have been built. Two of them serve as the single photon emitter, which generate the entanglement between ensemble and photon. What's more, crossed AODs are equipped to multiplex and demultiplex optical circuit so that ensemble is divided into 2 hundred of 2D sub-memory cells. And the third ensemble is used as quantum telecommunication, which converts 780nm photon into telecom-wavelength one. And we have been building double-MOT system, which provides more atoms in ensemble and larger optical density.

State-to-state chemistry for three-body recombination in an ultracold rubidium gas.

PubMed

Wolf, Joschka; Deiß, Markus; Krükow, Artjom; Tiemann, Eberhard; Ruzic, Brandon P; Wang, Yujun; D'Incao, José P; Julienne, Paul S; Denschlag, Johannes Hecker

2017-11-17

Experimental investigation of chemical reactions with full quantum state resolution for all reactants and products has been a long-term challenge. Here we prepare an ultracold few-body quantum state of reactants and demonstrate state-to-state chemistry for the recombination of three spin-polarized ultracold rubidium (Rb) atoms to form a weakly bound Rb 2 molecule. The measured product distribution covers about 90% of the final products, and we are able to discriminate between product states with a level splitting as small as 20 megahertz multiplied by Planck's constant. Furthermore, we formulate propensity rules for the distribution of products, and we develop a theoretical model that predicts many of our experimental observations. The scheme can readily be adapted to other species and opens a door to detailed investigations of inelastic or reactive processes. Copyright © 2017, American Association for the Advancement of Science.

A high repetition deterministic single ion source

NASA Astrophysics Data System (ADS)

Sahin, C.; Geppert, P.; Müllers, A.; Ott, H.

2017-12-01

We report on a deterministic single ion source with high repetition rate and high fidelity. The source employs a magneto-optical trap, where ultracold rubidium atoms are photoionized. The electrons herald the creation of a corresponding ion, whose timing information is used to manipulate its trajectory in flight. We demonstrate an ion rate of up to 4× {10}4 {{{s}}}-1 and achieve a fidelity for single ion operation of 98%. The technique can be used for all atomic species, which can be laser-cooled, and opens up new applications in ion microscopy, ion implantation and surface spectroscopy.

Laser demonstration and performance characterization of optically pumped Alkali Laser systems

NASA Astrophysics Data System (ADS)

Sulham, Clifford V.

Diode Pumped Alkali Lasers (DPALs) offer a promising approach for high power lasers in military applications that will not suffer from the long logistical trails of chemical lasers or the thermal management issues of diode pumped solid state lasers. This research focuses on characterizing a DPAL-type system to gain a better understanding of using this type of laser as a directed energy weapon. A rubidium laser operating at 795 nm is optically pumped by a pulsed titanium sapphire laser to investigate the dynamics of DPALs at pump intensities between 1.3 and 45 kW/cm2. Linear scaling as high as 32 times threshold is observed, with no evidence of second order kinetics. Comparison of laser characteristics with a quasi-two level analytic model suggests performance near the ideal steady-state limit, disregarding the mode mis-match. Additionally, the peak power scales linearly as high as 1 kW, suggesting aperture scaling to a few cm2 is sufficient to achieve tactical level laser powers. The temporal dynamics of the 100 ns pump and rubidium laser pulses are presented, and the continually evolving laser efficiency provides insight into the bottlenecking of the rubidium atoms in the 2P3/2 state. Lastly, multiple excited states of rubidium and cesium were accessed through two photon absorption in the red, yielding a blue and an IR photon through amplified stimulated emission. Threshold is modest at 0.3 mJ/pulse, and slope efficiencies increase dramatically with alkali concentrations and peak at 0.4%, with considerable opportunity for improvement. This versatile system might find applications for IR countermeasures or underwater communications.

Superradiance in a Large and Dilute Cloud of Cold Atoms in the Linear-Optics Regime.

PubMed

Araújo, Michelle O; Krešić, Ivor; Kaiser, Robin; Guerin, William

2016-08-12

Superradiance has been extensively studied in the 1970s and 1980s in the regime of superfluorescence, where a large number of atoms are initially excited. Cooperative scattering in the linear-optics regime, or "single-photon superradiance," has been investigated much more recently, and superradiant decay has also been predicted, even for a spherical sample of large extent and low density, where the distance between atoms is much larger than the wavelength. Here, we demonstrate this effect experimentally by directly measuring the decay rate of the off-axis fluorescence of a large and dilute cloud of cold rubidium atoms after the sudden switch off of a low-intensity laser driving the atomic transition. We show that, at large detuning, the decay rate increases with the on-resonance optical depth. In contrast to forward scattering, the superradiant decay of off-axis fluorescence is suppressed near resonance due to attenuation and multiple-scattering effects.

Implementation of quantum logic gates via Stark-tuned Förster resonance in Rydberg atoms

NASA Astrophysics Data System (ADS)

Huang, Xi-Rong; Hu, Chang-Sheng; Shen, Li-Tuo; Yang, Zhen-Biao; Wu, Huai-Zhi

2018-02-01

We present a scheme for implementation of controlled-Z and controlled-NOT gates via rapid adiabatic passage and Stark-tuned Förster resonance. By sweeping the Förster resonance once without passing through it and adiabatically tuning the angle-dependent Rydberg-Rydberg interaction of the dipolar nature, the system can be effectively described by a two-level system with the adiabatic theorem. The single adiabatic passage leads to a gate fidelity as high as 0.999 and a greatly reduced gate operation time. We investigate the scheme by considering an actual atomic level configuration with rubidium atoms, where the fidelity of the controlled-Z gate is still higher than 0.99 under the influence of the Zeeman effect.

Provisional Peer-Reviewed Toxicity Values for Rubidium Compounds (Rubidium Chloride)

EPA Science Inventory

This is a PPRTV for Rubidium Compounds submitted to the Superfund Program.This assessment supports multiple isomers (see related links) and this page is about the chemical rubidium chloride, CASRN 7791-11-9.

Provisional Peer-Reviewed Toxicity Values for Rubidium Compounds (Rubidium Iodide)

EPA Science Inventory

This is a PPRTV for Rubidium Compounds submitted to the Superfund Program.This assessment supports multiple isomers (see related links) and this page is about the chemical rubidium iodide, CASRN 7790-29-6.

Provisional Peer-Reviewed Toxicity Values for Rubidium Compounds (Rubidium Hydroxide)

EPA Science Inventory

This is a PPRTV for Rubidium Compounds submitted to the Superfund Program.This assessment supports multiple isomers (see related links) and this page is about the chemical rubidium hydroxide, CASRN 1310-82-3.

Metallic content of wines from the Canary Islands (Spain). Application of artificial neural networks to the data analysis.

PubMed

Frías, Sergio; Conde, José E; Rodríguez, Miguel A; Dohnal, Vlasta; Pérez-Trujillo, Juan P

2002-10-01

Eleven elements, K, Na, Ca, Mg, Fe, Cu, Zn, Mn, Sr, Li and Rb, were determined in dry and sweet wines bearing the denominations of origin of El Hierro, La Palma and Lanzarote islands (Canary Islands, Spain). Analyses were performed by flame atomic absorption spectrophotometry, with the exceptions of Li and Rb for which flame atomic emission spectrophotometry was used. The content in copper and iron did not present risks of cases. All samples presented a copper and zinc content below the maximum amount recommended by the Office International de la Vigne et du Vin (OIV) for these elements. Significant differences in the metallic content were found among the different islands. Thus, Lanzarote presented the highest mean content in sodium and lithium and the lowest mean content in rubidium, and La Palma presented the highest mean content in strontium and rubidium. Sweet wines from La Palma, elaborated as naturally sweet with over-ripe grapes, presented mean contents significantly higher with regard to dry wines from the same island in the majority of the analysed elements. Cluster analysis and Kohonen self-organising maps showed differences in wines according to the island of origin and the ripening state of the grapes. Back-propagation artificial neural networks showed better prediction ability than stepwise linear discriminant analysis.

Heading error in an alignment-based magnetometer

NASA Astrophysics Data System (ADS)

Hovde, Chris; Patton, Brian; Versolato, Oscar; Corsini, Eric; Rochester, Simon; Budker, Dmitry

2011-06-01

A prototype magnetometer for anti-submarine warfare applications is being developed based on nonlinear magneto-optical rotation (NMOR) in atomic vapors. NMOR is an atomic spectroscopy technique that exploits coherences among magnetic sublevels of atoms such as cesium or rubidium to measure magnetic fields with high precision. NMOR uses stroboscopic optical pumping via frequency or amplitude modulation of a linearly polarized laser beam to create the alignment. An anti-relaxation coating on the walls of the atomic vapor cell can result in a long lifetime of 1 s or more for the coherence and enables precise measurement of the precession frequency. With proper feedback, the magnetometer can self-oscillate, resulting in accurate tracking and fast time response. The NMOR magnetic resonance spectrum of 87Rb has been measured as a function of heading in Earth's field. Optical pumping of alignment within the F=2 hyperfine manifold generates three resonances separated by the nonlinear Zeeman splitting. The spectra show a high degree of symmetry, consisting of a central peak and two side peaks of nearly equal intensity. As the heading changes, the ratio of the central peak to the average of the two side peaks changes. The amplitudes of the side peaks remain nearly equal. An analysis of the forced oscillation spectra indicates that, away from dead zones, heading error in self-oscillating mode should be less than 1 nT. A broader background is also observed in the spectra. While this background can be removed when fitting resonance spectra, understanding it will be important to achieving the small heading error in self-oscillating mode that is implied by the spectral measurements. Progress in miniaturizing the magnetometer is also reported. The new design is less than 10 cm across and includes fiber coupling of light to and from the magnetometer head. Initial tests show that the prototype has achieved a narrow spectral width and a strong polarization rotation signal.

Observation of the fluorescence spectrum for a driven cascade model system in atomic beam.

PubMed

Tian, Si-Cong; Wang, Chun-Liang; Tong, Cun-Zhu; Wang, Li-Jun; Wang, Hai-Hua; Yang, Xiu-Bin; Kang, Zhi-Hui; Gao, Jin-Yue

2012-10-08

We experimentally study the resonance fluorescence from an excited two-level atom when the atomic upper level is coupled by a nonresonant field to a higher-lying state in a rubidium atomic beam. The heights, widths and positions of the fluorescence peaks can be controlled by modifying the detuning of the auxiliary field. We explain the observed spectrum with the transition properties of the dressed states generated by the coupling of the two laser fields. We also attribute the line narrowing to the effects of Spontaneously Generated Coherence between the close-lying levels in the dressed state picture generated by the auxiliary field. And the corresponding spectrum can be viewed as the evidence of Spontaneously Generated Coherence. The experimental results agree well with calculations based on the density-matrix equations.

Digital communication with Rydberg atoms and amplitude-modulated microwave fields

NASA Astrophysics Data System (ADS)

Meyer, David H.; Cox, Kevin C.; Fatemi, Fredrik K.; Kunz, Paul D.

2018-05-01

Rydberg atoms, with one highly excited, nearly ionized electron, have extreme sensitivity to electric fields, including microwave fields ranging from 100 MHz to over 1 THz. Here, we show that room-temperature Rydberg atoms can be used as sensitive, high bandwidth, microwave communication antennas. We demonstrate near photon-shot-noise limited readout of data encoded in amplitude-modulated 17 GHz microwaves, using an electromagnetically induced-transparency (EIT) probing scheme. We measure a photon-shot-noise limited channel capacity of up to 8.2 Mbit s-1 and implement an 8-state phase-shift-keying digital communication protocol. The bandwidth of the EIT probing scheme is found to be limited by the available coupling laser power and the natural linewidth of the rubidium D2 transition. We discuss how atomic communication receivers offer several opportunities to surpass the capabilities of classical antennas.

Rubidium Frequency Standard Study.

DTIC Science & Technology

1983-10-01

small size, rapid warmup, and low power consumption along with frequency stability, repeatability, 1-2 . . *1 %0 now- L~tt~ ~nine~j ?odel ISu and low...the resonance and/or filter * cells at reduced temperatures with thermoelectric coolers on the basis that too much power was required and magnetic...range is dictated by thermal and steady-stp’te power considera- -_tions imposed by the performance requirements. The filter cell serves two pri- *mary

Light storage in a cold atomic ensemble with a high optical depth

NASA Astrophysics Data System (ADS)

Park, Kwang-Kyoon; Chough, Young-Tak; Kim, Yoon-Ho

2017-06-01

A quantum memory with a high storage efficiency and a long coherence time is an essential element in quantum information applications. Here, we report our recent development of an optical quantum memory with a rubidium-87 cold atom ensemble. By increasing the optical depth of the medium, we have achieved a storage efficiency of 65% and a coherence time of 51 μs for a weak laser pulse. The result of a numerical analysis based on the Maxwell-Bloch equations agrees well with the experimental results. Our result paves the way toward an efficient optical quantum memory and may find applications in photonic quantum information processing.

Design and industrial production of frequency standards in the USSR

NASA Technical Reports Server (NTRS)

Demidov, Nikolai A.; Uljanov, Adolph A.

1990-01-01

Some aspects of research development and production of quantum frequency standards, carried out in QUARTZ Research and Production Association (RPA), Gorky, U.S.S.R., were investigated for the last 25 to 30 years. During this period a number of rubidium and hydrogen frequency standards, based on the active maser, were developed and put into production. The first industrial model of a passive hydrogen maser was designed in the last years. Besides frequency standards for a wide application range, RPA QUARTZ investigates metrological frequency standards--cesium standards with cavity length 1.9 m and hydrogen masers with a flexible storage bulb.

Calculations with the quasirelativistic local-spin-density-functional theory for high-Z atoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Y.; Whitehead, M.A.

1988-10-01

The generalized-exchange local-spin-density-functional theory (LSD-GX) with relativistic corrections of the mass velocity and Darwin terms has been used to calculate statistical total energies for the neutral atoms, the positive ions, and the negative ions for high-Z elements. The effect of the correlation and relaxation correction on the statistical total energy is discussed. Comparing the calculated results for the ionization potentials and electron affinities for the atoms (atomic number Z from 37 to 56 and 72 to 80) with experiment, shows that for the atoms rubidium to barium both the LSD-GX and the quasirelativistic LSD-GX, with self-interaction correction, Gopinathan, Whitehead, andmore » Bogdanovic's Fermi-hole parameters (Phys. Rev. A 14, 1 (1976)), and Vosko, Wilk, and Nusair's correlation correction (Can. J. Phys. 58, 1200 (1980)), are very good methods for calculating ionization potentials and electron affinities. For the atoms hafnium to mercury the relativistic effect has to be considered.« less

Inelastic collisions of positrons with one-valence-electron targets

NASA Technical Reports Server (NTRS)

Abdel-Raouf, Mohamed Assad

1990-01-01

The total elastic and positronium formation cross sections of the inelastic collisions between positrons and various one-valence-electron atoms, (namely hydrogen, lithium, sodium, potassium and rubidium), and one-valence-electron ions, (namely hydrogen-like, lithium-like and alkaline-earth positive ions) are determined using an elaborate modified coupled-static approximation. Special attention is devoted to the behavior of the Ps cross sections at the energy regions lying above the Ps formation thresholds.

Electronic Devices with Rubidium Barrier Film and Process for Making Same

DTIC Science & Technology

1998-08-20

barrier film is comprised of a plurality of contiguous monolayers, while FIG. 7B shows another embodiment of the 20 invention where the barrier film is... plurality of contiguous monolayers in which different monolayers thereof are formed of different types of metal atoms. -10- FIG. 8 is a schematic...system directed toward the substrate 26. A diffusion barrier precursor compound effusion cell, for example a barium fluoride, strontium fluoride or the

Realization of two-dimensional spin-orbit coupling for Bose-Einstein condensates.

PubMed

Wu, Zhan; Zhang, Long; Sun, Wei; Xu, Xiao-Tian; Wang, Bao-Zong; Ji, Si-Cong; Deng, Youjin; Chen, Shuai; Liu, Xiong-Jun; Pan, Jian-Wei

2016-10-07

Cold atoms with laser-induced spin-orbit (SO) interactions provide a platform to explore quantum physics beyond natural conditions of solids. Here we propose and experimentally realize two-dimensional (2D) SO coupling and topological bands for a rubidium-87 degenerate gas through an optical Raman lattice, without phase-locking or fine-tuning of optical potentials. A controllable crossover between 2D and 1D SO couplings is studied, and the SO effects and nontrivial band topology are observed by measuring the atomic cloud distribution and spin texture in momentum space. Our realization of 2D SO coupling with advantages of small heating and topological stability opens a broad avenue in cold atoms to study exotic quantum phases, including topological superfluids. Copyright © 2016, American Association for the Advancement of Science.

Multiple coherent light scattering in ultracold rubidium

NASA Astrophysics Data System (ADS)

Kulatunga, P.; Sukenik, C. I.; Havey, M. D.; Kupriyanov, D. V.; Sokolov, I. M.

2001-11-01

We report investigation of multiple coherent light scattering from ^85Rb atoms confined in a magneto-optic trap. In a theoretical study of intensity enhancement of near-resonant backscattered light from cold ^85,87Rb atoms, we consider the dominant mode of double scattering only. Enhancement factors are calculated for all D1 and D2 hyperfine components and for both isotopes. In experimental studies, measurements are made of coherent backscattering of a low-intensity probe beam tuned near the F = 3 - F' = 4 transition in ^85Rb atoms. Polarization of backscattered light is determined by a backscattering polarimeter; the spatial distribution of light intensity is measured by a liquid-nitrogen cooled CCD camera set in the focal plane of the analyzing optics. The instrument has angular resolution of about 100 micro-radians, and a polarization analyzing power of roughly 1000. In this paper we describe the instrument details, including calibration procedures, and progress towards observation of atomic coherent backscattering.

Coherent backscattering of light by an inhomogeneous cloud of cold atoms

NASA Astrophysics Data System (ADS)

Labeyrie, Guillaume; Delande, Dominique; Müller, Cord A.; Miniatura, Christian; Kaiser, Robin

2003-03-01

When a quasiresonant laser beam illuminates an optically thick cloud of laser-cooled rubidium atoms, the average diffuse intensity reflected off the sample is enhanced in a narrow angular range around the direction of exact backscattering. This phenomenon is known as coherent backscattering (CBS). By detuning the laser from resonance, we are able to modify the light scattering mean-free path inside the sample and we record accordingly the variations of the CBS cone shape. We then compare the experimental data with theoretical calculations and Monte Carlo simulations including the effect of the light polarization and of the internal structure of the atoms. We confirm that the internal structure strongly affects the enhancement factor of the cone and we show that the unusual shape of the atomic medium—approximately a spherically-symmetric, Gaussian density profile—strongly affects the width and shape of the cone.

Multiple coherent light scattering in ultracold rubidium

NASA Astrophysics Data System (ADS)

Havey, M. D.; Sukenik, C. I.; Kulatunga, P.; Kupriyanov, D. V.; Sokolov, I. M.

2001-05-01

We report investigation of multiple coherent light scattering from ^85Rb atoms confined in a magneto-optic trap. In a theoretical study of intensity enhancement of near-resonant backscattered light from cold ^85,87Rb atoms, we consider the dominant mode of double scattering only. Enhancement factors are calculated for all D1 and D2 hyperfine components and for both isotopes. In experimental studies, measurements are made of coherent backscattering of a low-intensity probe beam tuned near the F = 3 - F' = 4 transition in ^85Rb atoms. Polarization of backscattered light is determined by a backscattering polarimeter; the spatial distribution of light intensity is measured by a liquid-nitrogen cooled CCD camera set in the focal plane of the analyzing optics. The instrument has angular resolution of about 100 micro-radians, and a polarization analyzing power of roughly 1000. In this paper we describe the instrument details, including calibration procedures, and progress towards observation of atomic coherent backscattering.

Veselago lensing with ultracold atoms in an optical lattice.

PubMed

Leder, Martin; Grossert, Christopher; Weitz, Martin

2014-01-01

Veselago pointed out that electromagnetic wave theory allows for materials with a negative index of refraction, in which most known optical phenomena would be reversed. A slab of such a material can focus light by negative refraction, an imaging technique strikingly different from conventional positive refractive index optics, where curved surfaces bend the rays to form an image of an object. Here we demonstrate Veselago lensing for matter waves, using ultracold atoms in an optical lattice. A relativistic, that is, photon-like, dispersion relation for rubidium atoms is realized with a bichromatic optical lattice potential. We rely on a Raman π-pulse technique to transfer atoms between two different branches of the dispersion relation, resulting in a focusing that is completely analogous to the effect described by Veselago for light waves. Future prospects of the demonstrated effects include novel sub-de Broglie wavelength imaging applications.

Optical coupling of cold atoms to a levitated nanosphere

NASA Astrophysics Data System (ADS)

Montoya, Cris; Witherspoon, Apryl; Fausett, Jacob; Lim, Jason; Kitching, John; Geraci, Andrew

2017-04-01

Cooling mechanical oscillators to their quantum ground state enables the study of quantum phenomena at macroscopic levels. In many cases, the temperature required to cool a mechanical mode to the ground state is below what current cryogenic systems can achieve. As an alternative to cooling via cryogenic systems, it has been shown theoretically that optically trapped nanospheres could reach the ground state by sympathetically cooling the spheres via cold atoms. Such cooled spheres can be used in quantum limited sensing and matter-wave interferometry, and could also enable new hybrid quantum systems where mechanical oscillators act as transducers. In our setup, optical fields are used to couple a sample of cold Rubidium atoms to a nanosphere. The sphere is optically levitated in a separate vacuum chamber, while the atoms are trapped in a 1-D optical lattice and cooled using optical molasses. This work is partially supported by NSF, Grant No. PHY-1506431.

Directed Field Ionization: A Genetic Algorithm for Evolving Electric Field Pulses

NASA Astrophysics Data System (ADS)

Kang, Xinyue; Rowley, Zoe A.; Carroll, Thomas J.; Noel, Michael W.

2017-04-01

When an ionizing electric field pulse is applied to a Rydberg atom, the electron's amplitude traverses many avoided crossings among the Stark levels as the field increases. The resulting superposition determines the shape of the time resolved field ionization spectrum at a detector. An engineered electric field pulse that sweeps back and forth through avoided crossings can control the phase evolution so as to determine the electron's path through the Stark map. In the region of n = 35 in rubidium there are hundreds of potential avoided crossings; this yields a large space of possible pulses. We use a genetic algorithm to search this space and evolve electric field pulses to direct the ionization of the Rydberg electron in rubidium. We present the algorithm along with a comparison of simulated and experimental results. This work was supported by the National Science Foundation under Grants No. 1607335 and No. 1607377 and used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation Grant Number OCI-1053575.

Solvothermal syntheses and characterization of three new silver(I)/copper(I)-thioarsenates based on As2+/As3+ ions

NASA Astrophysics Data System (ADS)

Yao, Hua-Gang; Tang, Cheng-Fei; An, Yong-Lin; Ou, Zi-Jian; Wu, Guo-Hao; Lan, Pei; Zheng, Yi-Long

2017-02-01

Three new silver(I)/copper(I)-thioarsenates KAgAsIIS2 (1), RbCu2AsIIIS3 (2) and RbCu4AsIIIS4 (3) have been solvothermally synthesized and structurally characterized. 1 exhibits a two-dimensional anionic network built up by As-As bond connecting the left- and right-handed helical [AgS2]4- chains, and represents the first examples of thioarsenates(II). The structure of 2 consists of two kinds of helical [Cu2S3]4- chains linked by the arsenic atoms to form double layers with rubidium ions between the layers. Compound 3 is built up of infinite [Cu2S2]2- chain and layered [Cu6As2S6] linked to form a three-dimensional anionic framework, [Cu4AsS4]-, and containing channels in which the rubidium cations reside. The optical properties of 1-3 have been investigated by UV-vis spectroscopy.

Recovery of strontium activity from a strontium-82/rubidium-82 generator

DOEpatents

Taylor, Wayne A.; Phillips, Dennis R.; Sosnowski, Kenneth M.

1999-10-12

Strontium-82 is recovered from spent strontium-82/rubidium-82 generators to provide a source of strontium-82 for additional strontium-82/rubidium-82 generators. The process involves stripping of the strontium-82 from used strontium-82/rubidium-82 generators followed by purification of the strontium-82 material to remove additional metal contaminants to desired levels.

Quantum memory for squeezed light.

PubMed

Appel, Jürgen; Figueroa, Eden; Korystov, Dmitry; Lobino, M; Lvovsky, A I

2008-03-07

We produce a 600-ns pulse of 1.86-dB squeezed vacuum at 795 nm in an optical parametric amplifier and store it in a rubidium vapor cell for 1 mus using electromagnetically induced transparency. The recovered pulse, analyzed using time-domain homodyne tomography, exhibits up to 0.21+/-0.04 dB of squeezing. We identify the factors leading to the degradation of squeezing and investigate the phase evolution of the atomic coherence during the storage interval.

Cold Rydberg Atoms Trapped in a CO2 Optical Lattice

DTIC Science & Technology

2012-09-03

13566-590, São Carlos - SP - Brazil AF OFFICE OF SCIENTIFIC RESEARCH/IO 875 N. RANDOLPH ST. ROOM 3112 ARLINGTON VA 22203 AFRL-OSR-VA-TR-2012-1153...collaboration with Prof. Shaffer from University of Oklahoma. We have also compared the results obtained in Brazil for Rubidium with the results...INSTITUTO DE FÍSICA DE SÃO CARLOS / USP Av. Trabalhador SãoCarlense 400, Cx. Postal 369 13566-560 São Carlos, SP, Brazil 2 Principal

Two-photon absorption dispersion spectrometer for 1.53 μm eye-safe Doppler LIDAR.

PubMed

Vance, J D

2012-07-01

Based upon resonant two-photon absorption within a rubidium cell and 780 nm pump light, a birefringent medium for 1.530 μm is induced that changes rapidly with frequency. The birefringence is exploited to build a spectrometer that is capable of measuring the Doppler shift of scattered photons.

Ultrafast time scale X-rotation of cold atom storage qubit using Rubidium clock states

NASA Astrophysics Data System (ADS)

Song, Yunheung; Lee, Han-Gyeol; Kim, Hyosub; Jo, Hanlae; Ahn, Jaewook

2017-04-01

Ultrafast-time-scale optical interaction is a local operation on the electronic subspace of an atom, thus leaving its nuclear state intact. However, because atomic clock states are maximally entangled states of the electronic and nuclear degrees of freedom, their entire Hilbert space should be accessible only with local operations and classical communications (LOCC). Therefore, it may be possible to achieve hyperfine qubit gates only with electronic transitions. Here we show an experimental implementation of ultrafast X-rotation of atomic hyperfine qubits, in which an optical Rabi oscillation induces a geometric phase between the constituent fine-structure states, thus bringing about the X-rotation between the two ground hyperfine levels. In experiments, cold atoms in a magneto-optical trap were controlled with a femtosecond laser pulse from a Ti:sapphire laser amplifier. Absorption imaging of the as-controlled atoms initially in the ground hyperfine state manifested polarization dependence, strongly agreeing with the theory. The result indicates that single laser pulse implementations of THz clock speed qubit controls are feasible for atomic storage qubits. Samsung Science and Technology Foundation [SSTF-BA1301-12].

Defect-free atomic array formation using the Hungarian matching algorithm

NASA Astrophysics Data System (ADS)

Lee, Woojun; Kim, Hyosub; Ahn, Jaewook

2017-05-01

Deterministic loading of single atoms onto arbitrary two-dimensional lattice points has recently been demonstrated, where by dynamically controlling the optical-dipole potential, atoms from a probabilistically loaded lattice were relocated to target lattice points to form a zero-entropy atomic lattice. In this atom rearrangement, how to pair atoms with the target sites is a combinatorial optimization problem: brute-force methods search all possible combinations so the process is slow, while heuristic methods are time efficient but optimal solutions are not guaranteed. Here, we use the Hungarian matching algorithm as a fast and rigorous alternative to this problem of defect-free atomic lattice formation. Our approach utilizes an optimization cost function that restricts collision-free guiding paths so that atom loss due to collision is minimized during rearrangement. Experiments were performed with cold rubidium atoms that were trapped and guided with holographically controlled optical-dipole traps. The result of atom relocation from a partially filled 7 ×7 lattice to a 3 ×3 target lattice strongly agrees with the theoretical analysis: using the Hungarian algorithm minimizes the collisional and trespassing paths and results in improved performance, with over 50% higher success probability than the heuristic shortest-move method.

Determination of the atomic density of rubidium-87

NASA Astrophysics Data System (ADS)

Zhao, Meng; Zhang, Kai; Chen, Li-Qing

2015-09-01

Atomic density is a basic and important parameter in quantum optics, nonlinear optics, and precision measurement. In the past few decades, several methods have been used to measure atomic density, such as thermionic effect, optical absorption, and resonance fluorescence. The main error of these experiments stemmed from depopulation of the energy level, self-absorption, and the broad bandwidth of the laser. Here we demonstrate the atomic density of 87Rb vapor in paraffin coated cell between 297 K and 334 K mainly using fluorescence measurement. Optical pumping, anti-relaxation coating, and absorption compensation approaches are used to decrease measurement error. These measurement methods are suitable for vapor temperature at dozens of degrees. The fitting function for the experimental data of 87Rb atomic density is given. Project supported by the Natural Science Foundation of China (Grant Nos. 11274118 and 11474095), the Innovation Program of Shanghai Municipal Education Commission of China (Grant No. 13ZZ036), and the Fundamental Research Funds for the Central Universities of China.

Λ-enhanced grey molasses on the D2 transition of Rubidium-87 atoms.

PubMed

Rosi, Sara; Burchianti, Alessia; Conclave, Stefano; Naik, Devang S; Roati, Giacomo; Fort, Chiara; Minardi, Francesco

2018-01-22

Laser cooling based on dark states, i.e. states decoupled from light, has proven to be effective to increase the phase-space density of cold trapped atoms. Dark-states cooling requires open atomic transitions, in contrast to the ordinary laser cooling used for example in magneto-optical traps (MOTs), which operate on closed atomic transitions. For alkali atoms, dark-states cooling is therefore commonly operated on the D 1 transition nS 1/2  → nP 1/2 . We show that, for 87 Rb, thanks to the large hyperfine structure separations the use of this transition is not strictly necessary and that "quasi-dark state" cooling is efficient also on the D 2 line, 5S 1/2  → 5P 3/2 . We report temperatures as low as (4.0 ± 0.3) μK and an increase of almost an order of magnitude in the phase space density with respect to ordinary laser sub-Doppler cooling.

Coherent scattering of near-resonant light by a dense, microscopic cloud of cold two-level atoms: Experiment versus theory

NASA Astrophysics Data System (ADS)

Jennewein, Stephan; Brossard, Ludovic; Sortais, Yvan R. P.; Browaeys, Antoine; Cheinet, Patrick; Robert, Jacques; Pillet, Pierre

2018-05-01

We measure the coherent scattering of low-intensity, near-resonant light by a cloud of laser-cooled two-level rubidium atoms with a size comparable to the wavelength of light. We isolate a two-level atomic structure by applying a 300-G magnetic field. We measure both the temporal and the steady-state coherent optical response of the cloud for various detunings of the laser and for atom numbers ranging from 5 to 100. We compare our results to a microscopic coupled-dipole model and to a multimode, paraxial Maxwell-Bloch model. In the low-intensity regime, both models are in excellent agreement, thus validating the Maxwell-Bloch model. Comparing to the data, the models are found in very good agreement for relatively low densities (n /k3≲0.1 ), while significant deviations start to occur at higher density. This disagreement indicates that light scattering in dense, cold atomic ensembles is still not quantitatively understood, even in pristine experimental conditions.

Quantum test of the equivalence principle for atoms in coherent superposition of internal energy states

PubMed Central

Rosi, G.; D'Amico, G.; Cacciapuoti, L.; Sorrentino, F.; Prevedelli, M.; Zych, M.; Brukner, Č.; Tino, G. M.

2017-01-01

The Einstein equivalence principle (EEP) has a central role in the understanding of gravity and space–time. In its weak form, or weak equivalence principle (WEP), it directly implies equivalence between inertial and gravitational mass. Verifying this principle in a regime where the relevant properties of the test body must be described by quantum theory has profound implications. Here we report on a novel WEP test for atoms: a Bragg atom interferometer in a gravity gradiometer configuration compares the free fall of rubidium atoms prepared in two hyperfine states and in their coherent superposition. The use of the superposition state allows testing genuine quantum aspects of EEP with no classical analogue, which have remained completely unexplored so far. In addition, we measure the Eötvös ratio of atoms in two hyperfine levels with relative uncertainty in the low 10−9, improving previous results by almost two orders of magnitude. PMID:28569742

Influence of the photon orbital angular momentum on electric dipole transitions: negative experimental evidence.

PubMed

Giammanco, F; Perona, A; Marsili, P; Conti, F; Fidecaro, F; Gozzini, S; Lucchesini, A

2017-01-15

We describe an experiment of atomic spectroscopy devoted to ascertaining whether the orbital angular momentum (OAM) of photons has the same property of interacting with atoms or molecules as occurs for the spin angular momentum (SAM). In our experiment, rubidium vapors are excited by means of laser radiation with different combinations of OAM and SAM, particularly selected to inhibit or enhance the fluorescence according to the selection rules for the electric dipole transitions between the fundamental state and the first excited doublet. Our results clearly show that an electric-dipole-type transition is insensitive to the OAM value, and provide an original validation of a problem long debated in theoretical works.

Observation of electromagnetically induced Talbot effect in an atomic system

NASA Astrophysics Data System (ADS)

Zhang, Zhaoyang; Liu, Xing; Zhang, Dan; Sheng, Jiteng; Zhang, Yiqi; Zhang, Yanpeng; Xiao, Min

2018-01-01

The electromagnetically induced Talbot effect (EITE) resulting from the repeated self-reconstruction of a spatially intensity-modulated probe field is experimentally demonstrated in a three-level atomic configuration. The probe beam is launched into an optically induced lattice (established by the interference of two coupling fields) inside a rubidium vapor cell and is diffracted by the electromagnetically induced grating that was formed. The diffraction pattern repeats itself at the planes of integer multiple Talbot lengths. In addition, a fractional EITE is also investigated. The experimental observations agree well with the theoretical predictions. This investigation may potentially pave the way for studying the nonlinear and quantum dynamical features that have been predicted for established periodic optical systems.

Application Status of Rubidium, Cesium and Research Situation of its Separation from Brine with Solvent Extraction

NASA Astrophysics Data System (ADS)

Shi, Zhen; Du, Xuemin; Wang, Shiqiang; Guo, Yafei; Deng, Tianlong

2017-12-01

Rubidium, cesium and its compounds play an important role in traditional and high-tech fields. This paper focuses on the research status of separation rubidium and cesium in brine using solvent extraction, and briefly introduced the characteristics of this method, which can be used to realize industrial production of rubidium and cesium from brine.

A low-power reversible alkali atom source

NASA Astrophysics Data System (ADS)

Kang, Songbai; Mott, Russell P.; Gilmore, Kevin A.; Sorenson, Logan D.; Rakher, Matthew T.; Donley, Elizabeth A.; Kitching, John; Roper, Christopher S.

2017-06-01

An electrically controllable, solid-state, reversible device for sourcing and sinking alkali vapor is presented. When placed inside an alkali vapor cell, both an increase and decrease in the rubidium vapor density by a factor of two are demonstrated through laser absorption spectroscopy on 10-15 s time scales. The device requires low voltage (5 V), low power (<3.4 mW peak power), and low energy (<10.7 mJ per 10 s pulse). The absence of oxygen emission during operation is shown through residual gas analysis, indicating that Rb is not lost through chemical reaction but rather by ion transport through the designed channel. This device is of interest for atomic physics experiments and, in particular, for portable cold-atom systems where dynamic control of alkali vapor density can enable advances in science and technology.

Pattern Formations for Optical Switching Using Cold Atoms as a Nonlinear Medium

NASA Astrophysics Data System (ADS)

Schmittberger, Bonnie; Greenberg, Joel; Gauthier, Daniel

2011-05-01

The study of spatio-temporal pattern formation in nonlinear optical systems has both led to an increased understanding of nonlinear dynamics as well as given rise to sensitive new methods for all-optical switching. Whereas the majority of past experiments utilized warm atomic vapors as nonlinear media, we report the first observation of an optical instability leading to pattern formation in a cloud of cold Rubidium atoms. When we shine a pair of counterpropagating pump laser beams along the pencil-shaped cloud's long axis, new beams of light are generated along cones centered on the trap. This generated light produces petal-like patterns in the plane orthogonal to the pump beams that can be used for optical switching. We gratefully acknowledge the financial support of the NSF through Grant #PHY-0855399 and the DARPA Slow Light Program.

The Kinetics of Ouabain Inhibition and the Partition of Rubidium Influx in Human Red Blood Cells

PubMed Central

Beauge, L. A.; Adragna, Norma

1971-01-01

In the development of ouabain inhibition of rubidium influx in human red blood cells a time lag can be detected which is a function of at least three variables: the concentrations of external sodium, rubidium, and ouabain. The inhibition is antagonized by rubidium and favored by sodium. Similar considerations could be applied to the binding of ouabain to membrane sites. The total influx of rubidium as a function of external rubidium concentration can be separated into two components: (a) a linear uptake not affected by external sodium or ouabain and not requiring an energy supply, and (b) a saturable component. The latter component, on the basis of the different effects of the aforementioned factors, can be divided into three fractions. The first is ouabain-sensitive, inhibited by external sodium at low rubidium, and requires an energy supply; this represents about 70–80% of the total uptake and is related to the active sodium extrusion mechanism. The second is ouabain-insensitive, activated by external sodium over the entire range of rubidium concentrations studied, and dependent on internal ATP; this represents about 15% of the total influx; it could be coupled to an active sodium extrusion or belong to a rubidium-potassium exchange. The third, which can be called residual influx, is ouabain-insensitive, unaffected by external sodium, and independent of internal ATP; this represents about 10–20% of the total influx. PMID:5553102

Demonstration of improved sensitivity of echo interferometers to gravitational acceleration

NASA Astrophysics Data System (ADS)

Mok, C.; Barrett, B.; Carew, A.; Berthiaume, R.; Beattie, S.; Kumarakrishnan, A.

2013-08-01

We have developed two configurations of an echo interferometer that rely on standing-wave excitation of a laser-cooled sample of rubidium atoms. Both configurations can be used to measure acceleration a along the axis of excitation. For a two-pulse configuration, the signal from the interferometer is modulated at the recoil frequency and exhibits a sinusoidal frequency chirp as a function of pulse spacing. In comparison, for a three-pulse stimulated-echo configuration, the signal is observed without recoil modulation and exhibits a modulation at a single frequency as a function of pulse spacing. The three-pulse configuration is less sensitive to effects of vibrations and magnetic field curvature, leading to a longer experimental time scale. For both configurations of the atom interferometer (AI), we show that a measurement of acceleration with a statistical precision of 0.5% can be realized by analyzing the shape of the echo envelope that has a temporal duration of a few microseconds. Using the two-pulse AI, we obtain measurements of acceleration that are statistically precise to 6 parts per million (ppm) on a 25 ms time scale. In comparison, using the three-pulse AI, we obtain measurements of acceleration that are statistically precise to 0.4 ppm on a time scale of 50 ms. A further statistical enhancement is achieved by analyzing the data across the echo envelope so that the statistical error is reduced to 75 parts per billion (ppb). The inhomogeneous field of a magnetized vacuum chamber limited the experimental time scale and resulted in prominent systematic effects. Extended time scales and improved signal-to-noise ratio observed in recent echo experiments using a nonmagnetic vacuum chamber suggest that echo techniques are suitable for a high-precision measurement of gravitational acceleration g. We discuss methods for reducing systematic effects and improving the signal-to-noise ratio. Simulations of both AI configurations with a time scale of 300 ms suggest that an optimized experiment with improved vibration isolation and atoms selected in the mF=0 state can result in measurements of g statistically precise to 0.3 ppb for the two-pulse AI and 0.6 ppb for the three-pulse AI.

Compact diffraction grating laser wavemeter with sub-picometer accuracy and picowatt sensitivity using a webcam imaging sensor.

PubMed

White, James D; Scholten, Robert E

2012-11-01

We describe a compact laser wavelength measuring instrument based on a small diffraction grating and a consumer-grade webcam. With just 1 pW of optical power, the instrument achieves absolute accuracy of 0.7 pm, sufficient to resolve individual hyperfine transitions of the rubidium absorption spectrum. Unlike interferometric wavemeters, the instrument clearly reveals multimode laser operation, making it particularly suitable for use with external cavity diode lasers and atom cooling and trapping experiments.

Optically Pumped Atomic Rubidium Lasers: Two-Photon and Exciplex Excitation Mechanisms

DTIC Science & Technology

2013-06-01

gain is very high with photon build-up times of 1−3.7 ns. Laser induced heating and subsequent condensation of alkali vapor in the heat pipe...encouragement during our time in classes, and recommendations while in the lab were invaluable. Finally, I want to thank the High Energy Laser Joint...intensity. The more non-traditional method is to use a single laser pulse to sketch out all needed energies. A photon build-up time was determined from

Light-Shifts of an Integrated Filter-Cell Rubidium Atomic Clock

DTIC Science & Technology

2015-05-25

the light-shift coefficient for two different rf- discharge lamps (i.e., a pure 87Rb lamp and a lamp filled with the natural Rb isotope abundance...for the Galileo Rb clock under the assumption of a natural (or 85Rb isotopically enriched) rf- discharge lamp for the Galileo clock. I...satellites [14]. 6.8347… GHz 85Rb Filter Cell Cell Resonance Photodiode Microwave Cavity 87Rb Discharge Lamp 87Rb & N2 Rb & Xe, Kr Optical Pumping 87Rb

Spin dynamics and Kondo physics in optical tweezers

NASA Astrophysics Data System (ADS)

Lin, Yiheng; Lester, Brian J.; Brown, Mark O.; Kaufman, Adam M.; Long, Junling; Ball, Randall J.; Isaev, Leonid; Wall, Michael L.; Rey, Ana Maria; Regal, Cindy A.

2016-05-01

We propose to use optical tweezers as a toolset for direct observation of the interplay between quantum statistics, kinetic energy and interactions, and thus implement minimum instances of the Kondo lattice model in systems with few bosonic rubidium atoms. By taking advantage of strong local exchange interactions, our ability to tune the spin-dependent potential shifts between the two wells and complete control over spin and motional degrees of freedom, we design an adiabatic tunneling scheme that efficiently creates a spin-singlet state in one well starting from two initially separated atoms (one atom per tweezer) in opposite spin state. For three atoms in a double-well, two localized in the lowest vibrational mode of each tweezer and one atom in an excited delocalized state, we plan to use similar techniques and observe resonant transfer of two-atom singlet-triplet states between the wells in the regime when the exchange coupling exceeds the mobile atom hopping. Moreover, we argue that such three-atom double-tweezers could potentially be used for quantum computation by encoding logical qubits in collective spin and motional degrees of freedom. Current address: Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.

Extraction of rubidium from natural resources

NASA Astrophysics Data System (ADS)

Ertan, Bengü

2017-04-01

Rubidium is a rare alkali metal in the first group of periodic table. It has some exclusive properties like softness, ductility, malleability, strong chemical and photo-emissive activity, low melting point, easy ionization. So it is used many of applications such that optical and laser technology, electronics, telecommunications, biomedical, space technology, academic research especially quantum mechanics-based computing devices. Attention of rubidium in relation to its uses will increase in the near future. Rubidium does not have any mineral that is the main component. It is produced as minor quantities from lithium or cesium-rich minerals and natural brines. However, there are a few researches on the extraction of rubidium from mine tailings. It is difficult extraction or concentration of rubidium from these resources. Because they require a series of physical and chemical treatments and cost expensive. Efficient, cheap and friendly of environment methods for the recovery of this metal are being investigated.

Poly[(μ-3,5-dinitro­benzoato)(μ-3,5-dinitro­benzoic acid)rubidium

PubMed Central

Miao, Yanqing; Fan, Tao

2011-01-01

The asymmetric unit of the title compound, [Rb(C7H3N2O6)(C7H4N2O6)]n, comprises an Rb+ cation, a 3,5-dinitro­benzoate anion and a 3,5-dinitro­benzoic acid ligand. The Rb+ cation is nine-coordinated by O atoms from four 3,5-dinitro­benzoate anions and three neutral 3,5-dinitro­benzoic acid ligands. The metal atom is firstly linked by four bridging carboxyl groups, forming a binuclear motif, which is further linked by the nitro groups into a two-dimensional framework along the [110] direction. A short O—H⋯O hydrogen bond between two adjacent carboxy/carboxylate groups occurs. PMID:22090832

Data on inelastic processes in low-energy potassium-hydrogen and rubidium-hydrogen collisions

NASA Astrophysics Data System (ADS)

Yakovleva, S. A.; Barklem, P. S.; Belyaev, A. K.

2018-01-01

Two sets of rate coefficients for low-energy inelastic potassium-hydrogen and rubidium-hydrogen collisions were computed for each collisional system based on two model electronic structure calculations, performed by the quantum asymptotic semi-empirical and the quantum asymptotic linear combinations of atomic orbitals (LCAO) approaches, followed by quantum multichannel calculations for the non-adiabatic nuclear dynamics. The rate coefficients for the charge transfer (mutual neutralization, ion-pair formation), excitation and de-excitation processes are calculated for all transitions between the five lowest lying covalent states and the ionic states for each collisional system for the temperature range 1000-10 000 K. The processes involving higher lying states have extremely low rate coefficients and, hence, are neglected. The two model calculations both single out the same partial processes as having large and moderate rate coefficients. The largest rate coefficients correspond to the mutual neutralization processes into the K(5s 2S) and Rb(4d 2D) final states and at temperature 6000 K have values exceeding 3 × 10-8 cm3 s-1 and 4 × 10-8 cm3 s-1, respectively. It is shown that both the semi-empirical and the LCAO approaches perform equally well on average and that both sets of atomic data have roughly the same accuracy. The processes with large and moderate rate coefficients are likely to be important for non-LTE modelling in atmospheres of F, G and K-stars, especially metal-poor stars.

Electron-impact ionization cross sections out of the ground and 6P2 excited states of cesium

NASA Astrophysics Data System (ADS)

Łukomski, M.; Sutton, S.; Kedzierski, W.; Reddish, T. J.; Bartschat, K.; Bartlett, P. L.; Bray, I.; Stelbovics, A. T.; McConkey, J. W.

2006-09-01

An atom trapping technique for determining absolute, total ionization cross sections (TICS) out of an excited atom is presented. The unique feature of our method is in utilizing Doppler cooling of neutral atoms to determine ionization cross sections. This fluorescence-monitoring experiment, which is a variant of the “trap loss” technique, has enabled us to obtain the experimental electron impact ionization cross sections out of the Cs 6P3/22 state between 7eV and 400eV . CCC, RMPS, and Born theoretical results are also presented for both the ground and excited states of cesium and rubidium. In the low energy region (<11eV) where best agreement between these excited state measurements and theory might be expected, a discrepancy of approximately a factor of five is observed. Above this energy there are significant contributions to the TICS from both autoionization and multiple ionization.

Precision measurement of transition matrix elements via light shift cancellation.

PubMed

Herold, C D; Vaidya, V D; Li, X; Rolston, S L; Porto, J V; Safronova, M S

2012-12-14

We present a method for accurate determination of atomic transition matrix elements at the 10(-3) level. Measurements of the ac Stark (light) shift around "magic-zero" wavelengths, where the light shift vanishes, provide precise constraints on the matrix elements. We make the first measurement of the 5s - 6p matrix elements in rubidium by measuring the light shift around the 421 and 423 nm zeros through diffraction of a condensate off a sequence of standing wave pulses. In conjunction with existing theoretical and experimental data, we find 0.3235(9)ea(0) and 0.5230(8)ea(0) for the 5s - 6p(1/2) and 5s - 6p(3/2) elements, respectively, an order of magnitude more accurate than the best theoretical values. This technique can provide needed, accurate matrix elements for many atoms, including those used in atomic clocks, tests of fundamental symmetries, and quantum information.

Quantum memory in warm rubidium vapor with buffer gas.

PubMed

Bashkansky, Mark; Fatemi, Fredrik K; Vurgaftman, Igor

2012-01-15

The realization of quantum memory using warm atomic vapor cells is appealing because of their commercial availability and the perceived reduction in experimental complexity. In spite of the ambiguous results reported in the literature, we demonstrate that quantum memory can be implemented in a single cell with buffer gas using the geometry where the write and read beams are nearly copropagating. The emitted Stokes and anti-Stokes photons display cross-correlation values greater than 2, characteristic of quantum states, for delay times up to 4 μs.

Cold Rydberg molecules

NASA Astrophysics Data System (ADS)

Raithel, Georg

2017-04-01

Cold atomic systems have opened new frontiers in atomic and molecular physics, including several types of Rydberg molecules. Three types will be reviewed. Long-range Rydberg-ground molecules, first predicted in and observed in, are formed via low-energy electron scattering of the Rydberg electron from a ground-state atom within the Rydberg atom's volume. The binding mostly arises from S- and P-wave triplet scattering. We use a Fermi model that includes S-wave and P-wave singlet and triplet scattering, the fine structure coupling of the Rydberg atom and the hyperfine structure coupling of the 5S1/2 atom (in rubidium). The hyperfine structure gives rise to mixed singlet-triplet potentials for both low-L and high-L Rydberg molecules. A classification into Hund's cases will be discussed. The talk further includes results on adiabatic potentials and adiabatic states of Rydberg-Rydberg molecules in Rb and Cs. These molecules, which have even larger bonding length than Rydberg-ground molecules, are formed via electrostatic multipole interactions. The leading interaction of neutral Rydberg-Rydberg molecules is dipole-dipole, while for ionic Rydberg molecules it is dipole-monopole. Higher-order terms are discussed. FUNDING: NSF (PHY-1506093), NNSF of China (61475123).

One nanosecond time synchronization using series and GPS

NASA Technical Reports Server (NTRS)

Buennagel, A. A.; Spitzmesser, D. J.; Young, L. E.

1983-01-01

Subnanosecond time sychronization between two remote rubidium frequency standards is verified by a traveling clock comparison. Using a novel, code ignorant Global Positioning System (GPS) receiver developed at JPL, the SERIES geodetic baseline measurement system is applied to establish the offset between the 1 Hz. outputs of the remote standards. Results of the two intercomparison experiments to date are presented as well as experimental details.

Optical control of resonant light transmission for an atom-cavity system

NASA Astrophysics Data System (ADS)

Sharma, Arijit; Ray, Tridib; Sawant, Rahul V.; Sheikholeslami, G.; Rangwala, S. A.; Budker, D.

2015-04-01

We demonstrate the manipulation of transmitted light through an optical Fabry-Pérot cavity, built around a spectroscopy cell containing enriched rubidium vapor. Light resonant with the 87RbD2 (F =2 ,F =1 ) ↔F' manifold is controlled by the transverse intersection of the cavity mode by another resonant light beam. The cavity transmission can be suppressed or enhanced depending on the coupling of atomic states due to the intersecting beams. The extreme manifestation of the cavity-mode control is the precipitous destruction (negative logic switching) or buildup (positive logic switching) of the transmitted light intensity on intersection of the transverse control beam with the cavity mode. Both the steady-state and transient responses are experimentally investigated. The mechanism behind the change in cavity transmission is discussed in brief.

Pulse Propagation Effects in Optical 2D Fourier-Transform Spectroscopy: Theory.

PubMed

Spencer, Austin P; Li, Hebin; Cundiff, Steven T; Jonas, David M

2015-04-30

A solution to Maxwell's equations in the three-dimensional frequency domain is used to calculate rephasing two-dimensional Fourier transform (2DFT) spectra of the D2 line of atomic rubidium vapor in argon buffer gas. Experimental distortions from the spatial propagation of pulses through the sample are simulated in 2DFT spectra calculated for the homogeneous Bloch line shape model. Spectral features that appear at optical densities of up to 3 are investigated. As optical density increases, absorptive and dispersive distortions start with peak shape broadening, progress to peak splitting, and ultimately result in a previously unexplored coherent transient twisting of the split peaks. In contrast to the low optical density limit, where the 2D peak shape for the Bloch model depends only on the total dephasing time, these distortions of the 2D peak shape at finite optical density vary with the waiting time and the excited state lifetime through coherent transient effects. Experiment-specific conditions are explored, demonstrating the effects of varying beam overlap within the sample and of pseudo-time domain filtering. For beam overlap starting at the sample entrance, decreasing the length of beam overlap reduces the line width along the ωτ axis but also reduces signal intensity. A pseudo-time domain filter, where signal prior to the center of the last excitation pulse is excluded from the FID-referenced 2D signal, reduces propagation distortions along the ωt axis. It is demonstrated that 2DFT rephasing spectra cannot take advantage of an excitation-detection transformation that can eliminate propagation distortions in 2DFT relaxation spectra. Finally, the high optical density experimental 2DFT spectrum of rubidium vapor in argon buffer gas [J. Phys. Chem. A 2013, 117, 6279-6287] is quantitatively compared, in line width, in depth of peak splitting, and in coherent transient peak twisting, to a simulation with optical density higher than that reported.

Dual-Beam Atom Laser Driven by Spinor Dynamics

NASA Technical Reports Server (NTRS)

Thompson, Robert; Lundblad, Nathan; Maleki, Lute; Aveline, David

2007-01-01

An atom laser now undergoing development simultaneously generates two pulsed beams of correlated Rb-87 atoms. (An atom laser is a source of atoms in beams characterized by coherent matter waves, analogous to a conventional laser, which is a source of coherent light waves.) The pumping mechanism of this atom laser is based on spinor dynamics in a Bose-Einstein condensate. By virtue of the angular-momentum conserving collisions that generate the two beams, the number of atoms in one beam is correlated with the number of atoms in the other beam. Such correlations are intimately linked to entanglement and squeezing in atomic ensembles, and atom lasers like this one could be used in exploring related aspects of Bose-Einstein condensates, and as components of future sensors relying on atom interferometry. In this atom-laser apparatus, a Bose-Einstein condensate of about 2 x 10(exp 6) Rb-87 atoms at a temperature of about 120 micro-K is first formed through all-optical means in a relatively weak singlebeam running-wave dipole trap that has been formed by focusing of a CO2-laser beam. By a technique that is established in the art, the trap is loaded from an ultrahigh-vacuum magnetooptical trap that is, itself, loaded via a cold atomic beam from an upstream two-dimensional magneto-optical trap that resides in a rubidium-vapor cell that is differentially pumped from an adjoining vacuum chamber, wherein are performed scientific observations of the beams ultimately generated by the atom laser.

Stabilization of a self-referenced, prism-based, Cr:forsterite laser frequency comb using an intracavity prism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tillman, Karl A.; Thapa, Rajesh; Knabe, Kevin

2009-12-20

The frequency comb from a prism-based Cr:forsterite laser has been frequency stabilized using intracavity prism insertion and pump power modulation. Absolute frequency measurements of a CW fiber laser stabilized to the P(13) transition of acetylene demonstrate a fractional instability of {approx}2x10{sup -11} at a 1 s gate time, limited by a commercial Global Positioning System (GPS)-disciplined rubidium oscillator. Additionally, absolute frequency measurements made simultaneously using a second frequency comb indicate relative instabilities of 3x10{sup -12} for both combs for a 1 s gate time. Estimations of the carrier-envelope offset frequency linewidth based on relative intensity noise and the response dynamicsmore » of the carrier-envelope offset to pump power changes confirm the observed linewidths.« less

Rubidium 87 gas cell studies, phase 2. [design and characteristics of rubidium maser

NASA Technical Reports Server (NTRS)

Vanier, J.

1974-01-01

The design, development, and characteristics of a rubidium 87 maser are discussed. The design of a receiver capable of locking a crystal oscillator to the maser signal is reported. The subjects considered are: (1) maser construction, (2) maser control electronics, (3) the characteristics of the receiver, and (4) results of experimental maser tests.

LIBS and LIFS for rapid detection of Rb traces in blood

NASA Astrophysics Data System (ADS)

Al-Jeffery, Mohammad O.; Telle, Helmut H.

2002-05-01

Tests that can quickly and efficiently detect traces of illegal performance enhancing drugs are becoming essential. Certain performance enhancing drugs lead to an increase in the count of red blood cells. The proportion of blood made up of red cells is normally around 42 percent. At least 90 percent of Rubidium measured in whole blood is located in the red blood cells. If Rubidium Chloride (RbCl) is given to an athlete around 30 minutes before competing and a sample of their blood (a drop on a filter) was subsequently tested for Rubidium content, the test will give a direct indication of the red blood cell count. In this contribution, we describe an efficient and fast test based on spectroscopic techniques that can be used to detect trace levels of Rubidium. Our experiments employed Rubidium nitride (RbNO3) and trace levels down to 0.3 percent were successfully detected.

Investigation of Rubidium Hyperfine Structure Frequency Stabilization Mechanisms.

DTIC Science & Technology

1984-08-01

Frueholtz, and C. H. Volk, Phys. Rev. A 27, 1914 (1983). 4. C. Cohen-Tannoudji, Metrologia 13, 161 (1977). 5. W. Happer, and A. C. Tam, Phys. Rev. A 16, 1877...w U C) ED W mF w c M0 -0 Dm U(i2 DOW V) ZivF 00. LA *I U-(JL OLLIAJ - (I 0 7 a I I ~w..-..- ~ * * ~ -~.’,** ~-, .*h4w.’.-* .- ,-~-. . .- * 8

Rubidium frequency standard test program for NAVSTAR GPS

NASA Technical Reports Server (NTRS)

Koide, F.; Dederich, D. J.

1978-01-01

Test data of the RFS Program in the Production phase and computer automation are presented, as an essential element in the evaluation of the RFS performance in a simulated spacecraft environment. Typical production test data will be discussed for stabilities from 1 to 100,000 seconds averaging time and simulated time error accumulation test. Also, design considerations in developing the RFS test systems for the acceptance test in production are discussed.

"Chemical contraction" in rubidium-bismuth melts

NASA Astrophysics Data System (ADS)

Khairulin, R. A.; Abdullaev, R. N.; Stankus, S. V.

2017-10-01

The density and thermal expansion of liquid rubidium and rubidium-bismuth alloy containing 25.0 at % Bi were measured by the gamma-ray attenuation technique at temperatures from liquidus to 1000 K. The results of this study were compared with the data obtained by other authors. The molar volume of the Rb75Bi25 melt strongly deviates from the additivity rule for ideal solutions.

Materials screening tests for the krypton-85 storage development program

NASA Astrophysics Data System (ADS)

Nagata, P. K.

1981-04-01

The results of a materials testing program for krypton-85 storage techniques are reported. Corrosion and stress corrosion tests were performed on a variety of materials including AISI 4130, Type 316 SS, Type 304 SS, Type 310 SS, Nitronic 50, and alloy A286. Test environments were high-purity liquid rubidium, liquid rubidium contaminated with oxygen, and rubidium hydroxide. Oxygen and water contaminations in liquid rubidium were found to greatly increase both general and localized corrosion of the materials tested. Alloy A286, Type 304 SS, and AISI 4130 were eliminated as candidate materials due to their susceptibility to general corrosion and stress corrosion cracking.

Real-time interferometric diagnostics of rubidium plasma

NASA Astrophysics Data System (ADS)

Djotyan, G. P.; Bakos, J. S.; Kedves, M. Á.; Ráczkevi, B.; Dzsotjan, D.; Varga-Umbrich, K.; Sörlei, Zs.; Szigeti, J.; Ignácz, P.; Lévai, P.; Czitrovszky, A.; Nagy, A.; Dombi, P.; Rácz, P.

2018-03-01

A method of interferometric real-time diagnostics is developed and applied to rubidium plasma created by strong laser pulses in the femtosecond duration range at different initial rubidium vapor densities using a Michelson-type interferometer. A cosine fit with an exponentially decaying relative phase is applied to the obtained time-dependent interferometry signals to measure the density-length product of the created plasma and its recombination time constant. The presented technique may be applicable for real-time measurements of rubidium plasma dynamics in the AWAKE experiment at CERN, as well as for real-time diagnostics of plasmas created in different gaseous media and on surfaces of solid targets.

Measurements of the energy distribution of a high brightness rubidium ion beam.

PubMed

Ten Haaf, G; Wouters, S H W; Nijhof, D F J; Mutsaers, P H A; Vredenbregt, E J D

2018-07-01

The energy distribution of a high brightness rubidium ion beam, which is intended to be used as the source for a focused ion beam instrument, is measured with a retarding field analyzer. The ions are created from a laser-cooled and compressed atomic beam by two-step photoionization in which the ionization laser power is enhanced in a build-up cavity. Particle tracing simulations are performed to ensure the analyzer is able to resolve the distribution. The lowest achieved full width 50% energy spread is (0.205 ± 0.006) eV, which is measured at a beam current of 9 pA. The energy spread originates from the variation in the ionization position of the ions which are created inside an extraction electric field. This extraction field is essential to limit disorder-induced heating which can decrease the ion beam brightness. The ionization position distribution is limited by a tightly focused excitation laser beam. Energy distributions are measured for various ionization and excitation laser intensities and compared with calculations based on numerical solutions of the optical Bloch equations including ionization. A good agreement is found between measurements and calculations. Copyright © 2018 Elsevier B.V. All rights reserved.

Real-space imaging of a topologically protected edge state with ultracold atoms in an amplitude-chirped optical lattice

PubMed Central

Leder, Martin; Grossert, Christopher; Sitta, Lukas; Genske, Maximilian; Rosch, Achim; Weitz, Martin

2016-01-01

To describe a mobile defect in polyacetylene chains, Su, Schrieffer and Heeger formulated a model assuming two degenerate energy configurations that are characterized by two different topological phases. An immediate consequence was the emergence of a soliton-type edge state located at the boundary between two regions of different configurations. Besides giving first insights in the electrical properties of polyacetylene materials, interest in this effect also stems from its close connection to states with fractional charge from relativistic field theory. Here, using a one-dimensional optical lattice for cold rubidium atoms with a spatially chirped amplitude, we experimentally realize an interface between two spatial regions of different topological order in an atomic physics system. We directly observe atoms confined in the edge state at the intersection by optical real-space imaging and characterize the state as well as the size of the associated energy gap. Our findings hold prospects for the spectroscopy of surface states in topological matter and for the quantum simulation of interacting Dirac systems. PMID:27767054

The 25th Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting

NASA Technical Reports Server (NTRS)

Sydnor, Richard L. (Editor)

1994-01-01

Papers in the following categories are presented: recent developments in rubidium, cesium, and hydrogen-based frequency standards, and in cryogenic and trapped-ion technology; international and transnational applications of precise time and time interval (PTTI) technology with emphasis on satellite laser tracking networks, GLONASS timing, intercomparison of national time scales and international telecommunication; applications of PTTI technology to the telecommunications, power distribution, platform positioning, and geophysical survey industries; application of PTTI technology to evolving military communications and navigation systems; and dissemination of precise time and frequency by means of GPS, GLONASS, MILSTAR, LORAN, and synchronous communications satellites.

A multiplexed quantum memory.

PubMed

Lan, S-Y; Radnaev, A G; Collins, O A; Matsukevich, D N; Kennedy, T A; Kuzmich, A

2009-08-03

A quantum repeater is a system for long-distance quantum communication that employs quantum memory elements to mitigate optical fiber transmission losses. The multiplexed quantum memory (O. A. Collins, S. D. Jenkins, A. Kuzmich, and T. A. B. Kennedy, Phys. Rev. Lett. 98, 060502 (2007)) has been shown theoretically to reduce quantum memory time requirements. We present an initial implementation of a multiplexed quantum memory element in a cold rubidium gas. We show that it is possible to create atomic excitations in arbitrary memory element pairs and demonstrate the violation of Bell's inequality for light fields generated during the write and read processes.

Effect of soil temperature on optical frequency transfer through unidirectional dense-wavelength-division-multiplexing fiber-optic links.

PubMed

Pinkert, T J; Böll, O; Willmann, L; Jansen, G S M; Dijck, E A; Groeneveld, B G H M; Smets, R; Bosveld, F C; Ubachs, W; Jungmann, K; Eikema, K S E; Koelemeij, J C J

2015-02-01

Results of optical frequency transfer over a carrier-grade dense-wavelength-division-multiplexing (DWDM) optical fiber network are presented. The relation between soil temperature changes on a buried optical fiber and frequency changes of an optical carrier through the fiber is modeled. Soil temperatures, measured at various depths by the Royal Netherlands Meteorology Institute (KNMI) are compared with observed frequency variations through this model. A comparison of a nine-day record of optical frequency measurements through the 2×298  km fiber link with soil temperature data shows qualitative agreement. A soil temperature model is used to predict the link stability over longer periods (days-months-years). We show that optical frequency dissemination is sufficiently stable to distribute and compare, e.g., rubidium frequency standards over standard DWDM optical fiber networks using unidirectional fibers.

Cold Rydberg molecules

NASA Astrophysics Data System (ADS)

Raithel, Georg; Zhao, Jianming

2017-04-01

Cold atomic systems have opened new frontiers at the interface of atomic and molecular physics. These include research on novel types of Rydberg molecules. Three types of molecules will be reviewed. Long-range, homonuclear Rydberg molecules, first predicted in [1] and observed in [2], are formed via low-energy electron scattering of the Rydberg electron from a ground-state atom within the Rydberg atom's volume. The binding mostly arises from S- and P-wave triplet scattering. We use a Fermi model that includes S-wave and P-wave singlet and triplet scattering, the fine structure coupling of the Rydberg atom and the hyperfine structure coupling of the 5S1/2 atom (in rubidium [3]). The hyperfine structure gives rise to mixed singlet-triplet potentials for both low-L and high-L Rydberg molecules [3]. A classification into Hund's cases [3, 4, 5] will be discussed. The talk further includes results on adiabatic potentials and adiabatic states of Rydberg-Rydberg molecules in Rb and Cs. These molecules, which have even larger bonding length than Rydberg-ground molecules, are formed via electrostatic multipole interactions. The leading interaction term of neutral Rydberg-Rydberg molecules is between two dipoles, while for ionic Rydberg molecules it is between a dipole and a monopole. NSF (PHY-1506093), NNSF of China (61475123).

Radiation Hardness of Efratom M-100 Rubidium Frequency Standard

DTIC Science & Technology

1982-12-01

h i ghes t f l uence o f 6.15 x 1012n/crn2 t h e norma l i zed ac pho tocur ren ts were about 702 o f t he normal ized dc photo- c u r r...100, FRK, M-1000. Pyrex ( t r ade name of Corning Glass) . e Cells produced i n Munich use Schott Duran 50 g lass which i s nearly ident ica l

Coherent Population Trapping and Optical Ramsey Interference for Compact Rubidium Clock Development

NASA Astrophysics Data System (ADS)

Warren, Zachary Aron

Coherent population trapping (CPT) and optical Ramsey interference provide new avenues for developing compact, high-performance atomic clocks. In this work, I have studied the fundamental aspects of CPT and optical Ramsey interference for Raman clock development. This thesis research is composed of two parts: theoretical and experimental studies. The theoretical component of the research was initially based on pre-existing atomic models of a three-level ?-type system in which the phenomena of CPT and Ramsey interference are formed. This model served as a starting point for studying basic characteristics of CPT and Ramsey interference such as power dependence of CPT, effects of average detuning, and ground-state decoherence on linewidth, which directly impact the performance of the Raman clock. The basic three-level model was also used to model pulsed CPT excitation and measure light shift in Ramsey interference which imposes a fundamental limit on the long-term frequency stability of the Raman clock. The theoretical calculations illustrate reduction (or suppression) of light shift in Ramsey interference as an important advantage over CPT for Raman clock development. To make the model more accurate than an ideal three-level system, I developed a comprehensive atomic model using density-matrix equations including all sixteen Zeeman sublevels in the D1 manifold of 87Rb atoms in a vapor medium. The multi-level atomic model has been used for investigating characteristics of CPT and Ramsey interference under different optical excitation schemes pertaining to the polarization states of the frequency-modulated CPT beam in a Raman clock. It is also used to study the effects of axial and traverse magnetic fields on the contrast of CPT and Ramsey interference. More importantly, the multi-level atomic model is also used to accurately calculate light shift in Ramsey interference in the D1 manifold of 87Rb atoms by taking into account all possible off-resonant excitations and the ground-state decoherence among the Zeeman sublevels. Light shift suppression in Ramsey interference with pulse saturation is also found to be evident in this comprehensive model. In the experimental component of the research, I designed a prototype of the Raman clock using a small (2 cm in length), buffer-gas filled, and isotopically pure 87Rb cell. A fiber-coupled waveguide electro-optic modulator was used to generate the frequency-modulated CPT beam for the experiments. The experimental setup was operated either by continuous excitation or pulsed excitation for experimentally characterizing CPT and Ramsey interference under different experimental conditions and for testing different optical excitation schemes which were investigated theoretically. Several iterations of the clock physics package were developed in order to attain better frequency stability performance in the Raman clock. The experimental work also provided a basis to develop a new repeated-query technique for producing an ultra-narrow linewidth central fringe with a high S/N ratio, and suppressing the side fringes in Ramsey interference. The above described research was carried out keeping in mind compact, high-performance clock development, which relies on technologies that can be miniaturized. Vapor cell based atomic clocks are ideal candidates for compact clock technology. The CPT phenomenon, observed by Raman excitation in a vapor medium, is a promising candidate for compact, high-performance Raman clock development. However, atom-field interaction involved in a vapor medium is often more complex than other media such as cold atom or atomic beam. It is difficult to model this interaction in order to predict its influence on CPT characteristics and, hence, the performance of the Raman clock. This dissertation addresses one such problem by developing a comprehensive atomic model to investigate light shift and modification of light shift in the Raman clock, particularly with pulsed excitation. It demonstrates a clear possibility of reducing (or suppressing) the light shift associated with Ramsey interference in a vapor medium for achieving higher frequency stability in the Raman clock. Additionally, theoretical comparisons of various optical excitation techniques have been calculated to demonstrate the relative strengths and weaknesses of different schemes for Raman clock development. (Abstract shortened by ProQuest.).

Highly precise stabilization of intracavity prism-based Er:fiber frequency comb using optical-microwave phase detector.

PubMed

Zhang, Shuangyou; Wu, Jiutao; Leng, Jianxiao; Lai, Shunnan; Zhao, Jianye

2014-11-15

In this Letter, we demonstrate a fully stabilized Er:fiber frequency comb by using a fiber-based, high-precision optical-microwave phase detector. To achieve high-precision and long-term phase locking of the repetition rate to a microwave reference, frequency control techniques (tuning pump power and cavity length) are combined together as its feedback. Since the pump power has been used for stabilization of the repetition rate, we introduce a pair of intracavity prisms as a regulator for carrier-envelope offset frequency, thereby phase locking one mode of the comb to the rubidium saturated absorption transition line. The stabilized comb performs the same high stability as the reference for the repetition rate and provides a residual frequency instability of 3.6×10(-13) for each comb mode. The demonstrated stabilization scheme could provide a high-precision comb for optical communication, direct frequency comb spectroscopy.

Ultracold Mixtures of Rubidium and Ytterbium for Open Quantum System Engineering

NASA Astrophysics Data System (ADS)

Herold, Creston David

Exquisite experimental control of quantum systems has led to sharp growth of basic quantum research in recent years. Controlling dissipation has been crucial in producing ultracold, trapped atomic samples. Recent theoretical work has suggested dissipation can be a useful tool for quantum state preparation. Controlling not only how a system interacts with a reservoir, but the ability to engineer the reservoir itself would be a powerful platform for open quantum system research. Toward this end, we have constructed an apparatus to study ultracold mixtures of rubidium (Rb) and ytterbium (Yb). We have developed a Rb-blind optical lattice at 423.018(7) nm, which will enable us to immerse a lattice of Yb atoms (the system) into a Rb BEC (superfluid reservoir). We have produced Bose-Einstein condensates of 170Yb and 174Yb, two of the five bosonic isotopes of Yb, which also has two fermionic isotopes. Flexible optical trapping of Rb and Yb was achieved with a two-color dipole trap of 532 and 1064 nm, and we observed thermalization in ultracold mixtures of Rb and Yb. Using the Rb-blind optical lattice, we measured very small light shifts of 87Rb BECs near the light shift zero-wavelengths adjacent the 6p electronic states, through a coherent series of lattice pulses. The positions of the zero-wavelengths are sensitive to the electric dipole matrix elements between the 5s and 6p states, and we made the first experimental measurement of their strength. By measuring a light shift, we were not sensitive to excited state branching ratios, and we achieved a precision better than 0.3%.

Asymmetric diffraction by atomic gratings with optical PT symmetry in the Raman-Nath regime

NASA Astrophysics Data System (ADS)

Shui, Tao; Yang, Wen-Xing; Liu, Shaopeng; Li, Ling; Zhu, Zhonghu

2018-03-01

We propose and analyze an efficient scheme for the lopsided Raman-Nath diffraction of one-dimensional (1 D ) and two-dimensional (2 D ) atomic gratings with periodic parity-time (PT )-symmetric refractive index. The atomic grating is constructed by the cold-atomic vapor with two isotopes of rubidium, which is driven by weak probe field and space-dependent control field. Using experimentally achievable parameters, we identify the conditions under which PT -symmetric refractive index allows us to observe the lopsided Raman-Nath diffraction phenomenon and improve the diffraction efficiencies beyond what is achievable in a conventional atomic grating. The nontrivial atomic grating is a superposition of an amplitude grating and a phase grating. It is found that the lopsided Raman-Nath diffraction at the exceptional point (EP) of PT -symmetric grating originates from constructive and destructive interferences between the amplitude and phase gratings. Furthermore, we show that the PT -phase transition from unbroken to broken PT -symmetric regimes can modify the asymmetric distribution of the diffraction spectrum and that the diffraction efficiencies in the non-negative diffraction orders can be significantly enhanced when the atomic grating is pushed into a broken PT -symmetric phase. In addition, we also analyze the influence of the grating thickness on the diffraction spectrum. Our scheme may provide the possibility to design a gain-beam splitter with tunable splitting ratio and other optical components in integrated optics.

Simple, low-noise piezo driver with feed-forward for broad tuning of external cavity diode lasers.

PubMed

Doret, S Charles

2018-02-01

We present an inexpensive, low-noise (<260 μV rms , 0.1 Hz-100 kHz) design for a piezo driver suitable for frequency tuning of external-cavity diode lasers. This simple driver improves upon many commercially available drivers by incorporating circuitry to produce a "feed-forward" signal appropriate for making simultaneous adjustments to the piezo voltage and laser current, enabling dramatic improvements in a mode-hop-free laser frequency tuning range. We present the theory behind our driver's operation, characterize its output noise, and demonstrate its use in absorption spectroscopy on the rubidium D 1 line.

Implications of convection in the Moon and the terrestrial planets

NASA Technical Reports Server (NTRS)

Turcotte, Donald L.

1987-01-01

The early thermal and chemical evolution of the Moon is discussed. The rubidium-strontium, neodymium-samarium, and uranium-thorium-lead systems were studied. The relation of source region heterogeneity to the mixing associated with mantle convection is considered. Work on the application of fractal concepts to planetary geology and geophysics is also discussed. The fractal concept was applied to fragmentation, including the frequency-size distribution of meteorites, asteroids and particulate matter produced by impacts.

3D-printed components for quantum devices.

PubMed

Saint, R; Evans, W; Zhou, Y; Barrett, T; Fromhold, T M; Saleh, E; Maskery, I; Tuck, C; Wildman, R; Oručević, F; Krüger, P

2018-05-30

Recent advances in the preparation, control and measurement of atomic gases have led to new insights into the quantum world and unprecedented metrological sensitivities, e.g. in measuring gravitational forces and magnetic fields. The full potential of applying such capabilities to areas as diverse as biomedical imaging, non-invasive underground mapping, and GPS-free navigation can only be realised with the scalable production of efficient, robust and portable devices. We introduce additive manufacturing as a production technique of quantum device components with unrivalled design freedom and rapid prototyping. This provides a step change in efficiency, compactness and facilitates systems integration. As a demonstrator we present an ultrahigh vacuum compatible ultracold atom source dissipating less than ten milliwatts of electrical power during field generation to produce large samples of cold rubidium gases. This disruptive technology opens the door to drastically improved integrated structures, which will further reduce size and assembly complexity in scalable series manufacture of bespoke portable quantum devices.

Designing Ratchets in Ultra-cold Atoms for the Advanced Undergraduate Laboratory

NASA Astrophysics Data System (ADS)

Hachtel, Andrew; Gillette, Matthew; Clements, Ethan; Zhong, Shan; Ducay, Rey; Bali, Samir

2014-05-01

We propose to perform ratchet experiments in cold Rubidium atoms using state-of-the-art home-built tapered amplifier and imaging systems. Our tapered amplifier system amplifies the output from home-built external cavity tunable diode lasers up to a factor 100 and costs less than 5,000, in contrast to commercial tapered amplifier systems, which cost upward of 20,000. We have developed an imaging system with LabVIEW integration, which allows for approximately 2 millisecond exposures and microsecond control of experimental parameters. Our imaging system also costs less than 5,000 in comparison to commercial options, which cost between 40-50,000. Progress toward implementation of a one-dimensional rocking ratchet is described. We gratefully acknowledge funding from the American Chemical Society Petroleum Research Fund and Miami University. We also acknowledge the Miami University Instrumentation Laboratory for their invaluable contributions.

Solid-state ensemble of highly entangled photon sources at rubidium atomic transitions

NASA Astrophysics Data System (ADS)

Zopf, Michael; Keil, Robert; Chen, Yan; HöFer, Bianca; Zhang, Jiaxiang; Ding, Fei; Schmidt, Oliver G.

Semiconductor InAs/GaAs quantum dots grown by the Stranski-Krastanov method are among the leading candidates for the deterministic generation of polarization entangled photon pairs. Despite remarkable progress in the last twenty years, many challenges still remain for this material, such as the extremely low yield (< 1% quantum dots can emit entangled photons), the low degree of entanglement, and the large wavelength distribution. Here we show that, with an emerging family of GaAs/AlGaAs quantum dots grown by droplet etching and nanohole infilling, it is possible to obtain a large ensemble (close to 100%) of polarization-entangled photon emitters on a wafer without any post-growth tuning. Under pulsed resonant two-photon excitation, all measured quantum dots emit single pairs of entangled photons with ultra-high purity, high degree of entanglement (fidelity up to F=0.91, with a record high concurrence C=0.90), and ultra-narrow wavelength distribution at rubidium transitions. Therefore, a solid-state quantum repeater - among many other key enabling quantum photonic elements - can be practically implemented with this new material. Financially supported by BMBF Q.Com-H (16KIS0106) and the Euro- pean Union Seventh Framework Programme 209 (FP7/2007-2013) under Grant Agreement No. 601126 210 (HANAS).

Ultralong-range Rydberg Molecules: Investigation of a Novel Binding Mechanism

NASA Astrophysics Data System (ADS)

Butscher, Björn; Bendkowsky, Vera; Nipper, Johannes; Balewski, Jonathan; Shaffer, James P.; Löw, Robert; Pfau, Tilman

2010-03-01

For highly excited Rydberg atoms, the scattering of the Rydberg electron from a nearby polarizable ground state atom can generate an attractive mean-field potential which is able to bind the ground state atom to the Rydberg atom within the Rydberg electron wave function at binding energies ranging from a few MHz to hundreds of MHz[1]. We present spectroscopic data on the observation of various bound states including the vibrational ground and excited states of rubidium dimers Rb(5S)-Rb(nS) as well as those of trimer states. Furthermore, we show calculations that reproduce the observed binding energies remarkably well and reveal that some of the excited states are purely bound by quantum reflection at a shape resonance for p-wave scattering [2]. To further characterize the coherent excitation of the molecular states, we performed echo experiments. [0pt] [1] V. Bendkowsky, B. Butscher, J. Nipper, J. P. Shaffer, R. Löw, T. Pfau, Nature 458, 1005 (2009); [2] V. Bendkowsky, B. Butscher, J. Nipper, J. Balewski, J. P. Shaffer, R. Löw, T. Pfau, W. Li, J. Stanojevic, T. Pohl,and J. M. Rost, arXiv:0912.4058 (2009)

Above-threshold scattering about a Feshbach resonance for ultracold atoms in an optical collider.

PubMed

Horvath, Milena S J; Thomas, Ryan; Tiesinga, Eite; Deb, Amita B; Kjærgaard, Niels

2017-09-06

Ultracold atomic gases have realized numerous paradigms of condensed matter physics, where control over interactions has crucially been afforded by tunable Feshbach resonances. So far, the characterization of these Feshbach resonances has almost exclusively relied on experiments in the threshold regime near zero energy. Here, we use a laser-based collider to probe a narrow magnetic Feshbach resonance of rubidium above threshold. By measuring the overall atomic loss from colliding clouds as a function of magnetic field, we track the energy-dependent resonance position. At higher energy, our collider scheme broadens the loss feature, making the identification of the narrow resonance challenging. However, we observe that the collisions give rise to shifts in the center-of-mass positions of outgoing clouds. The shifts cross zero at the resonance and this allows us to accurately determine its location well above threshold. Our inferred resonance positions are in excellent agreement with theory.Studies on energy-dependent scattering of ultracold atoms were previously carried out near zero collision energies. Here, the authors observe a magnetic Feshbach resonance in ultracold Rb collisions for above-threshold energies and their method can also be used to detect higher partial wave resonances.

Quantum teleportation between remote atomic-ensemble quantum memories.

PubMed

Bao, Xiao-Hui; Xu, Xiao-Fan; Li, Che-Ming; Yuan, Zhen-Sheng; Lu, Chao-Yang; Pan, Jian-Wei

2012-12-11

Quantum teleportation and quantum memory are two crucial elements for large-scale quantum networks. With the help of prior distributed entanglement as a "quantum channel," quantum teleportation provides an intriguing means to faithfully transfer quantum states among distant locations without actual transmission of the physical carriers [Bennett CH, et al. (1993) Phys Rev Lett 70(13):1895-1899]. Quantum memory enables controlled storage and retrieval of fast-flying photonic quantum bits with stationary matter systems, which is essential to achieve the scalability required for large-scale quantum networks. Combining these two capabilities, here we realize quantum teleportation between two remote atomic-ensemble quantum memory nodes, each composed of ∼10(8) rubidium atoms and connected by a 150-m optical fiber. The spin wave state of one atomic ensemble is mapped to a propagating photon and subjected to Bell state measurements with another single photon that is entangled with the spin wave state of the other ensemble. Two-photon detection events herald the success of teleportation with an average fidelity of 88(7)%. Besides its fundamental interest as a teleportation between two remote macroscopic objects, our technique may be useful for quantum information transfer between different nodes in quantum networks and distributed quantum computing.

Frequency-comb-assisted precision laser spectroscopy of CHF{sub 3} around 8.6 μm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gambetta, Alessio; Coluccelli, Nicola; Cassinerio, Marco

2015-12-21

We report a high-precision spectroscopic study of room-temperature trifluoromethane around 8.6 μm, using a CW quantum cascade laser phase-locked to a mid-infrared optical frequency comb. This latter is generated by a nonlinear down-conversion process starting from a dual-branch Er:fiber laser and is stabilized against a GPS-disciplined rubidium clock. By tuning the comb repetition frequency, several transitions falling in the υ{sub 5} vibrational band are recorded with a frequency resolution of 20 kHz. Due to the very dense spectra, a special multiple-line fitting code, involving a Voigt profile, is developed for data analysis. The combination of the adopted experimental approach andmore » survey procedure leads to fractional accuracy levels in the determination of line center frequencies, down to 2 × 10{sup −10}. Line intensity factors, pressure broadening, and shifting parameters are also provided.« less

Dressing control of biphoton waveform transitions

NASA Astrophysics Data System (ADS)

Li, Xinghua; Zhang, Dan; Zhang, Da; Hao, Ling; Chen, Haixia; Wang, Zhiguo; Zhang, Yanpeng

2018-05-01

We experimentally realize and theoretically analyze narrow-band biphotons generated in a hot rubidium vapor cell by four-wave-mixing processing. A dressing laser beam is used to alternate both linear and nonlinear susceptibilities of the vapor, thereby modifying the biphoton's temporal correlation function. Most notably, the correlation time is increased from 6 to 165 ns. The biphoton shape is also shown to change as a result of the coupled-states dressing. We observed Rabi oscillations and optical precursors in hot atomic vapor cells. We also theoretically simulated biphoton correlation times as influenced by dressing-laser detuning and power, the results of which are consistent with our experiments.

Crystal structure of langbeinite-related Rb0.743K0.845Co0.293Ti1.707(PO4)3.

PubMed

Strutynska, Nataliia Yu; Bondarenko, Marina A; Ogorodnyk, Ivan V; Baumer, Vyacheslav N; Slobodyanik, Nikolay S

2015-03-01

Potassium rubidium cobalt(II)/titanium(IV) tris-(orthophosphate), Rb0.743K0.845Co0.293Ti1.707(PO4)3, has been obtained using a high-temperature crystallization method. The obtained compound has a langbeinite-type structure. The three-dimensional framework is built up from mixed-occupied (Co/Ti(IV))O6 octa-hedra (point group symmetry .3.) and PO4 tetra-hedra. The K(+) and Rb(+) cations are statistically distributed over two distinct sites (both with site symmetry .3.) in the large cavities of the framework. They are surrounded by 12 O atoms.

Cesium and Rubidium Frequency Standards Status and Performance on the GPS Program

NASA Technical Reports Server (NTRS)

VanMelle, M. J.

1996-01-01

This paper is an update of the on-orbit operational performance of the frequency standards on the last Block 1 Navstar satellite (GPS-10), the complete Block 2 Navstar satellites (GPS-13 to 21) and the Block 2A Navstar (GPS-22 to 40) satellites. Since the status of the GPS constellation is now at full operational capability (FOC), a minimum of twenty-four satellites are in position with all the necessary tests successfully completed. The evolution of frequency standards on board the GPS vehicles will be presented with corresponding results. Various methods and techniques will be presented to show on-orbit life time, down time, state of health telemetry, on-orbit trending and characterization of all the frequency standards. Other topics such as reliability, stability, clock quirks and idiosyncrasies of each vehicle will be covered.

Bioavailability of Lead in Small Arms Range Soils

DTIC Science & Technology

2007-09-01

minerals, and may also exist inside particles of inert matrix such as rock or slag of variable size, shape, and association; these chemical and...Abbreviations: Fe=iron, Pb=lead, Cu=copper, Ti=titanium, Zn= zinc , Sb=antimony, Rb=rubidium, Zr=zirconium, As=arsenic. Values are mean of three...20 30 40 50 60 70 80 FeOOH Cerussite Organic Phosphate PbMO PbAsO MnOOH Anglesite PbOOH PbCl4 Slag FeSO4 PbO Frequency of Occurrence Relative Pb

Rubidium-87 gas cell studies, phase 2

NASA Technical Reports Server (NTRS)

Vanier, J.

1973-01-01

A description is given of the development of a compact rubidium-87 maser. Data cover the electronic control system for the maser itself and a superhetrodyne receiver capable of locking a crystal oscillator to the maser signal.

Study and Optimization of CPT Resonance Parameters in 87 Rb/Ar/Ne Microcells Aimed for Application in Metrology

NASA Astrophysics Data System (ADS)

Masian, Y.; Sivak, A.; Sevostianov, D.; Vassiliev, V.; Velichansky, V.

The paper shows the presents results of studies of small-size rubidium cells with argon and neon buffer gases, produced by a patent pended technique of laser welding [Fishman et al. (2014)]. Cells were designed for miniature frequency standard. Temperature dependence of the frequency of the coherent population trapping (CPT) resonance was measured and used to optimize the ratio of partial pressures of buffer gases. The influence of duration and regime of annealing on the CPT-resonance frequency drift was investigated. The parameters of the FM modulation of laser current for two cases which correspond to the highest amplitude of CPT resonance and to the smallest light shifts of the resonance frequency were determined. The temperature dependences of the CPT resonance frequency were found to be surprisingly different in the two cases. A non-linear dependence of CPT resonance frequency on the temperature of the cell with the two extremes was revealed for one of these cases.

Excitation of higher lying energy states in a rubidium DPAL

NASA Astrophysics Data System (ADS)

Wallerstein, A. J.; Perram, Glen; Rice, Christopher A.

2018-02-01

The spontaneous emission in a cw rubidium diode dumped alkali laser (DPAL) system was analyzed. The fluorescence from higher lying states decreases with additional buffer gas. The intermediate states (7S, 6P, 5D) decay more slowly with buffer gas and scale super-linearly with alkali density. A detailed kinetic model has been constructed, where the dominant mechanisms are energy pooling and single photon ionization. It also includes pumping into the non-Lorentzian wings of absorption profiles, fine structure mixing, collisional de-excitation, and Penning ionization. Effects of ionization in a high powered CW rubidium DPAL were assessed.

Disciplined rubidium oscillator with GPS selective availability

NASA Technical Reports Server (NTRS)

Dewey, Wayne P.

1993-01-01

A U.S. Department of Defense decision for continuous implementation of GPS Selective Availability (S/A) has made it necessary to modify Rubidium oscillator disciplining methods. One such method for reducing the effects of S/A on the oscillator disciplining process was developed which achieves results approaching pre-S/A GPS. The Satellite Hopping algorithm used in minimizing the effects of S/A on the oscillator disciplining process is described, and the results of using this process to those obtained prior to the implementation of S/A are compared. Test results are from a TrueTime Rubidium based Model GPS-DC timing receiver.

The antipsychotic drug loxapine is an opener of the sodium-activated potassium channel slack (Slo2.2).

PubMed

Biton, B; Sethuramanujam, S; Picchione, Kelly E; Bhattacharjee, A; Khessibi, N; Chesney, F; Lanneau, C; Curet, O; Avenet, P

2012-03-01

Sodium-activated potassium (K(Na)) channels have been suggested to set the resting potential, to modulate slow after-hyperpolarizations, and to control bursting behavior or spike frequency adaptation (Trends Neurosci 28:422-428, 2005). One of the genes that encodes K(Na) channels is called Slack (Kcnt1, Slo2.2). Studies found that Slack channels were highly expressed in nociceptive dorsal root ganglion neurons and modulated their firing frequency (J Neurosci 30:14165-14172, 2010). Therefore, Slack channel openers are of significant interest as putative analgesic drugs. We screened the library of pharmacologically active compounds with recombinant human Slack channels expressed in Chinese hamster ovary cells, by using rubidium efflux measurements with atomic absorption spectrometry. Riluzole at 500 μM was used as a reference agonist. The antipsychotic drug loxapine and the anthelmintic drug niclosamide were both found to activate Slack channels, which was confirmed by using manual patch-clamp analyses (EC(50) = 4.4 μM and EC(50) = 2.9 μM, respectively). Psychotropic drugs structurally related to loxapine were also evaluated in patch-clamp experiments, but none was found to be as active as loxapine. Loxapine properties were confirmed at the single-channel level with recombinant rat Slack channels. In dorsal root ganglion neurons, loxapine was found to behave as an opener of native K(Na) channels and to increase the rheobase of action potential. This study identifies new K(Na) channel pharmacological tools, which will be useful for further Slack channel investigations.

Expansion of an ultracold Rydberg plasma

NASA Astrophysics Data System (ADS)

Forest, Gabriel T.; Li, Yin; Ward, Edwin D.; Goodsell, Anne L.; Tate, Duncan A.

2018-04-01

We report a systematic experimental and numerical study of the expansion of ultracold Rydberg plasmas. Specifically, we have measured the asymptotic expansion velocities, v0, of ultracold neutral plasmas (UNPs) which evolve from cold, dense samples of Rydberg rubidium atoms using ion time-of-flight spectroscopy. From this, we have obtained values for the effective initial plasma electron temperature, Te ,0=mionv02/kB (where mion is the Rb+ ion mass), as a function of the original Rydberg atom density and binding energy, Eb ,i. We have also simulated numerically the interaction of UNPs with a large reservoir of Rydberg atoms to obtain data to compare with our experimental results. We find that for Rydberg atom densities in the range 107-109 cm-3, for states with principal quantum number n >40 , Te ,0 is insensitive to the initial ionization mechanism which seeds the plasma. In addition, the quantity kBTe ,0 is strongly correlated with the fraction of atoms which ionize, and is in the range 0.6 ×| Eb ,i|≲ kBTe ,0≲2.5 ×|Eb ,i| . On the other hand, plasmas from Rydberg samples with n ≲40 evolve with no significant additional ionization of the remaining atoms once a threshold number of ions has been established. The dominant interaction between the plasma electrons and the Rydberg atoms is one in which the atoms are deexcited, a heating process for electrons that competes with adiabatic cooling to establish an equilibrium where Te ,0 is determined by their Coulomb coupling parameter, Γe˜0.01 .

Antibunched emission of photon pairs via quantum Zeno blockade.

PubMed

Huang, Yu-Ping; Kumar, Prem

2012-01-20

We propose a new methodology, namely, the "quantum Zeno blockade," for managing light scattering at a few-photon level in general nonlinear-optical media, such as crystals, fibers, silicon microrings, and atomic vapors. Using this tool, antibunched emission of photon pairs can be achieved, leading to potent quantum-optics applications such as deterministic entanglement generation without the need for heralding. In a practical implementation using an on-chip toroidal microcavity immersed in rubidium vapor, we estimate that high-fidelity entangled photons can be produced on-demand at MHz rates or higher, corresponding to an improvement of ≳10(7) times from the state-of-the-art. © 2012 American Physical Society

Crystal structure of langbeinite-related Rb0.743K0.845Co0.293Ti1.707(PO4)3

PubMed Central

Strutynska, Nataliia Yu.; Bondarenko, Marina A.; Ogorodnyk, Ivan V.; Baumer, Vyacheslav N.; Slobodyanik, Nikolay S.

2015-01-01

Potassium rubidium cobalt(II)/titanium(IV) tris­(orthophosphate), Rb0.743K0.845Co0.293Ti1.707(PO4)3, has been obtained using a high-temperature crystallization method. The obtained compound has a langbeinite-type structure. The three-dimensional framework is built up from mixed-occupied (Co/TiIV)O6 octa­hedra (point group symmetry .3.) and PO4 tetra­hedra. The K+ and Rb+ cations are statistically distributed over two distinct sites (both with site symmetry .3.) in the large cavities of the framework. They are surrounded by 12 O atoms. PMID:25844179

Quantum teleportation between remote atomic-ensemble quantum memories

PubMed Central

Bao, Xiao-Hui; Xu, Xiao-Fan; Li, Che-Ming; Yuan, Zhen-Sheng; Lu, Chao-Yang; Pan, Jian-Wei

2012-01-01

Quantum teleportation and quantum memory are two crucial elements for large-scale quantum networks. With the help of prior distributed entanglement as a “quantum channel,” quantum teleportation provides an intriguing means to faithfully transfer quantum states among distant locations without actual transmission of the physical carriers [Bennett CH, et al. (1993) Phys Rev Lett 70(13):1895–1899]. Quantum memory enables controlled storage and retrieval of fast-flying photonic quantum bits with stationary matter systems, which is essential to achieve the scalability required for large-scale quantum networks. Combining these two capabilities, here we realize quantum teleportation between two remote atomic-ensemble quantum memory nodes, each composed of ∼108 rubidium atoms and connected by a 150-m optical fiber. The spin wave state of one atomic ensemble is mapped to a propagating photon and subjected to Bell state measurements with another single photon that is entangled with the spin wave state of the other ensemble. Two-photon detection events herald the success of teleportation with an average fidelity of 88(7)%. Besides its fundamental interest as a teleportation between two remote macroscopic objects, our technique may be useful for quantum information transfer between different nodes in quantum networks and distributed quantum computing. PMID:23144222

Probing the structural and electronic properties of cationic rubidium-gold clusters: [AunRb]+ (n = 1-10)

NASA Astrophysics Data System (ADS)

Zhao, Ya-Ru; Zhang, Hai-Rong; Qian, Yu; Duan, Xu-Chao; Hu, Yan-Fei

2016-03-01

Density functional theory has been applied to study the geometric structures, relative stabilities, and electronic properties of cationic [AunRb]+ and Aun + 1+ (n = 1-10) clusters. For the lowest energy structures of [AunRb]+ clusters, the planar to three-dimensional transformation is found to occur at cluster size n = 4 and the Rb atoms prefer being located at the most highly coordinated position. The trends of the averaged atomic binding energies, fragmentation energies, second-order difference of energies, and energy gaps show pronounced even-odd alternations. It indicated that the clusters containing odd number of atoms maintain greater stability than the clusters in the vicinity. In particular, the [Au6Rb]+ clusters are the most stable isomer for [AunRb]+ clusters in the region of n = 1-10. The charges in [AunRb]+ clusters transfer from the Rb atoms to Aun host. Density of states revealed that the Au-5d, Au-5p, and Rb-4p orbitals hardly participated in bonding. In addition, it is found that the most favourable channel of the [AunRb]+ clusters is Rb+ cation ejection. The electronic localisation function (ELF) analysis of the [AunRb]+ clusters shown that strong interactions are not revealed in this study.

Provisional Peer-Reviewed Toxicity Values for Rubidium Compounds (Rubidium)

EPA Science Inventory

Provisional Peer-Reviewed Toxicity Values (PPRTV) assessments are developed for use by the Agency’s Office of Land and Emergency Management (OLEM) to support informed decisions in the Superfund program and at hazardous waste sites when a values is not available in the Integrated ...

Analysis of decoherence mechanisms in a single-atom quantum memory

NASA Astrophysics Data System (ADS)

Koerber, Matthias; Langenfeld, Stefan; Morin, Olivier; Neuzner, Andreas; Ritter, Stephan; Rempe, Gerhard

2017-04-01

While photons are ideal for the transmission of quantum information, they require dedicated memories for long-term storage. The challenge for such a photonic quantum memory is the combination of an efficient light-matter interface with a low-decoherence encoding. To increase the time before the quantum information is lost, a thorough analysis of the relevant decoherence mechanisms is indispensable. Our optical quantum memory consists of a single rubidium atom trapped in a two dimensional optical lattice in a high-finesse Fabry-Perot-type optical resonator. The qubit is initially stored in a superposition of Zeeman states, making magnetic field fluctuations the dominant source of decoherence. The impact to this type of noise is greatly reduced by transferring the qubit into a subspace less susceptible to magnetic field fluctuations. In this configuration, the achievable coherence times are no longer limited by those fluctuations, but decoherence mechanisms induced by the trapping beams pose a new limit. We will discuss the origin and magnitude of the relevant effects and strategies for possible resolutions.

Spectroscopic and theoretical investigations of alkali metal linoleates and oleinates

NASA Astrophysics Data System (ADS)

Świsłocka, Renata; Regulska, Ewa; Jarońko, Paweł; Lewandowski, Włodzimierz

2017-11-01

The influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of the linoleic (cis-9,cis-12-octadecadienoic) and oleic (cis-9-octadecenoic) acids was investigated. The complementary analytical methods: vibrational (IR, Raman) and electronic (UV) molecular absorption spectroscopy as well as DFT quantum mechanical calculations (charge distribution, angles between bonds, bond lengths, theoretical IR and NMR spectra) were carried out. The regular shifts of bands connected with carboxylate anion in the spectra of studied salts were observed. Some bonds and angles reduced or elongated in the series: acid→Li→Na→K linoleates/oleinates. The highest changes were noted for bond lengths and angles concerning COO- ion. The electronic charge distribution in studied molecules was also discussed. Total atomic charges of carboxylate anion decrease as a result of the replacement of hydrogen atom with alkali metal cation. The increasing values of dipole moment and decreasing values of total energy in the order: linoleic/oleic acid→lithium→sodium→potassium linoleates/oleinates indicate an increase in stability of the compounds.

Atomic magnetometer for human magnetoencephalograpy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwindt, Peter; Johnson, Cort N.

2010-12-01

We have developed a high sensitivity (<5 fTesla/{radical}Hz), fiber-optically coupled magnetometer to detect magnetic fields produced by the human brain. This is the first demonstration of a noncryogenic sensor that could replace cryogenic superconducting quantum interference device (SQUID) magnetometers in magnetoencephalography (MEG) and is an important advance in realizing cost-effective MEG. Within the sensor, a rubidium vapor is optically pumped with 795 laser light while field-induced optical rotations are measured with 780 nm laser light. Both beams share a single optical axis to maximize simplicity and compactness. In collaboration with neuroscientists at The Mind Research Network in Albuquerque, NM, themore » evoked responses resulting from median nerve and auditory stimulation were recorded with the atomic magnetometer and a commercial SQUID-based MEG system with signals comparing favorably. Multi-sensor operation has been demonstrated with two AMs placed on opposite sides of the head. Straightforward miniaturization would enable high-density sensor arrays for whole-head magnetoencephalography.« less

μ-Hexa-thio-metadiphosphato-bis-[(1,4,7,10,13,16-hexa-oxa-cyclo-octa-decane-κ(6) O)rubidium] aceto-nitrile disolvate.

PubMed

Gjikaj, Mimoza; Pook, Niels-Patrick; Qarri, Flora

2013-12-01

The asymmetric unit of the title compound, [Rb2(P2S6)(C12H24O6)2]·2CH3CN, contains one half of an [Rb(18-crown-6)2]2[P2S6] unit and one aceto-nitrile solvent mol-ecule. The [Rb(18-crown-6)]2[P2S6] unit is completed by inversion symmetry. Its Rb(+) ion is situated near the centre of the macrocyclic cavity, but is displaced by 0.8972 (1) Å from the O atoms of the crown in the direction of the [P2S6](2-) moiety. The overall coordination number of the cation is eight, defined by the six crown ether O atoms and by two terminal S atoms of the [P2S6](2-) anion. The hexa-thio-metadiphosphate anion is built up from two tetra-hedral PS4 units joined together by a common edge. The crystal structure is characterized by alternating layers of [Rb(18-crown-6)]2[P2S6] and aceto-nitrile solvent mol-ecules stacked along [010].

Ultra-low power, Zeno effect based optical modulation in a degenerate V-system with a tapered nano fiber in atomic vapor.

PubMed

Salit, K; Salit, M; Krishnamurthy, Subramanian; Wang, Y; Kumar, P; Shahriar, M S

2011-11-07

We demonstrate an ultra-low light level optical modulator using a tapered nano fiber embedded in a hot rubidium vapor. The control and signal beams are co-propagating but orthogonally polarized, leading to a degenerate V-system involving coherent superpositions of Zeeman sublevels. The modulation is due primarily to the quantum Zeno effect for the signal beam induced by the control beam. For a control power of 40 nW and a signal power of 100 pW, we observe near 100% modulation. The ultra-low power level needed for the modulation is due to a combination of the Zeno effect and the extreme field localization in the evanescent field around the taper.

Photon statistics and polarization correlations at telecommunications wavelengths from a warm atomic ensemble.

PubMed

Willis, R T; Becerra, F E; Orozco, L A; Rolston, S L

2011-07-18

We present measurements of the polarization correlation and photon statistics of photon pairs that emerge from a laser-pumped warm rubidium vapor cell. The photon pairs occur at 780 nm and 1367 nm and are polarization entangled. We measure the autocorrelation of each of the generated fields as well as the cross-correlation function, and observe a strong violation of the two-beam Cauchy-Schwartz inequality. We evaluate the performance of the system as source of heralded single photons at a telecommunication wavelength. We measure the heralded autocorrelation and see that coincidences are suppressed by a factor of ≈ 20 from a Poissonian source at a generation rate of 1500 s(-1), a heralding efficiency of 10%, and a narrow spectral width.

Complex Dipolar Matter

DTIC Science & Technology

2014-11-10

opportunities for advanced material development and quantum simulators. These molecules include (1) the already quantum degenerate bi- alkali singlet sigma...case potassium-rubidium (KRb) and related molecules; (2) opto-electrically trapped symmetric top molecules soon to reach quantum degeneracy and...rubidium; (C) a correction of phase diagrams for dipolar gases necessary to understand experimental measurements and build accurate quantum simulators

Compact, Highly Stable Ion Atomic Clock

NASA Technical Reports Server (NTRS)

Prestage, John

2008-01-01

A mercury-ion clock now at the breadboard stage of development (see figure) has a stability comparable to that of a hydrogen-maser clock: In tests, the clock exhibited an Allan deviation of between 2 x 10(exp -13) and 3 x 10(exp -13) at a measurement time of 1 second, averaging to about 10(exp -15) at 1 day. However, the clock occupies a volume of only about 2 liters . about a hundredth of the volume of a hydrogen-maser clock. The ion-handling parts of the apparatus are housed in a sealed vacuum tube, wherein only a getter pump is used to maintain the vacuum. Hence, this apparatus is a prototype of a generation of small, potentially portable high-precision clocks for diverse ground- and space-based navigation and radio science applications. Furthermore, this new ion-clock technology is about 100 times more stable and precise than the rubidium atomic clocks currently in use in the NAV STAR GPS Earth-orbiting satellites. In this clock, mercury ions are shuttled between a quadrupole and a 16-pole linear radio-frequency trap. In the quadrupole trap, the ions are tightly confined and optical state selection from a Hg-202 radio-frequency-discharge ultraviolet lamp is carried out. In the 16-pole trap, the ions are more loosely confined and atomic transitions resonant at frequency of about 40.507 GHz are interrogated by use of a microwave beam at that frequency. The trapping of ions effectively eliminates the frequency pulling caused by wall collisions inherent to gas-cell clocks. The shuttling of the ions between the two traps enables separation of the state-selection process from the clock microwave- resonance process, so that each of these processes can be optimized independently of the other. The basic ion-shuttling, two-trap scheme as described thus far is not new: it has been the basis of designs of prior larger clocks. The novelty of the present development lies in major redesigns of its physics package (the ion traps and the vacuum and optical subsystems) to effect the desired reduction of size to a volume of no more than a couple of liters. The redesign effort has included selection of materials for the vacuum tube, ion trap, and ultraviolet windows that withstand bakeout at a temperature of approx.450 C in preparation for sealing the tube to contain the vacuum. This part of the redesign effort follows the approach taken in the development of such other vacuum-tube electronic components as flight traveling- wave-tube amplifiers having operational and shelf lives as long as 15 years. The redesign effort has also included a thorough study of residual-gas-induced shifts of the ion-clock frequency and a study of alternative gases as candidates for use as a buffer gas within the sealed tube. It has been found that neon is more suitable than is helium, which has been traditionally used for this purpose, in that the pressure-induced frequency pulling by neon is between a third and a half of that of helium. In addition, because neon diffuses through solids much more slowly than does helium, the loss of neon by diffusion over the operational lifetime is expected to be negligible.

Two-Photon Excitation of Launched Cold Atoms in Flight

NASA Astrophysics Data System (ADS)

Goodsell, Anne; Gonzalez, Rene; Alejandro, Eduardo; Erwin, Emma

2017-04-01

We demonstrate two-photon bi-chromatic excitation of cold rubidium atoms in flight, using the pathway 5S1 / 2 -> 5P3 / 2 -> 5D5 / 2 with two resonant photons. In our experiment, atoms are laser-cooled in a magneto-optical trap and launched upward in discrete clouds with a controllable vertical speed of 7.1 +/-0.6 m/s and a velocity spread that is less than 10% of the launch speed. Outside the cooling beams, as high as 14 mm above the original center of the trap, the launched cold atoms are illuminated simultaneously by spatially-localized horizontal excitation beams at 780 nm (5S1 / 2 -> 5P3 / 2) and 776 nm (5P3 / 2 -> 5D5 / 2). We monitor transmission of the 780-nm beam over a range of intensities of 780-nm and 776-nm light. As the center of the moving cloud passes the excitation beams, we observe as much as 97.9 +/-1.2% transmission when the rate of two-photon absorption is high and the 5S1 / 2 and 5P3 / 2 states are depopulated, compared to 87.6 +/-0.9% transmission if only the 780-nm beam is present. This demonstrates two-photon excitation of a launched cold-atom source with controllable launch velocity and narrow velocity spread, as a foundation for three-photon excitation to Rydberg states. Research supported by Middlebury College Bicentennial Fund, Palen Fund, and Gladstone Award.

The 26th Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting

NASA Technical Reports Server (NTRS)

Sydnor, Richard (Editor)

1995-01-01

This document is a compilation of technical papers presented at the 26th Annual PTTI Applications and Planning Meeting. Papers are in the following categories: (1) Recent developments in rubidium, cesium, and hydrogen-based frequency standards, and in cryogenic and trapped-ion technology; (2) International and transnational applications of Precise Time and Time Interval technology with emphasis on satellite laser tracking, GLONASS timing, intercomparison of national time scales and international telecommunications; (3) Applications of Precise Time and Time Interval technology to the telecommunications, power distribution, platform positioning, and geophysical survey industries; (4) Applications of PTTI technology to evolving military communications and navigation systems; and (5) Dissemination of precise time and frequency by means of GPS, GLONASS, MILSTAR, LORAN, and synchronous communications satellites.

Solvothermal syntheses and characterization of three new silver(I)/copper(I)-thioarsenates based on As{sup 2+}/As{sup 3+} ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, Hua-Gang, E-mail: hgyao@gdpu.edu.cn; Guangdong Cosmetics Engineering & Technology Research Center, Zhongshan 528458; Tang, Cheng-Fei

2017-02-15

Three new silver(I)/copper(I)-thioarsenates KAgAs{sup II}S{sub 2} (1), RbCu{sub 2}As{sup III}S{sub 3} (2) and RbCu{sub 4}As{sup III}S{sub 4} (3) have been solvothermally synthesized and structurally characterized. 1 exhibits a two-dimensional anionic network built up by As−As bond connecting the left- and right-handed helical [AgS{sub 2}]{sup 4−} chains, and represents the first examples of thioarsenates(II). The structure of 2 consists of two kinds of helical [Cu{sub 2}S{sub 3}]{sup 4–} chains linked by the arsenic atoms to form double layers with rubidium ions between the layers. Compound 3 is built up of infinite [Cu{sub 2}S{sub 2}]{sup 2–} chain and layered [Cu{sub 6}As{sub 2}S{submore » 6}] linked to form a three-dimensional anionic framework, [Cu{sub 4}AsS{sub 4}]{sup –}, and containing channels in which the rubidium cations reside. The optical properties of 1–3 have been investigated by UV–vis spectroscopy. - Graphical abstract: Three new silver(I)/copper(I)-thioarsenates have been solvothermally synthesized and structurally characterized. 1 represents the first examples of thioarsenates(II) while compounds 2 and 3 possess noncondensed pyramidal AsS{sub 3}{sup 3–} unit.« less

Single frequency stable VCSEL as a compact source for interferometry and vibrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dudzik, Grzegorz; Rzepka, Janusz

2010-05-28

Developing an innovative PS-DAVLL (Polarization Switching DAVLL) method of frequency stabilization, which used a ferroelectric liquid crystal cell as quarter wave plate, rubidium cell and developed ultra-stable current source, allowed to obtain a frequency stability of 10{sup -9}(frequency reproducibility of 1,2centre dot10{sup -8}) and reductions in external dimensions of laser source. The total power consumption is only 1,5 Watt. Because stabilization method used in the frequency standard is insensitive to vibration, the semiconductor laser interferometer was built for measuring range over one meter, which can also be used in industry for the accurate measurement of displacements with an accuracy ofmore » 1[mum/m]. Measurements of the VCSEL laser parameters are important from the standpoint of its use in laser interferometry or vibrometry, like narrow emission line DELTAnu{sub FWHM} = 70[MHz] equivalent of this laser type and stability of linear polarization of VCSEL laser. The undoubted advantage of the constructed laser source is the lack of mode-hopping effect during continuous work of VCSEL.« less

Rubidium-traced white-light etalon calibrator for radial velocity measurements at the cm s-1 level

NASA Astrophysics Data System (ADS)

Stürmer, Julian; Seifahrt, Andreas; Schwab, Christian; Bean, Jacob L.

2017-04-01

We report on the construction and testing of a vacuum-gap Fabry-Pérot etalon calibrator for high precision radial velocity spectrographs. Our etalon is traced against a rubidium frequency standard to provide a cost effective, yet ultra precise wavelength reference. We describe here a turn-key system working at 500 to 900 nm, ready to be installed at any current and next-generation radial velocity spectrograph that requires calibration over a wide spectral bandpass. Where appropriate, we have used off-the-shelf, commercial components with demonstrated long-term performance to accelerate the development timescale of this instrument. Our system combines for the first time the advantages of passively stabilized etalons for optical and near-infrared wavelengths with the laser-locking technique demonstrated for single-mode fiber etalons. We realize uncertainties in the position of one etalon line at the 10 cm s-1 level in individual measurements taken at 4 Hz. When binning the data over 10 s, we are able to trace the etalon line with a precision of better than 3 cm s-1. We present data obtained during a week of continuous operation where we detect (and correct for) the predicted, but previously unobserved shrinking of the etalon Zerodur spacer corresponding to a shift of 13 cm s-1 per day.

X-ray spectrographic determination of cesium and rubidium

USGS Publications Warehouse

Axelrod, J.M.; Adler, I.

1957-01-01

An x-ray spectrographic method for the determination of rubidium and cesium was developed, using the internal-standard method and a four-channel flat-crystal spectrograph. The sensitivity is within 0.1% for cesia and 0.02% for rubidia; the precision is within 10% of the amount present. Results agree well with those obtained by flame photometry and by radio-activation.

Scaling of an Optically Pumped Mid-Infrared Rubidium Laser

DTIC Science & Technology

2015-03-26

v AFIT-ENP-MS-15-M-104 Abstract An optically pumped mid-infrared rubidium (Rb) pulsed laser has been demonstrated in a heat pipe ... Heat Pipe Assembly ........................................................................................12 Figure 3.3. Rb Number Density vs. Heat ...the first experiments that used a heat pipe as the gain cell. This experiment would influence the work of Sharma (Sharma, 1981:210). 9 Krupke

μ-Hexa­thio­metadiphosphato-bis­[(1,4,7,10,13,16-hexa­oxa­cyclo­octa­decane-κ6 O)rubidium] aceto­nitrile disolvate

PubMed Central

Gjikaj, Mimoza; Pook, Niels-Patrick; Qarri, Flora

2013-01-01

The asymmetric unit of the title compound, [Rb2(P2S6)(C12H24O6)2]·2CH3CN, contains one half of an [Rb(18-crown-6)2]2[P2S6] unit and one aceto­nitrile solvent mol­ecule. The [Rb(18-crown-6)]2[P2S6] unit is completed by inversion symmetry. Its Rb+ ion is situated near the centre of the macrocyclic cavity, but is displaced by 0.8972 (1) Å from the O atoms of the crown in the direction of the [P2S6]2− moiety. The overall coordination number of the cation is eight, defined by the six crown ether O atoms and by two terminal S atoms of the [P2S6]2− anion. The hexa­thio­metadiphosphate anion is built up from two tetra­hedral PS4 units joined together by a common edge. The crystal structure is characterized by alternating layers of [Rb(18-crown-6)]2[P2S6] and aceto­nitrile solvent mol­ecules stacked along [010]. PMID:24860286

Rubidium Cloud Size in a Magneto-Optical Trap

NASA Astrophysics Data System (ADS)

Chatwin-Davies, A.; Kong, T.; Behr, J. A.; Gorelov, A.; Pearson, M.

2008-05-01

Preparations for a search for exotic 20 - 556 keV-mass particles emitted during the nuclear 2-body decay of ^86Rb confined in a magneto-optical trap (MOT) are underway at TRIUMF. Such emissions would correspond to a peak in the recoil momentum distribution at a momentum lower than that caused by 556 keV γ emission. The stable isotope ^85Rb is being used to optimize the experimental apparatus since its atomic hyperfine splitting is similar to that of ^86Rb, producing similar laser cooling properties. The size of the cloud of trapped atoms directly affects the achievable momentum resolution of the recoil and must hence be minimized. A Doppler-limited model for cloud size ignoring cooling beyond that generated by the photon scattering force is presented and compared with experimental data. Analysis suggested reducing the intensity and red-detuning from resonance of the trapping light from optimal values for atom collection. We also better balanced the power in the trapping beams. Recent data in disagreement with a Doppler-limited theory indicate sub-Doppler cooling mechanisms (J. Dalibard and C. Cohen-Tannoudji, J. Opt. Soc. Am. B 6, 2023 (1989)) are now at work. A cloud full width at half-maximum of less than 0.25 mm has since been achieved.

Magnetoencephalography with a Cs-based high-sensitivity compact atomic magnetometer

NASA Astrophysics Data System (ADS)

Sheng, Jingwei; Wan, Shuangai; Sun, Yifan; Dou, Rongshe; Guo, Yuhao; Wei, Kequan; He, Kaiyan; Qin, Jie; Gao, Jia-Hong

2017-09-01

In recent years, substantial progress has been made in developing a new generation of magnetoencephalography (MEG) with a spin-exchange relaxation free (SERF)-based atomic magnetometer (AM). An AM employs alkali atoms to detect weak magnetic fields. A compact AM array with high sensitivity is crucial to the design; however, most proposed compact AMs are potassium (K)- or rubidium (Rb)-based with single beam configurations. In the present study, a pump-probe two beam configuration with a Cesium (Cs)-based AM (Cs-AM) is introduced to detect human neuronal magnetic fields. The length of the vapor cell is 4 mm, which can fully satisfy the need of designing a compact sensor array. Compared with state-of-the-art compact AMs, our new Cs-AM has two advantages. First, it can be operated in a SERF regime, requiring much lower heating temperature, which benefits the sensor with a closer distance to scalp due to ease of thermal insulation and less electric heating noise interference. Second, the two-beam configuration in the design can achieve higher sensitivity. It is free of magnetic modulation, which is necessary in one-beam AMs; however, such modulation may cause other interference in multi-channel circumstances. In the frequency band between 10 Hz and 30 Hz, the noise level of the proposed Cs-AM is approximately 10 f T/Hz1/2, which is comparable with state-of-the-art K- or Rb-based compact AMs. The performance of the Cs-AM was verified by measuring human auditory evoked fields (AEFs) in reference to commercial superconducting quantum interference device (SQUID) channels. By using a Cs-AM, we observed a clear peak in AEFs around 100 ms (M100) with a much larger amplitude compared with that of a SQUID, and the temporal profiles of the two devices were in good agreement. The results indicate the possibility of using the compact Cs-AM for MEG recordings, and the current Cs-AM has the potential to be designed for multi-sensor arrays and gradiometers for future neuroscience studies.

Quantum dynamics of a two-state system induced by a chirped zero-area pulse

NASA Astrophysics Data System (ADS)

Lee, Han-gyeol; Song, Yunheung; Kim, Hyosub; Jo, Hanlae; Ahn, Jaewook

2016-02-01

It is well known that area pulses make Rabi oscillation and chirped pulses in the adiabatic interaction regime induce complete population inversion of a two-state system. Here we show that chirped zero-area pulses could engineer an interplay between the adiabatic evolution and Rabi-like rotations. In a proof-of-principle experiment utilizing spectral chirping of femtosecond laser pulses with a resonant spectral hole, we demonstrate that the chirped zero-area pulses could induce, for example, complete population inversion and return of the cold rubidium atom two-state system. Experimental result agrees well with the theoretically considered overall dynamics, which could be approximately modeled to a Ramsey-like three-pulse interaction, where the x and z rotations are driven by the hole and the main pulse, respectively.

Enhanced sensitivity of a passive optical cavity by an intracavity dispersive medium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, David D.; Department of Physics, University of Alabama in Huntsville, Huntsville, Alabama 35899; Myneni, Krishna

2009-07-15

The pushing of the modes of a Fabry-Perot cavity by an intracavity rubidium cell is measured. The scale factor of the modes is increased by the anomalous dispersion and is inversely proportional to the sum of the effective group index and an additional cavity delay factor that arises from the variation of the Rb absorption over a free spectral range. This additional positive feedback further increases the effect of the anomalous dispersion and goes to zero at the lasing threshold. The mode width does not grow as fast as the scale factor as the intracavity absorption is increased resulting inmore » enhanced measurement sensitivities. For absorptions larger than the scale factor pole, the atom-cavity response is multivalued and mode splitting occurs.« less

Optical nanofiber temperature monitoring via double heterodyne detection

NASA Astrophysics Data System (ADS)

Anderson, P.; Jalnapurkar, S.; Moiseev, E. S.; Chang, D.; Barclay, P. E.; Lezama, A.; Lvovsky, A. I.

2018-05-01

Tapered optical fibers (nanofibers) whose diameters are smaller than the optical wavelength are very fragile and can be easily destroyed if excessively heated by energy dissipated from the transmitted light. We present a technique for monitoring the nanofiber temperature using two-stage heterodyne detection. The phase of the heterodyne output signal is determined by that of the transmitted optical field, which, in turn, depends on the temperature through the refractive index. From the phase data, by numerically solving the heat exchange equations, the temperature distribution along the nanofiber is determined. The technique is applied to the controlled heating of the nanofiber by a laser in order to remove rubidium atoms adsorbed on its surface that substantially degrade its transmission. Almost 90% of the nanofiber's original transmission is recovered.

27th Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting

NASA Technical Reports Server (NTRS)

Sydnor, Richard L. (Editor)

1996-01-01

This document is a compilation of technical papers presented at the 27th Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting, held November 29 - December 1, 1995 at San Diego, CA. Papers are in the following categories: Recent developments in rubidium, cesium, and hydrogen-based frequency standards; and in cryogenic and trapped-ion technology; International and transnational applications of PTTI technology with emphasis on satellite laser tracking, GLONASS timing, intercomparison of national time scales and international telecommunications; Applications of PTTI technology to the telecommunications, power distribution, platform positioning, and geophysical survey industries; Applications of PTTI technology to evolving military communications and navigation systems; and Dissemination of precise time and frequency by means of Global Positioning System (GPS), Global Satellite Navigation System (GLONASS), MILSTAR, LORAN, and synchronous communications satellites.

Stokes-Einstein relation of the liquid metal rubidium and its relationship to changes in the microscopic dynamics with increasing temperature

NASA Astrophysics Data System (ADS)

Demmel, F.; Tani, A.

2018-06-01

For liquid rubidium the Stokes-Einstein (SE) relation is well fulfilled near the melting point with an effective hydrodynamic diameter, which agrees well with a value from structural investigations. A wealth of thermodynamic and microscopic data exists for a wide range of temperatures for liquid rubidium and hence it represents a good test bed to challenge the SE relation with rising temperature from an experimental point of view. We performed classical molecular dynamics simulations to complement the existing experimental data using a pseudopotential, which describes perfectly the structure and dynamics of liquid rubidium. The derived SE relation from combining experimental shear viscosity data with simulated diffusion coefficients reveals a weak violation at about 1.3 Tmelting≈400 K. The microscopic relaxation dynamics on nearest neighbor distances from neutron spectroscopy demonstrate distinct changes in the amplitude with rising temperature. The derived average relaxation time for density fluctuations on this length scale shows a non-Arrhenius behavior, with a slope change around 1.5 Tmelting≈450 K. Combining the simulated macroscopic self-diffusion coefficient with that microscopic average relaxation time, a distinct violation of the SE relation in the same temperature range can be demonstrated. One can conclude that the changes in the collective dynamics, a mirror of the correlated movements of the particles, are at the origin for the violation of the SE relation. The changes in the dynamics can be understood as a transition from a more viscous liquid metal to a more fluid-like liquid above the crossover temperature range of 1.3-1.5 Tmelting. The decay of the amplitude of density fluctuations in liquid aluminium, lead, and rubidium demonstrates a remarkable agreement and points to a universal thermal crossover in the dynamics of liquid metals.

Process for separation of zirconium-88, rubidium-83 and yttrium-88

DOEpatents

Heaton, Richard C.; Jamriska, Sr., David J.; Taylor, Wayne A.

1994-01-01

A process for selective separation of strontium-82 and strontium-85 from proton irradiated molybdenum targets is provided and includes dissolving the molybdenum target in a hydrogen peroxide solution to form a first ion-containing solution, passing the first ion-containing solution through a first cationic resin whereby ions selected from the group consisting of molybdenum, niobium, technetium, selenium, vanadium, arsenic, germanium, zirconium and rubidium remain in the first ion-containing solution while ions selected from the group consisting of rubidium, zinc, beryllium, cobalt, iron, manganese, chromium, strontium, yttrium and zirconium are selectively adsorbed by the first resin, contacting the first resin with an acid solution capable of stripping adsorbed ions from the first cationic exchange resin whereby the adsorbed ions are removed from the first resin to form a second ion-containing solution, evaporating the second ion-containing solution for time sufficient to remove substantially all of the acid and water from the second ion-containing solution whereby a residue remains, dissolving the residue from the evaporated second-ion containing solution in a dilute acid to form a third ion-containing solution, said third ion-containing solution having an acid molarity adapted to permit said ions to be adsorbed by a cationic exchange resin, passing the third ion-containing solution through a second cationic resin whereby the ions are adsorbed by the second resin, contacting the second resin with a dilute sulfuric acid solution whereby the adsorbed ions selected from the group consisting of rubidium, zinc, beryllium, cobalt, iron, manganese, chromium, and zirconium are selectively removed from the second resin, and contacting the second resin with a dilute acid solution whereby the adsorbed strontium ions are selectively removed. Zirconium, rubidium, and yttrium radioisotopes can also be recovered with additional steps.

Focusing Light Beams To Improve Atomic-Vapor Optical Buffers

NASA Technical Reports Server (NTRS)

Strekalov, Dmitry; Matsko, Andrey; Savchenkov, Anatoliy

2010-01-01

Specially designed focusing of light beams has been proposed as a means of improving the performances of optical buffers based on cells containing hot atomic vapors (e.g., rubidium vapor). There is also a companion proposal to improve performance by use of incoherent optical pumping under suitable conditions. Regarding the proposal to use focusing: The utility of atomic-vapor optical buffers as optical storage and processing devices has been severely limited by nonuniform spatial distributions of intensity in optical beams, arising from absorption of the beams as they propagate in atomic-vapor cells. Such nonuniformity makes it impossible to optimize the physical conditions throughout a cell, thereby making it impossible to optimize the performance of the cell as an optical buffer. In practical terms simplified for the sake of brevity, "to optimize" as used here means to design the cell so as to maximize the group delay of an optical pulse while keeping the absorption and distortion of the pulse reasonably small. Regarding the proposal to use incoherent optical pumping: For reasons too complex to describe here, residual absorption of light is one of the main impediments to achievement of desirably long group delays in hot atomic vapors. The present proposal is directed toward suppressing residual absorption of light. The idea of improving the performance of slow-light optical buffers by use of incoherent pumping overlaps somewhat with the basic idea of Raman-based slow-light systems. However, prior studies of those systems did not quantitatively answer the question of whether the performance of an atomic vapor or other medium that exhibits electromagnetically induced transparency (EIT) with Raman gain is superior to that of a medium that exhibits EIT without Raman gain.

Pulsed coherent population trapping with repeated queries for producing single-peaked high contrast Ramsey interference

NASA Astrophysics Data System (ADS)

Warren, Z.; Shahriar, M. S.; Tripathi, R.; Pati, G. S.

2018-02-01

A repeated query technique has been demonstrated as a new interrogation method in pulsed coherent population trapping for producing single-peaked Ramsey interference with high contrast. This technique enhances the contrast of the central Ramsey fringe by nearly 1.5 times and significantly suppresses the side fringes by using more query pulses ( >10) in the pulse cycle. Theoretical models have been developed to simulate Ramsey interference and analyze the characteristics of the Ramsey spectrum produced by the repeated query technique. Experiments have also been carried out employing a repeated query technique in a prototype rubidium clock to study its frequency stability performance.

Effect of Rubidium Incorporation on the Structural, Electrical, and Photovoltaic Properties of Methylammonium Lead Iodide-Based Perovskite Solar Cells.

PubMed

Park, Ik Jae; Seo, Seongrok; Park, Min Ah; Lee, Sangwook; Kim, Dong Hoe; Zhu, Kai; Shin, Hyunjung; Kim, Jin Young

2017-12-06

We report the electrical properties of rubidium-incorporated methylammonium lead iodide ((Rb x MA 1-x )PbI 3 ) films and the photovoltaic performance of (Rb x MA 1-x )PbI 3 film-based p-i-n-type perovskite solar cells (PSCs). The incorporation of a small amount of Rb + (x = 0.05) increases both the open circuit voltage (V oc ) and the short circuit photocurrent density (J sc ) of the PSCs, leading to an improved power conversion efficiency (PCE). However, a high fraction of Rb + incorporation (x = 0.1 and 0.2) decreases the J sc and thus the PCE, which is attributed to the phase segregation of the single tetragonal perovskite phase to a MA-rich tetragonal perovskite phase and a RbPbI 3 orthorhombic phase at high Rb fractions. Conductive atomic force microscopic and admittance spectroscopic analyses reveal that the single-phase (Rb 0.05 MA 0.95 )PbI 3 film has a high electrical conductivity because of a reduced deep-level trap density. We also found that Rb substitution enhances the diode characteristics of the PSC, as evidenced by the reduced reverse saturation current (J 0 ). The optimized (Rb x MA 1-x )PbI 3 PSCs exhibited a PCE of 18.8% with negligible hysteresis in the photocurrent-voltage curve. The results from this work enhance the understanding of the effect of Rb incorporation into organic-inorganic hybrid halide perovskites and enable the exploration of Rb-incorporated mixed perovskites for various applications, such as solar cells, photodetectors, and light-emitting diodes.

Spill-Resistant Alkali-Metal-Vapor Dispenser

NASA Technical Reports Server (NTRS)

Klipstein, William

2005-01-01

A spill-resistant vessel has been developed for dispensing an alkali-metal vapor. Vapors of alkali metals (most commonly, cesium or rubidium, both of which melt at temperatures slightly above room temperature) are needed for atomic frequency standards, experiments in spectroscopy, and experiments in laser cooling. Although the present spill-resistant alkali-metal dispenser was originally intended for use in the low-gravity environment of outer space, it can also be used in normal Earth gravitation: indeed, its utility as a vapor source was confirmed by use of cesium in a ground apparatus. The vessel is made of copper. It consists of an assembly of cylinders and flanges, shown in the figure. The uppermost cylinder is a fill tube. Initially, the vessel is evacuated, the alkali metal charge is distilled into the bottom of the vessel, and then the fill tube is pinched closed to form a vacuum seal. The innermost cylinder serves as the outlet for the vapor, yet prevents spilling by protruding above the surface of the alkali metal, no matter which way or how far the vessel is tilted. In the event (unlikely in normal Earth gravitation) that any drops of molten alkali metal have been shaken loose by vibration and are floating freely, a mesh cap on top of the inner cylinder prevents the drops from drifting out with the vapor. Liquid containment of the equivalent of 1.2 grams of cesium was confirmed for all orientations with rubbing alcohol in one of the prototypes later used with cesium.

Effects of hydrogen atom spin exchange collisions on atomic hydrogen maser oscillation frequency

NASA Technical Reports Server (NTRS)

Crampton, S. B.

1979-01-01

Frequency shifts due to collisions between hydrogen atoms in an atomic hydrogen maser frequency standard are studied. Investigations of frequency shifts proportional to the spin exchange frequency shift cross section and those proportional to the duration of exchange collisions are discussed. The feasibility of operating a hydrogen frequency standard at liquid helium temperatures is examined.

Alkaline and alkaline earth metal phosphate halides and phosphors

DOEpatents

Lyons, Robert Joseph; Setlur, Anant Achyut; Cleaver, Robert John

2012-11-13

Compounds, phosphor materials and apparatus related to nacaphite family of materials are presented. Potassium and rubidium based nacaphite family compounds and phosphors designed by doping divalent rare earth elements in the sites of alkaline earth metals in the nacaphite material families are descried. An apparatus comprising the phosphors based on the nacaphite family materials are presented herein. The compounds presented is of formula A.sub.2B.sub.1-yR.sub.yPO.sub.4X where the elements A, B, R, X and suffix y are defined such that A is potassium, rubidium, or a combination of potassium and rubidium and B is calcium, strontium, barium, or a combination of any of calcium, strontium and barium. X is fluorine, chlorine, or a combination of fluorine and chlorine, R is europium, samarium, ytterbium, or a combination of any of europium, samarium, and ytterbium, and y ranges from 0 to about 0.1.

Energy Pooling, Ion Recombination, and Reactions of Rubidium and Cesium in Hydrocarbon Gasses.

NASA Astrophysics Data System (ADS)

Bresler, Sean Michael; Park, J.; Heaven, Michael

2017-06-01

Diode Pumped Alkali Lasers (DPAL) are continuous wave lasers, potentially capable of megawatt average powers. These lasers exploit the D1 and D2 lines of alkali metals resulting in a 3-level laser with the lasing transition in the near infrared region of the electromagnetic spectrum. Energy pooling processes involving collisions between excited alkali metals cause a fraction of the gain media to be highly excited and eventually ionized. These high energy cesium atoms and ions chemically react with small hydrocarbons utilized as buffer gasses for the system, depleting the gain media. A kinetic model supported by experimental data is introduced to explain the cumulative effects of optical trapping, energy pooling, and chemical reactivity in heavy alkali metal (Rb, Cs) systems. Spectroscopic studies demonstrating metal hydride formation will also be presented.

On-demand semiconductor source of 780-nm single photons with controlled temporal wave packets

NASA Astrophysics Data System (ADS)

Béguin, Lucas; Jahn, Jan-Philipp; Wolters, Janik; Reindl, Marcus; Huo, Yongheng; Trotta, Rinaldo; Rastelli, Armando; Ding, Fei; Schmidt, Oliver G.; Treutlein, Philipp; Warburton, Richard J.

2018-05-01

We report on a fast, bandwidth-tunable single-photon source based on an epitaxial GaAs quantum dot. Exploiting spontaneous spin-flip Raman transitions, single photons at 780 nm are generated on demand with tailored temporal profiles of durations exceeding the intrinsic quantum dot lifetime by up to three orders of magnitude. Second-order correlation measurements show a low multiphoton emission probability [g2(0 ) ˜0.10 -0.15 ] at a generation rate up to 10 MHz. We observe Raman photons with linewidths as low as 200 MHz, which is narrow compared to the 1.1-GHz linewidth measured in resonance fluorescence. The generation of such narrow-band single photons with controlled temporal shapes at the rubidium wavelength is a crucial step towards the development of an optimized hybrid semiconductor-atom interface.

Transfer and conversion of images based on EIT in atom vapor.

PubMed

Cao, Mingtao; Zhang, Liyun; Yu, Ya; Ye, Fengjuan; Wei, Dong; Guo, Wenge; Zhang, Shougang; Gao, Hong; Li, Fuli

2014-05-01

Transfer and conversion of images between different wavelengths or polarization has significant applications in optical communication and quantum information processing. We demonstrated the transfer of images based on electromagnetically induced transparency (EIT) in a rubidium vapor cell. In experiments, a 2D image generated by a spatial light modulator is used as a coupling field, and a plane wave served as a signal field. We found that the image carried by coupling field could be transferred to that carried by signal field, and the spatial patterns of transferred image are much better than that of the initial image. It also could be much smaller than that determined by the diffraction limit of the optical system. We also studied the subdiffraction propagation for the transferred image. Our results may have applications in quantum interference lithography and coherent Raman spectroscopy.

Femtosecond laser fluorescence and propagation in very dense potassium vapor.

PubMed

Makdisi, Y; Kokaj, J; Afrousheh, K; Nair, R; Mathew, J; Pichler, G

2013-12-16

Femtosecond (fs) laser propagation and fluorescence of dense potassium vapor was studied, and the spectral region around the first and the second doublets of the principal series lines of potassium atoms was investigated. In our search we did not observe the conical emission in the far field, although it was previously observed in the case of rubidium. We discuss the possible reason of this unexpected result. The fluorescence spectrum revealed Rb impurity resonance lines in emission due to the collisional redistribution from the K(4p) levels into the Rb(5p) levels. In the forward propagation of 400 nm femtosecond light we observed the molecular band red shifted from potassium second doublet. However, no molecular spectrum was observed when the mode-locked fs laser light was discretely tuned within the wings of the first resonance lines, at 770 nm.

Emergence of currents as a transient quantum effect in nonequilibrium systems

NASA Astrophysics Data System (ADS)

Granot, Er'El; Marchewka, Avi

2011-09-01

Most current calculations are based on equilibrium or semi-equilibrium models. However, except for very special scenarios (like ring configuration), the current cannot exist in equilibrium. Moreover, unlike with equilibrium scenarios, there is no generic approach to confront out-of-equilibrium currents. In this paper we used recent studies on transient quantum mechanics to solve the current, which appears in the presence of very high density gradients and fast transients. It shows that the emerging current appears instantaneously, and although the density beyond the discontinuity is initially negligible the currents there have a finite value, and remain constant for a finite period. It is shown that this nonequilibrium effect can be measured in real experiments (such as cooled rubidium atoms), where the discontinuity is replaced with a finite width (hundreds of nanometers) gradient.

Collisional Dynamics of the Rubidium 5(2)P Levels

DTIC Science & Technology

1995-08-01

prepare the rubidium sample. This work established the cross-section for He collisions and bounded the cross-sections for Ne and Ar. Krause (49...continued the work by improving the measurement of the cross-sections and by adding the cross-sections for Kr, Xe and Rb collision partners. Krause ...number density of ,-r 1010 per cm 3 . This is an order of magnitude lower than the concentration reported by Krause (49) to prevent self trapping

Effect of a counterion on the glass transition temperature (T(g)') during lyophilization of ganciclovir salt forms.

PubMed

Kumar, Lokesh; Baheti, Ankit; Bansal, Arvind K

2011-02-07

This manuscript deals with the effect of a counterion on the glass transition temperature for lyophilization of ganciclovir salts. Salt forms of ganciclovir, namely, sodium, potassium, rubidium, and cesium salts, were prepared by an in situ technique and analyzed by modulated differential scanning calorimetry (MDSC) for the determination of the critical process parameter for lyophilization. Nonionized ganciclovir and its salt forms showed a glass transition (T(g)') in the reversing MDSC signal, confirming their amorphous nature. T(g)' of the nonionized ganciclovir and ganciclovir sodium, potassium, rubidium, and cesium salts followed the order: sodium salt (-34.94°C) > nonionized ganciclovir (-40.15°C) > potassium salt (-46.23°C) > rubidium salt (-49.95°C) > cesium salt (-53.62°C). The analysis of the freezable water content for ganciclovir and its salts showed the trend: pure water > nonionized ganciclovir > potassium salt ∼ sodium salt > rubidium salt > cesium salt. This showed that a majority of water in the salts is present as an unfrozen fraction, thus leading to a lowering of T(g)' because of the plasticizing effect of unfrozen water. Density functional theory (DFT) further suggested a positive contribution of the strength of intra- and intermolecular force of interactions to the T(g)' value, with a higher intramolecular and intermolecular force of interaction leading to a higher T(g)'.

Transverse effects in nonlinear optics: Toward the photon superfluid

NASA Astrophysics Data System (ADS)

McCormick, Colin Fraser

Nonlinear optics displays a wealth of transverse effects. These effects are particularly rich in the presence of an optical cavity. Many considerations suggest that in a Kerr nonlinear cavity a new state of light known as a "photon superfluid" can form, with strong analogies to atomic superfluids. The conditions for the formation of the photon superfluid include requirements on the cavity, input light fields and the nonlinear medium as well as various timescales. The most favorable candidate nonlinear medium for observing the photon super-fluid is an atomic vapor. With a strong and fast Kerr effect, atomic vapors also have the advantage of a Kerr coefficient that is tunable in both magnitude and sign. A series of z-scan experiments in far-detuned atomic rubidium vapor is reported, measuring the Kerr coefficient and determining its functional dependence on detuning to be that of a Doppler-broadened two-level model with adiabatic following of the electric field by the atom pseudomoment. Saturation effects are found to be important. Z-scan measurements for detunings within the Doppler profile are shown to agree well with numerical simulations based on the Doppler-broadened model. Agreement between absorptive and refractive non-linear coefficients is evidence of the Kramers-Kronig relations at work, even in this nonlinear system. The formation of the photon superfluid is discussed and the calculation of a new process, nearly collinear four-wave mixing, is presented. This process is essentially an inverse beam filamentation that is likely to be the underlying physical mechanism for transverse cooling and condensation of photons in a nonlinear optical cavity. Nearly collinear four-wave mixing may also be related to phenomena in general nonlinear physics, including modulation instability and Fermi-Pasta-Ulam recurrence.

Development of a sub-miniature rubidium oscillator for SEEKTALK application

NASA Technical Reports Server (NTRS)

Fruehauf, H.; Weidemann, W.; Jechart, E.

1981-01-01

Warm-up and size challenges to oscillator construction are presented as well as the problems involved in these tasks. The performance of M-100 military rubidium oscillator is compared to that of a subminiture rubididum oscillator (M-1000). Methods of achieving 1.5 minute warm-up are discussed as well as improvements in performance under adverse environmental conditions, including temperature, vibration, and magnetics. An attempt is made to construct an oscillator error budget under a set of arbitrary mission conditions.

Rubidium-strontium date of possibly 3 billion years for a granitic rock from antarctica.

PubMed

Halpern, M

1970-09-04

A single total rock sample of biotite granite from Jule Peaks, Antarctica, has been dated by the rubidium-strontium method at about 3 billion years. The juxtaposition of this sector of Antarctica with Africa in the Dietz and Sproll continental drift reconstruction results in a possible geochronologic fit of the Princess Martha Coast of Antarctica with a covered possible notheastern extension of the African Swaziland Shield, which contains granitic rocks that are also 3 billion years old.

Phase equilibria and crystal chemistry of rubidium niobates and rubidium tantalates

NASA Technical Reports Server (NTRS)

Minor, D. B.; Roth, R. S.; Parker, H. S.; Brower, W. S.

1977-01-01

The phase equilibria relations and crystal chemistry of portions of the Rb2O-Nb2O5 and Rb2O-Ta2O5 systems were investigated for structures potentially useful as ionic conductors. A hexagonal tungsten bronze-type (HTB) structure was found in both systems as well as three hexagonal phases with mixed HTB-pyrochlore type structures. Ion exchange experiments between various alkali ions are described for several phases. Unit cell dimensions and X-ray diffraction powder patterns are reported.

Rubidium-87 gas cell studies, phase 1

NASA Technical Reports Server (NTRS)

Vanier, J.

1972-01-01

The construction of a quartz bulb-quartz cavity type rubidium maser is described, and the results obtained with two of these masers are presented. The tuning characteristics, medium term stability, and short term stability are reported. It is concluded that the stability of the masers in the short term region is superior to any of the oscillators presently existing. On this basis it is believed that future development of the masers to reduce their size and improve their medium term stability is well justified.

Frequency stability degradation of an oscillator slaved to a periodically interrogated atomic resonator.

PubMed

Santarelli, G; Audoin, C; Makdissi, A; Laurent, P; Dick, G J; Clairon, A

1998-01-01

Atomic frequency standards using trapped ions or cold atoms work intrinsically in a pulsed mode. Theoretically and experimentally, this mode of operation has been shown to lead to a degradation of the frequency stability due to the frequency noise of the interrogation oscillator. In this paper a physical analysis of this effect has been made by evaluating the response of a two-level atom to the interrogation oscillator phase noise in Ramsey and multi-Rabi interrogation schemes using a standard quantum mechanical approach. This response is then used to calculate the degradation of the frequency stability of a pulsed atomic frequency standard such as an atomic fountain or an ion trap standard. Comparison is made to an experimental evaluation of this effect in the LPTF Cs fountain frequency standard, showing excellent agreement.

Effect of Rubidium Incorporation on the Structural, Electrical, and Photovoltaic Properties of Methylammonium Lead Iodide-Based Perovskite Solar Cells

DOE PAGES

Park, Ik Jae; Seo, Seongrok; Park, Min Ah; ...

2017-11-10

We report the electrical properties of rubidium-incorporated methylammonium lead iodide ((Rb xMA 1-x)PbI 3) films and the photovoltaic performance of (Rb xMA 1-x)PbI 3 film-based p-i-n-type perovskite solar cells (PSCs). The incorporation of a small amount of Rb + (x = 0.05) increases both the open circuit voltage (V oc) and the short circuit photocurrent density (J sc) of the PSCs, leading to an improved power conversion efficiency (PCE). However, a high fraction of Rb + incorporation (x = 0.1 and 0.2) decreases the J sc and thus the PCE, which is attributed to the phase segregation of the singlemore » tetragonal perovskite phase to a MA-rich tetragonal perovskite phase and a RbPbI 3 orthorhombic phase at high Rb fractions. Conductive atomic force microscopic and admittance spectroscopic analyses reveal that the single-phase (Rb 0.05MA 0.95)PbI 3 film has a high electrical conductivity because of a reduced deep-level trap density. We also found that Rb substitution enhances the diode characteristics of the PSC, as evidenced by the reduced reverse saturation current (J 0). The optimized (Rb xMA 1-x)PbI 3 PSCs exhibited a PCE of 18.8% with negligible hysteresis in the photocurrent-voltage curve. The results from this work enhance the understanding of the effect of Rb incorporation into organic-inorganic hybrid halide perovskites and enable the exploration of Rb-incorporated mixed perovskites for various applications, such as solar cells, photodetectors, and light-emitting diodes.« less

Effect of Rubidium Incorporation on the Structural, Electrical, and Photovoltaic Properties of Methylammonium Lead Iodide-Based Perovskite Solar Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Ik Jae; Seo, Seongrok; Park, Min Ah

We report the electrical properties of rubidium-incorporated methylammonium lead iodide ((Rb xMA 1-x)PbI 3) films and the photovoltaic performance of (Rb xMA 1-x)PbI 3 film-based p-i-n-type perovskite solar cells (PSCs). The incorporation of a small amount of Rb + (x = 0.05) increases both the open circuit voltage (V oc) and the short circuit photocurrent density (J sc) of the PSCs, leading to an improved power conversion efficiency (PCE). However, a high fraction of Rb + incorporation (x = 0.1 and 0.2) decreases the J sc and thus the PCE, which is attributed to the phase segregation of the singlemore » tetragonal perovskite phase to a MA-rich tetragonal perovskite phase and a RbPbI 3 orthorhombic phase at high Rb fractions. Conductive atomic force microscopic and admittance spectroscopic analyses reveal that the single-phase (Rb 0.05MA 0.95)PbI 3 film has a high electrical conductivity because of a reduced deep-level trap density. We also found that Rb substitution enhances the diode characteristics of the PSC, as evidenced by the reduced reverse saturation current (J 0). The optimized (Rb xMA 1-x)PbI 3 PSCs exhibited a PCE of 18.8% with negligible hysteresis in the photocurrent-voltage curve. The results from this work enhance the understanding of the effect of Rb incorporation into organic-inorganic hybrid halide perovskites and enable the exploration of Rb-incorporated mixed perovskites for various applications, such as solar cells, photodetectors, and light-emitting diodes.« less

Theoretical simulations of protective thin film Fabry-Pérot filters for integrated optical elements of diode pumped alkali lasers (DPAL)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quarrie, L., E-mail: Lindsay.Quarrie@l-3com.com, E-mail: lindsay.o.quarrie@gmail.com; Air Force Research Laboratory, AFRL/RDLC Laser CoE, 3550 Aberdeen Avenue SE, Kirtland AFB, NM 87117-5776

The lifetime of Diode-Pumped Alkali Lasers (DPALs) is limited by damage initiated by reaction of the glass envelope of its gain medium with rubidium vapor. Rubidium is absorbed into the glass and the rubidium cations diffuse through the glass structure, breaking bridging Si-O bonds. A damage-resistant thin film was developed enhancing high-optical transmission at natural rubidium resonance input and output laser beam wavelengths of 780 nm and 795 nm, while protecting the optical windows of the gain cell in a DPAL. The methodology developed here can be readily modified for simulation of expected transmission performance at input pump and outputmore » laser wavelengths using different combination of thin film materials in a DPAL. High coupling efficiency of the light through the gas cell was accomplished by matching the air-glass and glass-gas interfaces at the appropriate wavelengths using a dielectric stack of high and low index of refraction materials selected to work at the laser energies and protected from the alkali metal vapor in the gain cell. Thin films as oxides of aluminum, zirconium, tantalum, and silicon were selected allowing the creation of Fabry-Perot optical filters on the optical windows achieving close to 100% laser transmission in a solid optic combination of window and highly reflective mirror. This approach allows for the development of a new whole solid optic laser.« less

Experimental study of discrete diffraction behavior in a coherent atomic system

NASA Astrophysics Data System (ADS)

Yuan, Jinpeng; Li, Yihong; Li, Shaohua; Li, Changyong; Wang, Lirong; Xiao, Liantuan; Jia, Suotang

2017-12-01

Discrete diffraction behavior was experimentally studied in a coherent rubidium 5S 1/2  -  5P 3/2  -  5D 5/2 cascade system. An optical lattice was established by the interference of two coupling lasers corresponding to 5P 3/2  -  5D 5/2 transition with a small angle. The distinct discrete diffraction patterns were observed in vapor when the probe laser corresponding to the 5S 1/2  -  5P 3/2 transition propagated through the optical lattice. The optimized pertinent experimental parameters such as vapor temperature, two-photon detuning, coupling laser intensity and probe laser intensity are obtained. The experimental results are well analyzed utilizing the density-matrix theory. This system provides a new approach to investigate non-Hermitian physics and discrete solitons.

Towards terahertz detection and calibration through spontaneous parametric down-conversion in the terahertz idler-frequency range generated by a 795 nm diode laser system

NASA Astrophysics Data System (ADS)

Kornienko, Vladimir V.; Kitaeva, Galiya Kh.; Sedlmeir, Florian; Leuchs, Gerd; Schwefel, Harald G. L.

2018-05-01

We study a calibration scheme for terahertz wave nonlinear-optical detectors based on spontaneous parametric down-conversion. Contrary to the usual low wavelength pump in the green, we report here on the observation of spontaneous parametric down-conversion originating from an in-growth poled lithium niobate crystal pumped with a continuous wave 50 mW, 795 nm diode laser system, phase-matched to a terahertz frequency idler wave. Such a system is more compact and allows for longer poling periods as well as lower losses in the crystal. Filtering the pump radiation by a rubidium-87 vapor cell allowed the frequency-angular spectra to be obtained down to ˜0.5 THz or ˜1 nm shift from the pump radiation line. The presence of an amplified spontaneous emission "pedestal" in the diode laser radiation spectrum significantly hampers the observation of spontaneous parametric down-conversion spectra, in contrast to conventional narrowband gas lasers. Benefits of switching to longer pump wavelengths are pointed out, such as collinear optical-terahertz phase-matching in bulk crystals.

Compressed Sensing for Chemistry

NASA Astrophysics Data System (ADS)

Sanders, Jacob Nathan

Many chemical applications, from spectroscopy to quantum chemistry, involve measuring or computing a large amount of data, and then compressing this data to retain the most chemically-relevant information. In contrast, compressed sensing is an emergent technique that makes it possible to measure or compute an amount of data that is roughly proportional to its information content. In particular, compressed sensing enables the recovery of a sparse quantity of information from significantly undersampled data by solving an ℓ 1-optimization problem. This thesis represents the application of compressed sensing to problems in chemistry. The first half of this thesis is about spectroscopy. Compressed sensing is used to accelerate the computation of vibrational and electronic spectra from real-time time-dependent density functional theory simulations. Using compressed sensing as a drop-in replacement for the discrete Fourier transform, well-resolved frequency spectra are obtained at one-fifth the typical simulation time and computational cost. The technique is generalized to multiple dimensions and applied to two-dimensional absorption spectroscopy using experimental data collected on atomic rubidium vapor. Finally, a related technique known as super-resolution is applied to open quantum systems to obtain realistic models of a protein environment, in the form of atomistic spectral densities, at lower computational cost. The second half of this thesis deals with matrices in quantum chemistry. It presents a new use of compressed sensing for more efficient matrix recovery whenever the calculation of individual matrix elements is the computational bottleneck. The technique is applied to the computation of the second-derivative Hessian matrices in electronic structure calculations to obtain the vibrational modes and frequencies of molecules. When applied to anthracene, this technique results in a threefold speed-up, with greater speed-ups possible for larger molecules. The implementation of the method in the Q-Chem commercial software package is described. Moreover, the method provides a general framework for bootstrapping cheap low-accuracy calculations in order to reduce the required number of expensive high-accuracy calculations.

Blood pool and tissue phase patient motion effects on 82rubidium PET myocardial blood flow quantification.

PubMed

Lee, Benjamin C; Moody, Jonathan B; Poitrasson-Rivière, Alexis; Melvin, Amanda C; Weinberg, Richard L; Corbett, James R; Ficaro, Edward P; Murthy, Venkatesh L

2018-03-23

Patient motion can lead to misalignment of left ventricular volumes of interest and subsequently inaccurate quantification of myocardial blood flow (MBF) and flow reserve (MFR) from dynamic PET myocardial perfusion images. We aimed to identify the prevalence of patient motion in both blood and tissue phases and analyze the effects of this motion on MBF and MFR estimates. We selected 225 consecutive patients that underwent dynamic stress/rest rubidium-82 chloride ( 82 Rb) PET imaging. Dynamic image series were iteratively reconstructed with 5- to 10-second frame durations over the first 2 minutes for the blood phase and 10 to 80 seconds for the tissue phase. Motion shifts were assessed by 3 physician readers from the dynamic series and analyzed for frequency, magnitude, time, and direction of motion. The effects of this motion isolated in time, direction, and magnitude on global and regional MBF and MFR estimates were evaluated. Flow estimates derived from the motion corrected images were used as the error references. Mild to moderate motion (5-15 mm) was most prominent in the blood phase in 63% and 44% of the stress and rest studies, respectively. This motion was observed with frequencies of 75% in the septal and inferior directions for stress and 44% in the septal direction for rest. Images with blood phase isolated motion had mean global MBF and MFR errors of 2%-5%. Isolating blood phase motion in the inferior direction resulted in mean MBF and MFR errors of 29%-44% in the RCA territory. Flow errors due to tissue phase isolated motion were within 1%. Patient motion was most prevalent in the blood phase and MBF and MFR errors increased most substantially with motion in the inferior direction. Motion correction focused on these motions is needed to reduce MBF and MFR errors.

Hard Collisions in Rubidium using Sub-Doppler Spectroscopy

DTIC Science & Technology

2010-03-01

γdiff and the loss due to electronic collisions γdisch can be ignored in this work. The collisional rate γcoll can also be ignored because the quenching ...rate for ground state rubidium is very, very small. Another way to say it, it takes significant energy (very high temperatures) for 14 quenching of the...component fiso = relative natural abundance fF ′′ = statistical distribution of population among F” states = (2F ′′+1)e −E(F ′′) kBTP F”(2F ′′+1)e

Analysis of the X-ray emission spectra of copper, germanium and rubidium plasmas produced at the Phelix laser facility

NASA Astrophysics Data System (ADS)

Comet, M.; Pain, J.-C.; Gilleron, F.; Piron, R.; Denis-Petit, D.; Méot, V.; Gosselin, G.; Morel, P.; Hannachi, F.; Gobet, F.; Tarisien, M.; Versteegen, M.

2017-03-01

We present the analysis of X-ray emission spectra of copper, germanium and rubidium plasmas measured at the Phelix laser facility. The laser intensity was around 6×1014 W.cm-2. The analysis is based on the hypothesis of an homogeneous plasma in local thermodynamic equilibrium using an effective temperature. This temperature is deduced from hydrodynamic simulations and collisional-radiative computations. Spectra are then calculated using the LTE opacity codes OPAMCDF and SCO-RCG and compared to experimental data.

Inductively guided circuits for ultracold dressed atoms

PubMed Central

Sinuco-León, German A.; Burrows, Kathryn A.; Arnold, Aidan S.; Garraway, Barry M.

2014-01-01

Recent progress in optics, atomic physics and material science has paved the way to study quantum effects in ultracold atomic alkali gases confined to non-trivial geometries. Multiply connected traps for cold atoms can be prepared by combining inhomogeneous distributions of DC and radio-frequency electromagnetic fields with optical fields that require complex systems for frequency control and stabilization. Here we propose a flexible and robust scheme that creates closed quasi-one-dimensional guides for ultracold atoms through the ‘dressing’ of hyperfine sublevels of the atomic ground state, where the dressing field is spatially modulated by inductive effects over a micro-engineered conducting loop. Remarkably, for commonly used atomic species (for example, 7Li and 87Rb), the guide operation relies entirely on controlling static and low-frequency fields in the regimes of radio-frequency and microwave frequencies. This novel trapping scheme can be implemented with current technology for micro-fabrication and electronic control. PMID:25348163

Chemical Trends in Solid Alkali Pertechnetates.

PubMed

Weaver, Jamie; Soderquist, Chuck Z; Washton, Nancy M; Lipton, Andrew S; Gassman, Paul L; Lukens, Wayne W; Kruger, Albert A; Wall, Nathalie A; McCloy, John S

2017-03-06

Insight into the solid-state chemistry of pure technetium-99 ( 99 Tc) oxides is required in the development of a robust immobilization and disposal system for nuclear waste stemming from the radiopharmaceutical industry, from the production of nuclear weapons, and from spent nuclear fuel. However, because of its radiotoxicity and the subsequent requirement of special facilities and handling procedures for research, only a few studies have been completed, many of which are over 20 years old. In this study, we report the synthesis of pure alkali pertechnetates (sodium, potassium, rubidium, and cesium) and analysis of these compounds by Raman spectroscopy, X-ray absorption spectroscopy (XANES and EXAFS), solid-state nuclear magnetic resonance (static and magic angle spinning), and neutron diffraction. The structures and spectral signatures of these compounds will aid in refining the understanding of 99 Tc incorporation into and release from nuclear waste glasses. NaTcO 4 shows aspects of the relatively higher electronegativity of the Na atom, resulting in large distortions of the pertechnetate tetrahedron and deshielding of the 99 Tc nucleus relative to the aqueous TcO 4 - . At the other extreme, the large Cs and Rb atoms interact only weakly with the pertechnetate, have closer to perfect tetrahedral symmetry at the Tc atom, and have very similar vibrational spectra, even though the crystal structure of CsTcO 4 is orthorhombic while that of RbTcO 4 is tetragonal. Further trends are observed in the cell volume and quadrupolar coupling constant.

Chemical Trends in Solid Alkali Pertechnetates

DOE PAGES

Weaver, Jamie; Soderquist, Chuck Z.; Washton, Nancy M.; ...

2017-02-21

Insight into the solid-state chemistry of pure technetium-99 ( 99Tc) oxides is required in the development of a robust immobilization and disposal system for nuclear waste stemming from the radiopharmaceutical industry, from the production of nuclear weapons, and from spent nuclear fuel. However, because of its radiotoxicity and the subsequent requirement of special facilities and handling procedures for research, only a few studies have been completed, many of which are over 20 years old. In this study, we report the synthesis of pure alkali pertechnetates (sodium, potassium, rubidium, and cesium) and analysis of these compounds by Raman spectroscopy, X-ray absorptionmore » spectroscopy (XANES and EXAFS), solid-state nuclear magnetic resonance (static and magic angle spinning), and neutron diffraction. The structures and spectral signatures of these compounds will aid in refining the understanding of 99Tc incorporation into and release from nuclear waste glasses. NaTcO 4 shows aspects of the relatively higher electronegativity of the Na atom, resulting in large distortions of the pertechnetate tetrahedron and deshielding of the 99Tc nucleus relative to the aqueous TcO 4 –. At the other extreme, the large Cs and Rb atoms interact only weakly with the pertechnetate, have closer to perfect tetrahedral symmetry at the Tc atom, and have very similar vibrational spectra, even though the crystal structure of CsTcO 4 is orthorhombic while that of RbTcO 4 is tetragonal. Further trends are observed in the cell volume and quadrupolar coupling constant.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weaver, Jamie; Soderquist, Chuck Z.; Washton, Nancy M.

Insight into the solid-state chemistry of pure technetium-99 ( 99Tc) oxides is required in the development of a robust immobilization and disposal system for nuclear waste stemming from the radiopharmaceutical industry, from the production of nuclear weapons, and from spent nuclear fuel. However, because of its radiotoxicity and the subsequent requirement of special facilities and handling procedures for research, only a few studies have been completed, many of which are over 20 years old. In this study, we report the synthesis of pure alkali pertechnetates (sodium, potassium, rubidium, and cesium) and analysis of these compounds by Raman spectroscopy, X-ray absorptionmore » spectroscopy (XANES and EXAFS), solid-state nuclear magnetic resonance (static and magic angle spinning), and neutron diffraction. The structures and spectral signatures of these compounds will aid in refining the understanding of 99Tc incorporation into and release from nuclear waste glasses. NaTcO 4 shows aspects of the relatively higher electronegativity of the Na atom, resulting in large distortions of the pertechnetate tetrahedron and deshielding of the 99Tc nucleus relative to the aqueous TcO 4 –. At the other extreme, the large Cs and Rb atoms interact only weakly with the pertechnetate, have closer to perfect tetrahedral symmetry at the Tc atom, and have very similar vibrational spectra, even though the crystal structure of CsTcO 4 is orthorhombic while that of RbTcO 4 is tetragonal. Further trends are observed in the cell volume and quadrupolar coupling constant.« less

Transparent electrodes for high E-field production using a buried indium tin oxide layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gunton, Will; Polovy, Gene; Semczuk, Mariusz

2016-03-15

We present a design and characterization of optically transparent electrodes suitable for atomic and molecular physics experiments where high optical access is required. The electrodes can be operated in air at standard atmospheric pressure and do not suffer electrical breakdown even for electric fields far exceeding the dielectric breakdown of air. This is achieved by putting an indium tin oxide coated dielectric substrate inside a stack of dielectric substrates, which prevents ion avalanche resulting from Townsend discharge. With this design, we observe no arcing for fields of up to 120 kV/cm. Using these plates, we directly verify the production ofmore » electric fields up to 18 kV/cm inside a quartz vacuum cell by a spectroscopic measurement of the dc Stark shift of the 5{sup 2}S{sub 1/2} → 5{sup 2}P{sub 3/2} transition for a cloud of laser cooled rubidium atoms. We also report on the shielding of the electric field and on the residual electric fields that persist within the vacuum cell once the electrodes are discharged. In addition, we discuss observed atom loss that results from the motion of free charges within the vacuum. The observed asymmetry of these phenomena on the bias of the electrodes suggests that field emission of electrons within the vacuum is primarily responsible for these effects and may indicate a way of mitigating them.« less

Kinetics of Alkaline Decomposition and Cyaniding of Argentian Rubidium Jarosite in NaOH Medium

NASA Astrophysics Data System (ADS)

Rodríguez, Eleazar Salinas; Sáenz, Eduardo Cerecedo; Ramírez, Marius; Cardona, Francisco Patiño; Labra, Miguel Pérez

2012-10-01

The alkaline decomposition of Argentian rubidium jarosite in NaOH media is characterized by an induction period and a progressive conversion period in which the sulfate and rubidium ions pass to the solution, leaving an amorphous iron hydroxide residue. The process is chemically controlled and the order of reaction with respect to hydroxide concentration in the range of 1.75 and 20.4 mol OH- m-3 is 0.94, while activation energy in the range of temperatures of 298 K to 328 K (25 °C to 55 °C) is 91.3 kJ mol-1. Cyaniding of Argentian rubidium jarosite in NaOH media presents a reaction order of 0 with respect to NaCN concentration (in the range of 5 to 41 mol m-3) and an order of reaction of 0.62 with respect to hydroxide concentration, in the range of 1.1 and 30 mol [OH-] m-3. In this case, the cyaniding process can be described, as in other jarosites, as the following two-step process: (1) a step (slow) of alkaline decomposition that controls the overall process followed by (2) a fast step of silver complexation. The activation energy during cyaniding in the range of temperatures of 298 K to 333 K (25 °C to 60 °C) is 43.5 kJ mol-1, which is characteristic of a process controlled by chemical reaction. These results are quite similar to that observed for several synthetic jarosites and that precipitated in a zinc hydrometallurgical plant (Industrial Minera México, San Luis Potosi).

Detection of NMR signals with a radio-frequency atomic magnetometer.

PubMed

Savukov, I M; Seltzer, S J; Romalis, M V

2007-04-01

We demonstrate detection of proton NMR signals with a radio-frequency (rf) atomic magnetometer tuned to the NMR frequency of 62 kHz. High-frequency operation of the atomic magnetometer makes it relatively insensitive to ambient magnetic field noise. We obtain magnetic field sensitivity of 7 fT/Hz1/2 using only a thin aluminum shield. We also derive an expression for the fundamental sensitivity limit of a surface inductive pick-up coil as a function of frequency and find that an atomic rf magnetometer is intrinsically more sensitive than a coil of comparable size for frequencies below about 50 MHz.

Ingested plastic as a route for trace metals in Laysan Albatross (Phoebastria immutabilis) and Bonin Petrel (Pterodroma hypoleuca) from Midway Atoll.

PubMed

Lavers, Jennifer L; Bond, Alexander L

2016-09-15

Seabirds are declining faster than any other group of birds, with plastic ingestion and associated contaminants linked to negative impacts on marine wildlife, including >170 seabird species. To provide quantitative data on the effects of plastic pollution, we sampled feathers and stomach contents from Laysan Albatross (Phoebastria immutabilis) and Bonin Petrel (Pterodroma hypoleuca) on Midway Atoll, North Pacific Ocean, and assessed our ability to detect change over time by synthesizing previous studies. Between 25 and 100% of fledglings exceed international targets for plastic ingestion by seabirds. High levels of ingested plastic were correlated with increased concentrations of chlorine, iron, lead, manganese, and rubidium in feathers. The frequency of plastic ingestion by Laysan Albatross and concentration of some elements in both species is increasing, suggesting deterioration in the health of the marine environment. Variability in the frequency of plastic ingestion by Laysan Albatross may limit their utility as an indicator species. Copyright © 2016 Elsevier Ltd. All rights reserved.

A rubidium traced white-light etalon calibrator for MAROON-X

NASA Astrophysics Data System (ADS)

Stürmer, Julian; Seifahrt, Andreas; Schwab, Christian; Bean, Jacob L.

2016-07-01

We report on the construction and testing of a vacuum-gap Fabry-Perot etalon calibrator for high precision radial velocity spectrographs. The etalon is referenced against hyper fine transitions of rubidium to provide a precise wavelength calibrator for MAROON-X, a new fiber-fed, red-optical, high-precision radial-velocity spectrograph currently under construction for one of the twin 6.5m Magellan Telescopes in Chile. We demonstrate a turnkey system, ready to be installed at any current and next generation radial velocity spectrograph that requires calibration over a wide spectral band-pass. Uncertainties in the position of one etalon line are at the 10 cm s-1 level in individual measurements taken at 4 Hz. Our long-term stability is mainly limited by aging effects of the spacer material Zerodur, which imprints a 12 cm s-1 daily drift. However, as the etalon position is traced by the rubidium reference with a precision of <3 cm s-1 for integration times longer than 10s, we can fully account for this effect at the RV data reduction level.

Fast phase stabilization of a low frequency beat note for atom interferometry.

PubMed

Oh, E; Horne, R A; Sackett, C A

2016-06-01

Atom interferometry experiments rely on the ability to obtain a stable signal that corresponds to an atomic phase. For interferometers that use laser beams to manipulate the atoms, noise in the lasers can lead to errors in the atomic measurement. In particular, it is often necessary to actively stabilize the optical phase between two frequency components of the beams. Typically this is achieved using a time-domain measurement of a beat note between the two frequencies. This becomes challenging when the frequency difference is small and the phase measurement must be made quickly. The method presented here instead uses a spatial interference detection to rapidly measure the optical phase for arbitrary frequency differences. A feedback system operating at a bandwidth of about 10 MHz could then correct the phase in about 3 μs. This time is short enough that the phase correction could be applied at the start of a laser pulse without appreciably degrading the fidelity of the atom interferometer operation. The phase stabilization system was demonstrated in a simple atom interferometer measurement of the (87)Rb recoil frequency.

Experimental observation of spatial quantum noise reduction below the standard quantum limit with bright twin beams of light

NASA Astrophysics Data System (ADS)

Kumar, Ashok; Nunley, Hayden; Marino, Alberto

2016-05-01

Quantum noise reduction (QNR) below the standard quantum limit (SQL) has been a subject of interest for the past two to three decades due to its wide range of applications in quantum metrology and quantum information processing. To date, most of the attention has focused on the study of QNR in the temporal domain. However, many areas in quantum optics, specifically in quantum imaging, could benefit from QNR not only in the temporal domain but also in the spatial domain. With the use of a high quantum efficiency electron multiplier charge coupled device (EMCCD) camera, we have observed spatial QNR below the SQL in bright narrowband twin light beams generated through a four-wave mixing (FWM) process in hot rubidium atoms. Owing to momentum conservation in this process, the twin beams are momentum correlated. This leads to spatial quantum correlations and spatial QNR. Our preliminary results show a spatial QNR of over 2 dB with respect to the SQL. Unlike previous results on spatial QNR with faint and broadband photon pairs from parametric down conversion (PDC), we demonstrate spatial QNR with spectrally and spatially narrowband bright light beams. The results obtained will be useful for atom light interaction based quantum protocols and quantum imaging. Work supported by the W.M. Keck Foundation.

The Generation and Detection of Rydberg Wavepackets

NASA Astrophysics Data System (ADS)

Meyler, P. E.

Available from UMI in association with The British Library. Requires signed TDF. A Rydberg wavepacket is a coherent superposition of several electronic energy eigenstates corresponding to the high lying energy levels of an atom. In this thesis, an experiment is described in which a radially localized Rydberg wavepacket is excited in atomic rubidium by a picosecond optical pump pulse. The wavepacket has a mean effective principal quantum number v_0 = 62, which corresponds to a classical orbit period T _{rm cl} = 37 ps. The subsequent evolution of the wavepacket is probed by a delayed, picosecond optical pulse. The resulting photoionization signal is measured as a function of pump-probe delay, and initially displays peaks separated by T_{rm cl}. This classical oscillation then collapses, after which a fractional revival of period T_ {rm cl}/2 is observed, followed finally by a full revival of the wavepacket. These results constitute the first experimental observation of a fractional revival in any system, and are shown to be in good agreement with theoretical predictions. The results of the experiment are discussed with reference to the correspondence principle and it is concluded that even in the limit of large quantum numbers, the evolution of a given system can be dominated by quantum mechanical effects.

Emission characteristics of plasma based on xenon-rubidium bromide mixture

NASA Astrophysics Data System (ADS)

Heneral, A. A.; Avtaeva, S. V.

2017-10-01

Luminescence spectra of a longitudinal pulse-periodic discharge in xenon mixture with rubidium bromide vapors (Xe-RbBr) are studied experimentally at low pressures. The conditions leading to the appearance of intense bands of ultraviolet radiation of exciplex XeBr* molecules in the spectral interval between 200 and 400 nm are found. The highest yield of UV radiation of XeBr* molecules is achieved when the temperature of discharge-tube walls is equal to 750°C. A maximum power of UV radiation from the entire plasma volume as high as 4.8 W is obtained.

Review: comparison of PET rubidium-82 with conventional SPECT myocardial perfusion imaging

PubMed Central

Ghotbi, Adam A; Kjær, Andreas; Hasbak, Philip

2014-01-01

Nuclear cardiology has for many years been focused on gamma camera technology. With ever improving cameras and software applications, this modality has developed into an important assessment tool for ischaemic heart disease. However, the development of new perfusion tracers has been scarce. While cardiac positron emission tomography (PET) so far largely has been limited to centres with on-site cyclotron, recent developments with generator produced perfusion tracers such as rubidium-82, as well as an increasing number of PET scanners installed, may enable a larger patient flow that may supersede that of gamma camera myocardial perfusion imaging. PMID:24028171

Momentum-resolved radio-frequency spectroscopy of a spin-orbit-coupled atomic Fermi gas near a Feshbach resonance in harmonic traps

NASA Astrophysics Data System (ADS)

Peng, Shi-Guo; Liu, Xia-Ji; Hu, Hui; Jiang, Kaijun

2012-12-01

We theoretically investigate the momentum-resolved radio-frequency spectroscopy of a harmonically trapped atomic Fermi gas near a Feshbach resonance in the presence of equal Rashba and Dresselhaus spin-orbit coupling. The system is qualitatively modeled as an ideal gas mixture of atoms and molecules, in which the properties of molecules, such as the wave function, binding energy, and effective mass, are determined from the two-particle solution of two interacting atoms. We calculate separately the radio-frequency response from atoms and molecules at finite temperatures by using the standard Fermi golden rule and take into account the effect of harmonic traps within local density approximation. The total radio-frequency spectroscopy is discussed as functions of temperature and spin-orbit coupling strength. Our results give a qualitative picture of radio-frequency spectroscopy of a resonantly interacting spin-orbit-coupled Fermi gas and can be directly tested in atomic Fermi gases of 40K atoms at Shanxi University and 6Li atoms at the Massachusetts Institute of Technology.

Dispersive detection of radio-frequency-dressed states

NASA Astrophysics Data System (ADS)

Jammi, Sindhu; Pyragius, Tadas; Bason, Mark G.; Florez, Hans Marin; Fernholz, Thomas

2018-04-01

We introduce a method to dispersively detect alkali-metal atoms in radio-frequency-dressed states. In particular, we use dressed detection to measure populations and population differences of atoms prepared in their clock states. Linear birefringence of the atomic medium enables atom number detection via polarization homodyning, a form of common path interferometry. In order to achieve low technical noise levels, we perform optical sideband detection after adiabatic transformation of bare states into dressed states. The balanced homodyne signal then oscillates independently of field fluctuations at twice the dressing frequency, thus allowing for robust, phase-locked detection that circumvents low-frequency noise. Using probe pulses of two optical frequencies, we can detect both clock states simultaneously and obtain population difference as well as the total atom number. The scheme also allows for difference measurements by direct subtraction of the homodyne signals at the balanced detector, which should technically enable quantum noise limited measurements with prospects for the preparation of spin squeezed states. The method extends to other Zeeman sublevels and can be employed in a range of atomic clock schemes, atom interferometers, and other experiments using dressed atoms.

Myocardial perfusion in patients with suspected coronary artery disease: comparison between 320-MDCT and rubidium-82 PET.

PubMed

Dantas, Roberto Nery; Assuncao, Antonildes Nascimento; Marques, Ismar Aguiar; Fahel, Mateus Guimaraes; Nomura, Cesar Higa; Avila, Luiz Francisco Rodrigues; Giorgi, Maria Clementina Pinto; Soares, Jose; Meneghetti, Jose Claudio; Parga, Jose Rodrigues

2018-06-01

Despite advances in non-invasive myocardial perfusion imaging (MPI) evaluation, computed tomography (CT) multiphase MPI protocols have not yet been compared with the highly accurate rubidium-82 positron emission tomography ( 82 RbPET) MPI. Thus, this study aimed to evaluate agreement between 82 RbPET and 320-detector row CT (320-CT) MPI using a multiphase protocol in suspected CAD patients. Forty-four patients referred for MPI evaluation were prospectively enrolled and underwent dipyridamole stress 82 RbPET and multiphase 320-CT MPI (five consecutive volumetric acquisitions during stress). Statistical analyses were performed using the R software. There was high agreement for recognizing summed stress scores ≥ 4 (kappa 0.77, 95% CI 0.55-0.98, p < 0.001) and moderate for detecting SDS ≥ 2 (kappa 0.51, 95% CI 0.23-0.80, p < 0.001). In a per segment analysis, agreement was high for the presence of perfusion defects during stress and rest (kappa 0.75 and 0.82, respectively) and was moderate for impairment severity (kappa 0.58 and 0.65, respectively). The 320-CT protocol was safe, with low radiation burden (9.3 ± 2.4 mSv). There was a significant agreement between dipyridamole stress 320-CT MPI and 82 RbPET MPI in the evaluation of suspected CAD patients of intermediate risk. The multiphase 320-CT MPI protocol was feasible, diagnostic and with relatively low radiation exposure. • Rubidium-82 PET and 320-MDCT can perform MPI studies for CAD investigation. • There is high agreement between rubidium-82 PET and 320-MDCT for MPI assessment. • Multiphase CT perfusion protocols are feasible and with low radiation. • Multiphase CT perfusion protocols can identify image artefacts.

Optimal Adenosine Stress for Maximum Stress Perfusion, Coronary Flow Reserve, and Pixel Distribution of Coronary Flow Capacity by Kolmogorov-Smirnov Analysis.

PubMed

Kitkungvan, Danai; Lai, Dejian; Zhu, Hongjian; Roby, Amanda E; Johnson, Nils P; Steptoe, Derek D; Patel, Monica B; Kirkeeide, Richard; Gould, K Lance

2017-02-01

Different adenosine stress imaging protocols have not been systemically validated for absolute myocardial perfusion and coronary flow reserve (CFR) by positron emission tomography, where submaximal stress precludes assessing physiological severity of coronary artery disease. In 127 volunteers, serial rest-stress positron emission tomography scans using rubidium-82 with various adenosine infusion protocols identified (1) the protocol with maximum stress perfusion and CFR, (2) test-retest precision in same subject, (3) stress perfusion and CFR after adenosine compared with dipyridamole, (4) heterogeneity of coronary flow capacity combining stress perfusion and CFR, and (5) potential relevance for patients with risk factors or coronary artery disease. The adenosine 6-minute infusion with rubidium-82 injection at 3 minutes caused CFR that was significantly 15.7% higher than the 4-minute adenosine infusion with rubidium-82 injection at 2 minutes and significantly more homogeneous by Kolmogorov-Smirnov analysis for histograms of 1344 pixel range of perfusion in paired positron emission tomographies. In a coronary artery disease cohort separate from volunteers of this study, compared with the 3/6-minute protocol, the 2/4-minute adenosine protocol would potentially have changed 332 of 1732 (19%) positron emission tomographies at low-risk physiological severity CFR ≥2.3 to CFR <2.0, thereby implying high-risk quantitative severity potentially appropriate for interventions but because of suboptimal stress of the 2/4 protocol in some patients. The 6-minute adenosine infusion with rubidium-82 activation at 3 minutes produced CFR that averaged 15.7% higher than that in the 2/4-minute protocol, thereby potentially providing essential information for personalized management in some patients. © 2017 American Heart Association, Inc.

Observing and preventing rubidium runaway in a direct-infusion xenon-spin hyperpolarizer optimized for high-resolution hyper-CEST (chemical exchange saturation transfer using hyperpolarized nuclei) NMR.

PubMed

Witte, C; Kunth, M; Rossella, F; Schröder, L

2014-02-28

Xenon is well known to undergo host-guest interactions with proteins and synthetic molecules. As xenon can also be hyperpolarized by spin exchange optical pumping, allowing the investigation of highly dilute systems, it makes an ideal nuclear magnetic resonance probe for such host molecules. The utility of xenon as a probe can be further improved using Chemical Exchange Saturation Transfer using hyperpolarized nuclei (Hyper-CEST), but for highly accurate experiments requires a polarizer and xenon infusion system optimized for such measurements. We present the design of a hyperpolarizer and xenon infusion system specifically designed to meet the requirements of Hyper-CEST measurements. One key element of this design is preventing rubidium runaway, a chain reaction induced by laser heating that prevents efficient utilization of high photon densities. Using thermocouples positioned along the pumping cell we identify the sources of heating and conditions for rubidium runaway to occur. We then demonstrate the effectiveness of actively cooling the optical cell to prevent rubidium runaway in a compact setup. This results in a 2-3-fold higher polarization than without cooling, allowing us to achieve a polarization of 25% at continuous flow rates of 9 ml/min of (129)Xe. The simplicity of this design also allows it to be retrofitted to many existing polarizers. Combined with a direction infusion system that reduces shot-to-shot noise down to 0.56% we have captured Hyper-CEST spectra in unprecedented detail, allowing us to completely resolve peaks separated by just 1.62 ppm. Due to its high polarization and excellent stability, our design allows the comparison of underlying theories of host-guest systems with experiment at low concentrations, something extremely difficult with previous polarizers.

Estimation of chirp rates of music-adapted prolate spheroidal atoms using reassignment

NASA Astrophysics Data System (ADS)

Mesz, Bruno; Serrano, Eduardo

2007-09-01

We introduce a modified Matching Pursuit algorithm for estimating frequency and frequency slope of FM-modulated music signals. The use of Matching Pursuit with constant frequency atoms provides coarse estimates which could be improved with chirped atoms, more suited in principle to this kind of signals. Application of the reassignment method is suggested by its good localization properties for chirps. We start considering a family of atoms generated by modulation and scaling of a prolate spheroidal wave function. These functions are concentrated in frequency on intervals of a semitone centered at the frequencies of the well-tempered scale. At each stage of the pursuit, we search the atom most correlated with the signal. We then consider the spectral peaks at each frame of the spectrogram and calculate a modified frequency and frequency slope using the derivatives of the reassignment operators; this is then used to estimate the parameters of a cubic interpolation polynomial that models local pitch fluctuations. We apply the method both to synthetic and music signals.

Polarization insensitive frequency conversion for an atom-photon entanglement distribution via a telecom network.

PubMed

Ikuta, Rikizo; Kobayashi, Toshiki; Kawakami, Tetsuo; Miki, Shigehito; Yabuno, Masahiro; Yamashita, Taro; Terai, Hirotaka; Koashi, Masato; Mukai, Tetsuya; Yamamoto, Takashi; Imoto, Nobuyuki

2018-05-21

Long-lifetime quantum storages accessible to the telecom photonic infrastructure are essential to long-distance quantum communication. Atomic quantum storages have achieved subsecond storage time corresponding to 1000 km transmission time for a telecom photon through a quantum repeater algorithm. However, the telecom photon cannot be directly interfaced to typical atomic storages. Solid-state quantum frequency conversions fill this wavelength gap. Here we report on the experimental demonstration of a polarization-insensitive solid-state quantum frequency conversion to a telecom photon from a short-wavelength photon entangled with an atomic ensemble. Atom-photon entanglement has been generated with a Rb atomic ensemble and the photon has been translated to telecom range while retaining the entanglement by our nonlinear-crystal-based frequency converter in a Sagnac interferometer.

Atomic clocks for geodesy.

PubMed

Mehlstäubler, Tanja E; Grosche, Gesine; Lisdat, Christian; Schmidt, Piet O; Denker, Heiner

2018-06-01

We review experimental progress on optical atomic clocks and frequency transfer, and consider the prospects of using these technologies for geodetic measurements. Today, optical atomic frequency standards have reached relative frequency inaccuracies below 10 -17 , opening new fields of fundamental and applied research. The dependence of atomic frequencies on the gravitational potential makes atomic clocks ideal candidates for the search for deviations in the predictions of Einstein's general relativity, tests of modern unifying theories and the development of new gravity field sensors. In this review, we introduce the concepts of optical atomic clocks and present the status of international clock development and comparison. Besides further improvement in stability and accuracy of today's best clocks, a large effort is put into increasing the reliability and technological readiness for applications outside of specialized laboratories with compact, portable devices. With relative frequency uncertainties of 10 -18 , comparisons of optical frequency standards are foreseen to contribute together with satellite and terrestrial data to the precise determination of fundamental height reference systems in geodesy with a resolution at the cm-level. The long-term stability of atomic standards will deliver excellent long-term height references for geodetic measurements and for the modelling and understanding of our Earth.

Atomic fountain clock with very high frequency stability employing a pulse-tube-cryocooled sapphire oscillator.

PubMed

Takamizawa, Akifumi; Yanagimachi, Shinya; Tanabe, Takehiko; Hagimoto, Ken; Hirano, Iku; Watabe, Ken-ichi; Ikegami, Takeshi; Hartnett, John G

2014-09-01

The frequency stability of an atomic fountain clock was significantly improved by employing an ultra-stable local oscillator and increasing the number of atoms detected after the Ramsey interrogation, resulting in a measured Allan deviation of 8.3 × 10(-14)τ(-1/2)). A cryogenic sapphire oscillator using an ultra-low-vibration pulse-tube cryocooler and cryostat, without the need for refilling with liquid helium, was applied as a local oscillator and a frequency reference. High atom number was achieved by the high power of the cooling laser beams and optical pumping to the Zeeman sublevel m(F) = 0 employed for a frequency measurement, although vapor-loaded optical molasses with the simple (001) configuration was used for the atomic fountain clock. The resulting stability is not limited by the Dick effect as it is when a BVA quartz oscillator is used as the local oscillator. The stability reached the quantum projection noise limit to within 11%. Using a combination of a cryocooled sapphire oscillator and techniques to enhance the atom number, the frequency stability of any atomic fountain clock, already established as primary frequency standard, may be improved without opening its vacuum chamber.

Atomic clocks for geodesy

NASA Astrophysics Data System (ADS)

Mehlstäubler, Tanja E.; Grosche, Gesine; Lisdat, Christian; Schmidt, Piet O.; Denker, Heiner

2018-06-01

We review experimental progress on optical atomic clocks and frequency transfer, and consider the prospects of using these technologies for geodetic measurements. Today, optical atomic frequency standards have reached relative frequency inaccuracies below 10‑17, opening new fields of fundamental and applied research. The dependence of atomic frequencies on the gravitational potential makes atomic clocks ideal candidates for the search for deviations in the predictions of Einstein’s general relativity, tests of modern unifying theories and the development of new gravity field sensors. In this review, we introduce the concepts of optical atomic clocks and present the status of international clock development and comparison. Besides further improvement in stability and accuracy of today’s best clocks, a large effort is put into increasing the reliability and technological readiness for applications outside of specialized laboratories with compact, portable devices. With relative frequency uncertainties of 10‑18, comparisons of optical frequency standards are foreseen to contribute together with satellite and terrestrial data to the precise determination of fundamental height reference systems in geodesy with a resolution at the cm-level. The long-term stability of atomic standards will deliver excellent long-term height references for geodetic measurements and for the modelling and understanding of our Earth.

Primary Atomic Frequency Standards at NIST

PubMed Central

Sullivan, D. B.; Bergquist, J. C.; Bollinger, J. J.; Drullinger, R. E.; Itano, W. M.; Jefferts, S. R.; Lee, W. D.; Meekhof, D.; Parker, T. E.; Walls, F. L.; Wineland, D. J.

2001-01-01

The development of atomic frequency standards at NIST is discussed and three of the key frequency-standard technologies of the current era are described. For each of these technologies, the most recent NIST implementation of the particular type of standard is described in greater detail. The best relative standard uncertainty achieved to date for a NIST frequency standard is 1.5×10−15. The uncertainties of the most recent NIST standards are displayed relative to the uncertainties of atomic frequency standards of several other countries. PMID:27500017

High Atom Number in Microsized Atom Traps

DTIC Science & Technology

2015-12-14

forces on the order of (hbar)(k) (Omega), where Omega is the laser Rabi frequency. We have observed behavior compatible with bichromatic slowing and... Rabi frequency. We have observed behavior compatible with bichromatic slowing and cooling of some atoms in atomic beam. Results were presented at the

Image cloning beyond diffraction based on coherent population trapping in a hot rubidium vapor.

PubMed

Ding, Dong-Sheng; Zhou, Zhi-Yuan; Shi, Bao-Sen

2014-01-15

Following recent theoretical predictions, we report on an experimental realization of image cloning beyond usual diffraction, through the coherent population trapping (CPT) effect in a hot rubidium vapor. In our experiment, an alphabet letter image was transferred from a coupling field to a probe field, based on the CPT effect. Furthermore, we demonstrate that the cloned probe field carrying the image is transmitted without the usual diffraction. To our best knowledge, this is the first experimental report about image cloning beyond diffraction. We believe this mechanism, based on CPT, has definite and important applications in image metrology, image processing, and biomedical imaging.

[Dependence of ion transport across the plasma membrane on cell culture density. II. Active and passive cation transport during the growth of L cell cultures].

PubMed

Marakhova, I I; Sal'nikov, K V; Vinogradova, T A

1985-10-01

Rubidium and lithium influxes as well as intracellular potassium and sodium contents were investigated in L cells during the culture growth. In sparse culture over the cell densities 0.5-3 X 10(4) cells/cm2 ouabain-sensitive rubidium influx is small and ouabain-resistant lithium influx in high. With the increase in culture density up to 4-5 X 10(4) cells/cm2 the active rubidium influx, mediated by ouabain-sensitive component, is enhanced, and ion "leakage" tested by lithium influx is diminished. Simultaneously with the exponential growth of culture the intracellular potassium content is increased and the intracellular sodium content is decreased resulting in the higher K/Na ratio in cell. During the further transition to dense culture and in stationary state (10-17 X 10(4) cells/cm2) the sodium content and lithium influx do not change significantly, but the potassium content is decreased. The decrease in intracellular potassium is correlated with that in the portion of cells in S-phase from 27-30 to 12%. Thus, in transformed cells the density-dependent alterations in membrane cation transport are observed.

Major- and Trace-Element Concentrations in Soils from Two Geochemical Surveys (1972 and 2005) of the Denver, Colorado, Metropolitan Area

USGS Publications Warehouse

Kilburn, James E.; Smith, David B.; Closs, L. Graham; Smith, Steven M.

2007-01-01

Introduction This report contains major- and trace-element concentration data for soil samples collected in 1972 and 2005 from the Denver, Colorado, metropolitan area. A total of 405 sites were sampled in the 1972 study from an area approximately bounded by the suburbs of Golden, Thornton, Aurora, and Littleton to the west, north, east, and south, respectively. This data set included 34 duplicate samples collected in the immediate vicinity of the primary sample. In 2005, a total of 464 sites together with 34 duplicates were sampled from the same approximate localities sampled in 1972 as well as additional sites in east Aurora and the area surrounding the Rocky Mountain Arsenal. Sample density for both surveys was on the order of 1 site per square mile. At each site, sample material was collected from a depth of 0-5 inches. Each sample collected was analyzed for near-total major- and trace-element composition by the following methods: (1) inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) for aluminum, antimony, arsenic, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chromium, cobalt, copper, gallium, indium, iron, lanthanum, lead, lithium, magnesium, manganese, molybdenum, nickel, niobium, phosphorus, potassium, rubidium, scandium, silver, sodium, strontium, sulfur, tellurium, thallium, thorium, tin, titanium, tungsten, uranium, vanadium, yttrium, and zinc; and (2) hydride generation-atomic absorption spectrometry for selenium. The samples collected in 2005 were also analyzed by a cold vapor-atomic absorption method for mercury. This report makes available the analytical results of these studies.

Metastability and avalanche dynamics in strongly correlated gases with long-range interactions

NASA Astrophysics Data System (ADS)

Hruby, Lorenz; Dogra, Nishant; Landini, Manuele; Donner, Tobias; Esslinger, Tilman

2018-03-01

We experimentally study the stability of a bosonic Mott insulator against the formation of a density wave induced by long-range interactions and characterize the intrinsic dynamics between these two states. The Mott insulator is created in a quantum degenerate gas of 87-Rubidium atoms, trapped in a 3D optical lattice. The gas is located inside and globally coupled to an optical cavity. This causes interactions of global range, mediated by photons dispersively scattered between a transverse lattice and the cavity. The scattering comes with an atomic density modulation, which is measured by the photon flux leaking from the cavity. We initialize the system in a Mott-insulating state and then rapidly increase the global coupling strength. We observe that the system falls into either of two distinct final states. One is characterized by a low photon flux, signaling a Mott insulator, and the other is characterized by a high photon flux, which we associate with a density wave. Ramping the global coupling slowly, we observe a hysteresis loop between the two states—a further signature of metastability. A comparison with a theoretical model confirms that the metastability originates in the competition between short- and global-range interactions. From the increasing photon flux monitored during the switching process, we find that several thousand atoms tunnel to a neighboring site on the timescale of the single-particle dynamics. We argue that a density modulation, initially forming in the compressible surface of the trapped gas, triggers an avalanche tunneling process in the Mott-insulating region.

Initial atomic coherences and Ramsey frequency pulling in fountain clocks

NASA Astrophysics Data System (ADS)

Gerginov, Vladislav; Nemitz, Nils; Weyers, Stefan

2014-09-01

In the uncertainty budget of primary atomic cesium fountain clocks, evaluations of frequency-pulling shifts of the hyperfine clock transition caused by unintentional excitation of its nearby transitions (Rabi and Ramsey pulling) have been based so far on an approach developed for cesium beam clocks. We re-evaluate this type of frequency pulling in fountain clocks and pay particular attention to the effect of initial coherent atomic states. We find significantly enhanced frequency shifts caused by Ramsey pulling due to sublevel population imbalance and corresponding coherences within the state-selected hyperfine component of the initial atom ground state. Such shifts are experimentally investigated in an atomic fountain clock and quantitative agreement with the predictions of the model is demonstrated.

Resonant difference-frequency atomic force ultrasonic microscope

NASA Technical Reports Server (NTRS)

Cantrell, John H. (Inventor); Cantrell, Sean A. (Inventor)

2010-01-01

A scanning probe microscope and methodology called resonant difference-frequency atomic force ultrasonic microscopy (RDF-AFUM), employs an ultrasonic wave launched from the bottom of a sample while the cantilever of an atomic force microscope, driven at a frequency differing from the ultrasonic frequency by one of the contact resonance frequencies of the cantilever, engages the sample top surface. The nonlinear mixing of the oscillating cantilever and the ultrasonic wave in the region defined by the cantilever tip-sample surface interaction force generates difference-frequency oscillations at the cantilever contact resonance. The resonance-enhanced difference-frequency signals are used to create images of nanoscale near-surface and subsurface features.

Mean-field scaling of the superfluid to Mott insulator transition in a 2D optical superlattice.

NASA Astrophysics Data System (ADS)

Okano, Masayuki; Thomas, Claire; Barter, Thomas; Leung, Tsz-Him; Jo, Gyu-Boong; Guzman, Jennie; Kimchi, Itamar; Vishwanath, Ashvin; Stamper-Kurn, Dan

2017-04-01

Quantum gases within optical lattices provide a nearly ideal experimental representation of the Bose-Hubbard model. The mean-field treatment of this model predicts properties of non-zero temperature lattice-trapped gasses to be insensitive to the specific lattice geometry once system energies are scaled by the lattice coordination number z. We examine an ultracold Bose gas of rubidium atoms prepared within a two-dimensional lattice whose geometry can be tuned between two configurations, triangular and kagome, for which z varies from six to four, respectively. Measurements of the coherent fraction of the gas thereby provide a quantitative test of the mean-field scaling prediction. We observe the suppression of superfluidity upon decreasing z, and find our results to be consistent with the predicted mean-field scaling. These optical lattice systems can offer a way to study paradigmatic solid-state phenomena in highly controlled crystal structures. This work was supported by the NSF and by the Army Research Office with funding from the DARPA OLE program.

Dynamics of Superradiant Lasers

NASA Astrophysics Data System (ADS)

Thompson, James

2014-05-01

A superradiant laser has been shown to operate with less than one photon on average inside of the optical cavity. In this regime, almost all of the phase information of the laser is stored in the atoms rather than the cavity field. As a result, the laser's phase is highly insensitive to both technical and fundamental thermal cavity mirror vibrations. This vibration noise presently limits the coherence of the best lasers as well as the precision of the optical lattice clocks that these lasers interrogate. We have explored the physics of superradiant lasers utilizing Raman transitions between hyperfine states in rubidium to mimic narrow optical transitions. In this talk, we will discuss the amplitude stability of our superradiant Raman laser, and the dynamics of phase synchronization in our system. We will also consider the prospects for future superradiant lasers that would lase on the same highly-forbidden transitions used in optical lattice clocks. We acknowledge support from DARPA QUASAR, ARO, NIST, and the NSF PFC.

Improvement of Frequency Locking Algorithm for Atomic Frequency Standards

NASA Astrophysics Data System (ADS)

Park, Young-Ho; Kang, Hoonsoo; Heyong Lee, Soo; Eon Park, Sang; Lee, Jong Koo; Lee, Ho Seong; Kwon, Taeg Yong

2010-09-01

The authors describe a novel method of frequency locking algorithm for atomic frequency standards. The new algorithm for locking the microwave frequency to the Ramsey resonance is compared with the old one that had been employed in the cesium atomic beam frequency standards such as NIST-7 and KRISS-1. Numerical simulations for testing the performance of the algorithm show that the new method has a noise filtering performance superior to the old one by a factor of 1.2 for the flicker signal noise and 1.4 for random-walk signal noise. The new algorithm can readily be used to enhance the frequency stability for a digital servo employing the slow square wave frequency modulation.

Deterministically swapping frequency-bin entanglement from photon-photon to atom-photon hybrid systems

NASA Astrophysics Data System (ADS)

Ou, Bao-Quan; Liu, Chang; Sun, Yuan; Chen, Ping-Xing

2018-02-01

Inspired by the recent developments of the research on the atom-photon quantum interface and energy-time entanglement between single-photon pulses, we are motivated to study the deterministic protocol for the frequency-bin entanglement of the atom-photon hybrid system, which is analogous to the frequency-bin entanglement between single-photon pulses. We show that such entanglement arises naturally in considering the interaction between a frequency-bin entangled single-photon pulse pair and a single atom coupled to an optical cavity, via straightforward atom-photon phase gate operations. Its anticipated properties and preliminary examples of its potential application in quantum networking are also demonstrated. Moreover, we construct a specific quantum entanglement witness tool to detect such extended frequency-bin entanglement from a reasonably general set of separable states, and prove its capability theoretically. We focus on the energy-time considerations throughout the analysis.

Influence of excitation frequency on the metastable atoms and electron energy distribution function in a capacitively coupled argon discharge

NASA Astrophysics Data System (ADS)

Sharma, S.; Sirse, N.; Turner, M. M.; Ellingboe, A. R.

2018-06-01

One-dimensional particle-in-cell simulation is used to simulate the capacitively coupled argon plasma for a range of excitation frequency from 13.56 MHz to 100 MHz. The argon chemistry set can, selectively, include two metastable levels enabling multi-step ionization and metastable pooling. The results show that the plasma density decreases when metastable atoms are included with higher discrepancy at a higher excitation frequency. The contribution of multistep ionization to the overall density increases with the excitation frequency. The electron temperature increases with the inclusion of metastable atoms and decreases with the excitation frequency. At a lower excitation frequency, the density of Ar** (3p5 4p, 13.1 eV) is higher than that of Ar* (3p5 4s, 11.6 eV), whereas at higher excitation frequencies, the Ar* (3p5 4s, 11.6 eV) is the dominant metastable atom. The metastable and electron temperature profile evolve from a parabolic profile at a lower excitation frequency to a saddle type profile at a higher excitation frequency. With metastable, the electron energy distribution function (EEDF) changes its shape from Druyvesteyn type, at a low excitation frequency, to bi-Maxwellian, at a high frequency plasma excitation; however, a three-temperature EEDF is observed without metastable atoms.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oh, E.; Horne, R. A.; Sackett, C. A., E-mail: sackett@virginia.edu

Atom interferometry experiments rely on the ability to obtain a stable signal that corresponds to an atomic phase. For interferometers that use laser beams to manipulate the atoms, noise in the lasers can lead to errors in the atomic measurement. In particular, it is often necessary to actively stabilize the optical phase between two frequency components of the beams. Typically this is achieved using a time-domain measurement of a beat note between the two frequencies. This becomes challenging when the frequency difference is small and the phase measurement must be made quickly. The method presented here instead uses a spatialmore » interference detection to rapidly measure the optical phase for arbitrary frequency differences. A feedback system operating at a bandwidth of about 10 MHz could then correct the phase in about 3 μs. This time is short enough that the phase correction could be applied at the start of a laser pulse without appreciably degrading the fidelity of the atom interferometer operation. The phase stabilization system was demonstrated in a simple atom interferometer measurement of the {sup 87}Rb recoil frequency.« less

AWAKE readiness for the study of the seeded self-modulation of a 400 GeV proton bunch

NASA Astrophysics Data System (ADS)

Muggli, P.; Adli, E.; Apsimon, R.; Asmus, F.; Baartman, R.; Bachmann, A.-M.; Barros Marin, M.; Batsch, F.; Bauche, J.; Berglyd Olsen, V. K.; Bernardini, M.; Biskup, B.; Blanco Vinuela, E.; Boccardi, A.; Bogey, T.; Bohl, T.; Bracco, C.; Braunmuller, F.; Burger, S.; Burt, G.; Bustamante, S.; Buttenschön, B.; Butterworth, A.; Caldwell, A.; Cascella, M.; Chevallay, E.; Chung, M.; Damerau, H.; Deacon, L.; Dexter, A.; Dirksen, P.; Doebert, S.; Farmer, J.; Fedosseev, V.; Feniet, T.; Fior, G.; Fiorito, R.; Fonseca, R.; Friebel, F.; Gander, P.; Gessner, S.; Gorgisyan, I.; Gorn, A. A.; Grulke, O.; Gschwendtner, E.; Guerrero, A.; Hansen, J.; Hessler, C.; Hofle, W.; Holloway, J.; Hüther, M.; Ibison, M.; Islam, M. R.; Jensen, L.; Jolly, S.; Kasim, M.; Keeble, F.; Kim, S.-Y.; Kraus, F.; Lasheen, A.; Lefevre, T.; LeGodec, G.; Li, Y.; Liu, S.; Lopes, N.; Lotov, K. V.; Martyanov, M.; Mazzoni, S.; Medina Godoy, D.; Mete, O.; Minakov, V. A.; Mompo, R.; Moody, J.; Moreira, M. T.; Mitchell, J.; Mutin, C.; Norreys, P.; Öz, E.; Ozturk, E.; Pauw, W.; Pardons, A.; Pasquino, C.; Pepitone, K.; Petrenko, A.; Pitmann, S.; Plyushchev, G.; Pukhov, A.; Rieger, K.; Ruhl, H.; Schmidt, J.; Shalimova, I. A.; Shaposhnikova, E.; Sherwood, P.; Silva, L.; Sosedkin, A. P.; Speroni, R.; Spitsyn, R. I.; Szczurek, K.; Thomas, J.; Tuev, P. V.; Turner, M.; Verzilov, V.; Vieira, J.; Vincke, H.; Welsch, C. P.; Williamson, B.; Wing, M.; Xia, G.; Zhang, H.; AWAKE Collaboration

2018-01-01

AWAKE is a proton-driven plasma wakefield acceleration experiment. We show that the experimental setup briefly described here is ready for systematic study of the seeded self-modulation of the 400 GeV proton bunch in the 10 m long rubidium plasma with density adjustable from 1 to 10× {10}14 cm-3. We show that the short laser pulse used for ionization of the rubidium vapor propagates all the way along the column, suggesting full ionization of the vapor. We show that ionization occurs along the proton bunch, at the laser time and that the plasma that follows affects the proton bunch.

A single-mode external cavity diode laser using an intra-cavity atomic Faraday filter with short-term linewidth <400 kHz and long-term stability of <1 MHz.

PubMed

Keaveney, James; Hamlyn, William J; Adams, Charles S; Hughes, Ifan G

2016-09-01

We report on the development of a diode laser system - the "Faraday laser" - using an atomic Faraday filter as the frequency-selective element. In contrast to typical external-cavity diode laser systems which offer tunable output frequency but require additional control systems in order to achieve a stable output frequency, our system only lases at a single frequency, set by the peak transmission frequency of the internal atomic Faraday filter. Our system has both short-term and long-term stability of less than 1 MHz, which is less than the natural linewidth of alkali-atomic D-lines, making similar systems suitable for use as a "turn-key" solution for laser-cooling experiments.

Optically-pumped spin-exchange polarized electron source

NASA Astrophysics Data System (ADS)

Pirbhai, Munir Hussein

Polarized electron beams are an indispensable probe of spin-dependent phenomena in fields of atomic and molecular physics, magnetism and biophysics. While their uses have become widespread, the standard source based on negative electron affinity gallium arsenide (GaAs) remains technically complicated. This has hindered progress on many experiments involving spin-polarized electrons, especially those using target gas loads, which tend to adversely affect the performance of GaAs sources. A robust system based on an alternative way to make polarized electron beams has been devised in this study, which builds on previous work done in our lab. It involves spin-exchange collisions between free, unpolarized electrons and oriented rubidium atoms in the presence of a quenching gas. This system has less stringent vacuum requirements than those of GaAs sources, and is capable of operating in background pressures of ~1mTorr. Beams with ~24% polarization and 4μA of current have been recorded, which is comparable to the performance obtained with the earlier version built in our lab. The present system is however not as unstable as in the previous work, and has the potential to be developed into a "turn-key" source of polarized electron beams. It has also allowed us to undertake a study to find factors which affect the beam polarization in this scheme of producing polarized electrons. Such knowledge will help us to design better optically-pumped spin-exchange polarized electron sources.

Detecting an atomic clock frequency anomaly using an adaptive Kalman filter algorithm

NASA Astrophysics Data System (ADS)

Song, Huijie; Dong, Shaowu; Wu, Wenjun; Jiang, Meng; Wang, Weixiong

2018-06-01

The abnormal frequencies of an atomic clock mainly include frequency jump and frequency drift jump. Atomic clock frequency anomaly detection is a key technique in time-keeping. The Kalman filter algorithm, as a linear optimal algorithm, has been widely used in real-time detection for abnormal frequency. In order to obtain an optimal state estimation, the observation model and dynamic model of the Kalman filter algorithm should satisfy Gaussian white noise conditions. The detection performance is degraded if anomalies affect the observation model or dynamic model. The idea of the adaptive Kalman filter algorithm, applied to clock frequency anomaly detection, uses the residuals given by the prediction for building ‘an adaptive factor’ the prediction state covariance matrix is real-time corrected by the adaptive factor. The results show that the model error is reduced and the detection performance is improved. The effectiveness of the algorithm is verified by the frequency jump simulation, the frequency drift jump simulation and the measured data of the atomic clock by using the chi-square test.

Entanglement of atomic qubits using an optical frequency comb.

PubMed

Hayes, D; Matsukevich, D N; Maunz, P; Hucul, D; Quraishi, Q; Olmschenk, S; Campbell, W; Mizrahi, J; Senko, C; Monroe, C

2010-04-09

We demonstrate the use of an optical frequency comb to coherently control and entangle atomic qubits. A train of off-resonant ultrafast laser pulses is used to efficiently and coherently transfer population between electronic and vibrational states of trapped atomic ions and implement an entangling quantum logic gate with high fidelity. This technique can be extended to the high field regime where operations can be performed faster than the trap frequency. This general approach can be applied to more complex quantum systems, such as large collections of interacting atoms or molecules.

Repetitive Interrogation of 2-Level Quantum Systems

NASA Technical Reports Server (NTRS)

Prestage, John D.; Chung, Sang K.

2010-01-01

Trapped ion clocks derive information from a reference atomic transition by repetitive interrogations of the same quantum system, either a single ion or ionized gas of many millions of ions. Atomic beam frequency standards, by contrast, measure reference atomic transitions in a continuously replenished "flow through" configuration where initial ensemble atomic coherence is zero. We will describe some issues and problems that can arise when atomic state selection and preparation of the quantum atomic system is not completed, that is, optical pumping has not fully relaxed the coherence and also not fully transferred atoms to the initial state. We present a simple two-level density matrix analysis showing how frequency shifts during the state-selection process can cause frequency shifts of the measured clock transition. Such considerations are very important when a low intensity lamp light source is used for state selection, where there is relatively weak relaxation and re-pumping of ions to an initial state and much weaker 'environmental' relaxation of the atomic coherence set-up in the atomic sample.

Picosecond-precision multichannel autonomous time and frequency counter

NASA Astrophysics Data System (ADS)

Szplet, R.; Kwiatkowski, P.; RóŻyc, K.; Jachna, Z.; Sondej, T.

2017-12-01

This paper presents the design, implementation, and test results of a multichannel time interval and frequency counter developed as a desktop instrument. The counter contains four main functional modules for (1) performing precise measurements, (2) controlling and fast data processing, (3) low-noise power suppling, and (4) supplying a stable reference clock (optional rubidium standard). A fundamental for the counter, the time interval measurement is based on time stamping combined with a period counting and in-period two-stage time interpolation that allows us to achieve wide measurement range (above 1 h), high precision (even better than 4.5 ps), and high measurement speed (up to 91.2 × 106 timestamps/s). The frequency is measured up to 3.0 GHz with the use of the reciprocal method. Wide functionality of the counter includes also the evaluation of frequency stability of clocks and oscillators (Allan deviation) and phase variation (time interval error, maximum time interval error, time deviation). The 8-channel measurement module is based on a field programmable gate array device, while the control unit involves a microcontroller with a high performance ARM-Cortex core. An efficient and user-friendly control of the counter is provided either locally, through the built-in keypad or/and color touch panel, or remotely, with the aid of USB, Ethernet, RS232C, or RS485 interfaces.

Picosecond-precision multichannel autonomous time and frequency counter.

PubMed

Szplet, R; Kwiatkowski, P; Różyc, K; Jachna, Z; Sondej, T

2017-12-01

This paper presents the design, implementation, and test results of a multichannel time interval and frequency counter developed as a desktop instrument. The counter contains four main functional modules for (1) performing precise measurements, (2) controlling and fast data processing, (3) low-noise power suppling, and (4) supplying a stable reference clock (optional rubidium standard). A fundamental for the counter, the time interval measurement is based on time stamping combined with a period counting and in-period two-stage time interpolation that allows us to achieve wide measurement range (above 1 h), high precision (even better than 4.5 ps), and high measurement speed (up to 91.2 × 10 6 timestamps/s). The frequency is measured up to 3.0 GHz with the use of the reciprocal method. Wide functionality of the counter includes also the evaluation of frequency stability of clocks and oscillators (Allan deviation) and phase variation (time interval error, maximum time interval error, time deviation). The 8-channel measurement module is based on a field programmable gate array device, while the control unit involves a microcontroller with a high performance ARM-Cortex core. An efficient and user-friendly control of the counter is provided either locally, through the built-in keypad or/and color touch panel, or remotely, with the aid of USB, Ethernet, RS232C, or RS485 interfaces.

Experimental implementation of a nonlinear beamsplitter based on a phase-sensitive parametric amplifier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fang, Yami; Feng, Jingliang; Cao, Leiming

2016-03-28

Beamsplitters have played an important role in quantum optics experiments. They are often used to split and combine two beams, especially in the construct of an interferometer. In this letter, we experimentally implement a nonlinear beamsplitter using a phase-sensitive parametric amplifier, which is based on four-wave mixing in hot rubidium vapor. Here we show that, despite the different frequencies of the two input beams, the output ports of the nonlinear beamsplitter exhibit interference phenomena. We make measurements of the interference fringe visibility and study how various parameters, such as the intensity gain of the amplifier, the intensity ratio of themore » two input beams, and the one and two photon detunings, affect the behavior of the nonlinear beamsplitter. It may find potential applications in quantum metrology and quantum information processing.« less

Probing the Quantum States of a Single Atom Transistor at Microwave Frequencies.

PubMed

Tettamanzi, Giuseppe Carlo; Hile, Samuel James; House, Matthew Gregory; Fuechsle, Martin; Rogge, Sven; Simmons, Michelle Y

2017-03-28

The ability to apply gigahertz frequencies to control the quantum state of a single P atom is an essential requirement for the fast gate pulsing needed for qubit control in donor-based silicon quantum computation. Here, we demonstrate this with nanosecond accuracy in an all epitaxial single atom transistor by applying excitation signals at frequencies up to ≈13 GHz to heavily phosphorus-doped silicon leads. These measurements allow the differentiation between the excited states of the single atom and the density of states in the one-dimensional leads. Our pulse spectroscopy experiments confirm the presence of an excited state at an energy ≈9 meV, consistent with the first excited state of a single P donor in silicon. The relaxation rate of this first excited state to the ground state is estimated to be larger than 2.5 GHz, consistent with theoretical predictions. These results represent a systematic investigation of how an atomically precise single atom transistor device behaves under radio frequency excitations.

A Cesium fountain frequency standard: Preliminary results

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clairon, A.; Laurent, P.; Santarelli, G.

1994-12-31

Laser cooling of atoms has opened up new possibilities in the field of atomic frequency standards. A Cesium atomic fountain, first proposed by Zacharias in 1953, is now feasible: the atoms, first cooled by six laser beams, are launched upward using laser light, pass once through a microwave cavity, continue their ballistic flight and then fall through the same cavity. The long time between the two microwave interactions leads to a Ramsey resonance much narrower than in conventional Cs clocks using thermal atomic beams. The stability and accuracy of such a cesium fountain am very attractive. The use of diodemore » lasers to cool, launch and detect cesium atoms in a low cesium pressure cell allows the construction of a simple and reliable atomic fountain frequency standard. A fountain frequency standard is now in operation at LPTF. A Ramsey resonance as narrow as 0.8 Hz has been obtained. A few days of continuous operation are routinely obtained. In closed loop operation the fountain frequency standard is continuously monitored against a H maser allowing an evaluation of the accuracy of the device. The present short- term frequency stability is about 5.10{sup -13} {tau}{sup -1/2} limited only by the frequency noise of the microwave source. We intend to present a preliminary evaluation of this new standard with a discussion of the major systematic effects which determine the accuracy. The expected accuracy will be at 10-14 level. In addition, we will present a description of the whole design of the cesium fountain.« less

Renal function in sheep during infusion of alkali metal ions into the renal artery.

PubMed Central

Beal, A M; Harrison, F A

1975-01-01

1. The effect on renal function of 1 M solutions of LiCl, NaCl, KCl, RbCl and CsCl and 3 M-NaCl infused close-arterially to the kidney for 10 min at 0-7ml./min has been studied in nine experiments on four unilaterally nephrectomized sheep. The levels of flow, electrolyte concentration and electrolyte excretion in the urine were measured before, during and for 50 min after the infusions. 2. The infusion of 1-M-NaCl produced little change in urine flow and composition whereas 3 M-NaCl resulted in relatively small increases in urine flow and sodium excretion. 3. The infusion of lithium, potassium, rubidium and caesium resulted in marked increases in urine flow, urinary sodium concentration and excretion, urinary potassium excretion and osmolal clearance while the urinary potassium concentration decreased. 4. Changes in urine flow and urinary pH during the infusions of all the alkali ions except sodium were consistent with increased urinary bicarbonate excretion. 5. The osmolal clearance was increased by the infusion of lithium, potassium, rubidium and caesium, but equivalent increases in the rate of solutefree water reabsorption did not occur. 6. The infusion of caesium resulted in a depression of the glomerular filtration rate (G.F.R.) which was not observed when the other alkali ions were infused. 7. The effects of lithium, potassium and rubidium on urine flow and composition were rapid in onset and the residual effects on these ions, on cessation of infusion, were relatively short. The effects on caesium were slow in onset and prolonged in duration. 8. It was concluded that lithium, potassium, rubidium, and caesium altered urine flow and electrolyte excretion by acting upon common mechanisms which were predominantly intra-renal and located in the proximal segment of the nephron. PMID:236381

A polarization converting device for an interfering enhanced CPT atomic clock.

PubMed

Wang, Kewei; Tian, Yuan; Yin, Yi; Wang, Yuanchao; Gu, Sihong

2017-11-01

With interfering enhanced coherent population trapping (CPT) signals, a CPT atomic clock with improved frequency stability performance can be realized. We explore an optical device that converts single-polarized bichromatic light to left and right circularly polarized superposed bichromatic light to generate interfering enhanced CPT resonance with atoms. We have experimentally studied a tabletop CPT atomic clock apparatus with a microfabricated 87 Rb atomic chip-scale cell, and the study results show that it is promising to realize a compact CPT atomic clock, even a chip-scale CPT atomic clock through microfabrication, with improved frequency stability performance.

A polarization converting device for an interfering enhanced CPT atomic clock

NASA Astrophysics Data System (ADS)

Wang, Kewei; Tian, Yuan; Yin, Yi; Wang, Yuanchao; Gu, Sihong

2017-11-01

With interfering enhanced coherent population trapping (CPT) signals, a CPT atomic clock with improved frequency stability performance can be realized. We explore an optical device that converts single-polarized bichromatic light to left and right circularly polarized superposed bichromatic light to generate interfering enhanced CPT resonance with atoms. We have experimentally studied a tabletop CPT atomic clock apparatus with a microfabricated 87Rb atomic chip-scale cell, and the study results show that it is promising to realize a compact CPT atomic clock, even a chip-scale CPT atomic clock through microfabrication, with improved frequency stability performance.

Tunable meta-atom using liquid metal embedded in stretchable polymer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Peng; Yang, Siming; Wang, Qiugu

2015-07-07

Reconfigurable metamaterials have great potential to alleviate complications involved in using passive metamaterials to realize emerging electromagnetic functions, such as dynamical filtering, sensing, and cloaking. This paper presents a new type of tunable meta-atoms in the X-band frequency range (8–12 GHz) toward reconfigurable metamaterials. The meta-atom is made of all flexible materials compliant to the surface of an interaction object. It uses a liquid metal-based split-ring resonator as its core constituent embedded in a highly flexible elastomer. We demonstrate that simple mechanical stretching of the meta-atom can lead to the great flexibility in reconfiguring its resonance frequency continuously over moremore » than 70% of the X-band frequency range. The presented meta-atom technique provides a simple approach to dynamically tune response characteristics of metamaterials over a broad frequency range.« less

Graduate Student Support for Quantum Computing With Superconducting Charge States

DTIC Science & Technology

2005-08-31

cavity resonance frequency ωr, the atomic transition frequency Ω, and the strength of the atom- photon coupling g appearing in the Jaynes - Cummings ...the atom through the cavity. In the absence of damping, exact diagonalization of the Jaynes - Cumming Hamiltonian yields the excited eigen- states...cillating terms and omitting damping for the moment, 5 Eq. (16) reduces to the Jaynes - Cummings Hamiltonian (1) with Ω = EJ/~ and the vacuum Rabi frequency

Major- and trace-element concentrations in soils from two continental-scale transects of the United States and Canada

USGS Publications Warehouse

Smith, David B.; Cannon, William F.; Woodruff, Laurel G.; Garrett, Robert G.; Klassen, Rodney; Kilburn, James E.; Horton, John D.; King, Harley D.; Goldhaber, Martin B.; Morrison, Jean M.

2005-01-01

This report contains major- and trace-element concentration data for soil samples collected from 265 sites along two continental-scale transects in North America. One of the transects extends from northern Manitoba to the United States-Mexico border near El Paso, Tex. and consists of 105 sites. The other transect approximately follows the 38th parallel from the Pacific coast of the United States near San Francisco, Calif., to the Atlantic coast along the Maryland shore and consists of 160 sites. Sampling sites were defined by first dividing each transect into approximately 40-km segments. For each segment, a 1-km-wide latitudinal strip was randomly selected; within each strip, a potential sample site was selected from the most representative landscape within the most common soil type. At one in four sites, duplicate samples were collected 10 meters apart to estimate local spatial variability. At each site, up to four separate soil samples were collected as follows: (1) material from 0-5 cm depth; (2) O horizon, if present; (3) a composite of the A horizon; and (4) C horizon. Each sample collected was analyzed for total major- and trace-element composition by the following methods: (1) inductively coupled plasmamass spectrometry (ICP-MS) and inductively coupled plasma-atomic emission spectrometry (ICPAES) for aluminum, antimony, arsenic, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chromium, cobalt, copper, gallium, indium, iron, lanthanum, lead, lithium, magnesium, manganese, molybdenum, nickel, niobium, phosphorus, potassium, rubidium, scandium, silver, sodium, strontium, sulfur, tellurium, thallium, thorium, tin, titanium, tungsten, uranium, vanadium, yttrium, and zinc; (2) cold vapor- atomic absorption spectrometry for mercury; (3) hydride generation-atomic absorption spectrometry for antimony and selenium; (4) coulometric titration for carbonate carbon; and (5) combustion for total carbon and total sulfur.

Ultralow-light-level all-optical transistor in rubidium vapor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jing, Jietai, E-mail: jtjing@phy.ecnu.edu.cn; Zhou, Zhifan; Liu, Cunjin

2014-04-14

An all-optical transistor (AOT) is a device in which one light beam can efficiently manipulate another. It is the foundational component of an all-optical communication network. An AOT that can operate at ultralow light levels is especially attractive for its potential application in the quantum information field. Here, we demonstrate an AOT driven by a weak light beam with an energy density of 2.5 × 10{sup −5} photons/(λ{sup 2}/2π) (corresponding to 6  yJ/(λ{sup 2}/2π) and about 800 total photons) using the double-Λ four-wave mixing process in hot rubidium vapor. This makes it a promising candidate for ultralow-light-level optical communication and quantum information science.

A New Type of Atom Interferometry for Testing Fundamental Physics

NASA Astrophysics Data System (ADS)

Lorek, Dennis; Lämmerzahl, Claus; Wicht, Andreas

We present a new type of atom interferometer (AI) that provides a tool for ultra-high precision tests of fundamental physics. As an example we present how an AI based on highly charged hydrogen-like atoms is affected by gravitational waves (GW). A qualitative description of the quantum interferometric measurement principle is given, the modifications in the atomic Hamiltonian caused by the GW are presented, and the size of the resulting frequency shifts in hydrogen-like atoms is estimated. For a GW amplitude of h = 10-23 the frequency shift is of the order of 110μHz for an AI based on a 91-fold charged uranium ion. A frequency difference of this size can be resolved by current AIs in 1s.

Active Faraday optical frequency standard.

PubMed

Zhuang, Wei; Chen, Jingbiao

2014-11-01

We propose the mechanism of an active Faraday optical clock, and experimentally demonstrate an active Faraday optical frequency standard based on narrow bandwidth Faraday atomic filter by the method of velocity-selective optical pumping of cesium vapor. The center frequency of the active Faraday optical frequency standard is determined by the cesium 6 (2)S(1/2) F=4 to 6 (2)P(3/2) F'=4 and 5 crossover transition line. The optical heterodyne beat between two similar independent setups shows that the frequency linewidth reaches 281(23) Hz, which is 1.9×10(4) times smaller than the natural linewidth of the cesium 852-nm transition line. The maximum emitted light power reaches 75 μW. The active Faraday optical frequency standard reported here has advantages of narrow linewidth and reduced cavity pulling, which can readily be extended to other atomic transition lines of alkali and alkaline-earth metal atoms trapped in optical lattices at magic wavelengths, making it useful for new generation of optical atomic clocks.

Bearing fault diagnosis using a whale optimization algorithm-optimized orthogonal matching pursuit with a combined time-frequency atom dictionary

NASA Astrophysics Data System (ADS)

Zhang, Xin; Liu, Zhiwen; Miao, Qiang; Wang, Lei

2018-07-01

Condition monitoring and fault diagnosis of rolling element bearings are significant to guarantee the reliability and functionality of a mechanical system, production efficiency, and plant safety. However, this is almost invariably a formidable challenge because the fault features are often buried by strong background noises and other unstable interference components. To satisfactorily extract the bearing fault features, a whale optimization algorithm (WOA)-optimized orthogonal matching pursuit (OMP) with a combined time-frequency atom dictionary is proposed in this paper. Firstly, a combined time-frequency atom dictionary whose atom is a combination of Fourier dictionary atom and impact time-frequency dictionary atom is designed according to the properties of bearing fault vibration signal. Furthermore, to improve the efficiency and accuracy of signal sparse representation, the WOA is introduced into the OMP algorithm to optimize the atom parameters for best approximating the original signal with the dictionary atoms. The proposed method is validated through analyzing the bearing fault simulation signal and the real vibration signals collected from an experimental bearing and a wheelset bearing of high-speed trains. The comparisons with the respect to the state of the art in the field are illustrated in detail, which highlight the advantages of the proposed method.

Laser frequency stabilization using a commercial wavelength meter

NASA Astrophysics Data System (ADS)

Couturier, Luc; Nosske, Ingo; Hu, Fachao; Tan, Canzhu; Qiao, Chang; Jiang, Y. H.; Chen, Peng; Weidemüller, Matthias

2018-04-01

We present the characterization of a laser frequency stabilization scheme using a state-of-the-art wavelength meter based on solid Fizeau interferometers. For a frequency-doubled Ti-sapphire laser operated at 461 nm, an absolute Allan deviation below 10-9 with a standard deviation of 1 MHz over 10 h is achieved. Using this laser for cooling and trapping of strontium atoms, the wavemeter scheme provides excellent stability in single-channel operation. Multi-channel operation with a multimode fiber switch results in fluctuations of the atomic fluorescence correlated to residual frequency excursions of the laser. The wavemeter-based frequency stabilization scheme can be applied to a wide range of atoms and molecules for laser spectroscopy, cooling, and trapping.

Field optimization method of a dual-axis atomic magnetometer based on frequency-response and dynamics

NASA Astrophysics Data System (ADS)

Xing, Li; Quan, Wei; Fan, Wenfeng; Li, Rujie; Jiang, Liwei; Fang, Jiancheng

2018-05-01

The frequency-response and dynamics of a dual-axis spin-exchange-relaxation-free (SERF) atomic magnetometer are investigated by means of transfer function analysis. The frequency-response at different bias magnetic fields is tested to demonstrate the effect of the residual magnetic field. The resonance frequency of alkali atoms and magnetic linewidth can be obtained simultaneously through our theoretical model. The coefficient of determination of the fitting results is superior to 0.995 with 95% confidence bounds. Additionally, step responses are applied to analyze the dynamics of the control system and the effect of imperfections. Finally, a noise-limited magnetic field resolution of 15 fT {{\\sqrt{Hz}}-1} has been achieved for our dual-axis SERF atomic magnetometer through magnetic field optimization.

Measurement of the 4 S1 /2→6 S1 /2 transition frequency in atomic potassium via direct frequency-comb spectroscopy

NASA Astrophysics Data System (ADS)

Stalnaker, J. E.; Ayer, H. M. G.; Baron, J. H.; Nuñez, A.; Rowan, M. E.

2017-07-01

We present an experimental determination of the 4 S1 /2→6 S1 /2 transition frequency in atomic potassium 39K, using direct frequency-comb spectroscopy. The output of a stabilized optical frequency comb was used to excite a thermal atomic vapor. The repetition rate of the frequency comb was scanned and the transitions were excited using stepwise two-photon excitation. The center-of-gravity frequency for the transition was found to be νcog=822 951 698.09 (13 ) MHz and the measured hyperfine A coefficient of the 6 S1 /2 state was 21.93 (11 ) MHz. The measurements are in agreement with previous values and represent an improvement by a factor of 700 in the uncertainty of the center-of-gravity measurement.

Process for strontium-82 separation

DOEpatents

Heaton, Richard C.; Jamriska, Sr., David J.; Taylor, Wayne A.

1992-01-01

A process for selective separation of strontium-82 and strontium-85 from proton irradiated molybdenum targets comprises dissolving the molybdenum target in a hydrogen peroxide solution to form a first solution containing ions selected from a group consisting of molybdenum, niobium, technetium, selenium, vanadium, arsenic, germanium, zirconium, rubidium, zinc, beryllium, cobalt, iron, manganese, chromium, strontium, and yttrium; passing the solution through a first cationic resin whereby ions selected from a group consisting of zinc, beryllium, cobalt, iron, manganese, chromium, strontium, yttrium a portion of zirconium and a portion of rubidium are selectively absorbed by the first resin; contacting the first resin with an acid solution to strip and remove the absorbed ions from the first cationic exchange resin to form a second solution; evaporating the second solution for a time sufficient to remove substantially all of the acid and water from the solution whereby a residue remains; dissolving the residue in a dilute acid to form a third solution; passing the third solution through a second cationic resin whereby the ions are absorbed by the second resin; contacting the second resin with a dilute sulfuric acid solution whereby the absorbed ions selected from the group consisting of rubidium, zinc, beryllium, cobalt, iron, manganese, chromium and zirconium are selectively removed from the second resin; and contacting the second resin with a dilute acid solution whereby the absorbed strontium ions are selectively removed.

Process for strontium-82 separation

DOEpatents

Heaton, R.C.; Jamriska, D.J. Sr.; Taylor, W.A.

1992-12-01

A process for selective separation of strontium-82 and strontium-85 from proton irradiated molybdenum targets comprises dissolving the molybdenum target in a hydrogen peroxide solution to form a first solution containing ions selected from a group consisting of molybdenum, niobium, technetium, selenium, vanadium, arsenic, germanium, zirconium, rubidium, zinc, beryllium, cobalt, iron, manganese, chromium, strontium, and yttrium; passing the solution through a first cationic resin whereby ions selected from a group consisting of zinc, beryllium, cobalt, iron, manganese, chromium, strontium, yttrium a portion of zirconium and a portion of rubidium are selectively absorbed by the first resin; contacting the first resin with an acid solution to strip and remove the absorbed ions from the first cationic exchange resin to form a second solution; evaporating the second solution for a time sufficient to remove substantially all of the acid and water from the solution whereby a residue remains; dissolving the residue in a dilute acid to form a third solution; passing the third solution through a second cationic resin whereby the ions are absorbed by the second resin; contacting the second resin with a dilute sulfuric acid solution whereby the absorbed ions selected from the group consisting of rubidium, zinc, beryllium, cobalt, iron, manganese, chromium and zirconium are selectively removed from the second resin; and contacting the second resin with a dilute acid solution whereby the absorbed strontium ions are selectively removed. 1 fig.

Equilibrium vortex lattices of a binary rotating atomic Bose–Einstein condensate with unequal atomic masses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Biao; Wang, Lin-Xue; Chen, Guang-Ping

We perform a detailed numerical study of the equilibrium ground-state structures of a binary rotating Bose–Einstein condensate with unequal atomic masses. Our results show that the ground-state distribution and its related vortex configurations are complex events that differ markedly depending strongly on the strength of rotation frequency, as well as on the ratio of atomic masses. We also discuss the structures and radii of the clouds, the number and the size of the core region of the vortices, as a function of the rotation frequency, and of the ratio of atomic masses, and the analytical results agree well with ourmore » numerical simulations. This work may open an alternate way in the quantum control of the binary rotating quantum gases with unequal atomic masses. - Highlights: • A binary quantum gases with unequal atomic masses is considered. • Effects of the ratio of atomic masses and rotation frequency are discussed in full parameter space. • The detailed information about both the cloud and vortices are also discussed.« less

Sub-kilohertz excitation lasers for quantum information processing with Rydberg atoms

NASA Astrophysics Data System (ADS)

Legaie, Remy; Picken, Craig J.; Pritchard, Jonathan D.

2018-04-01

Quantum information processing using atomic qubits requires narrow linewidth lasers with long-term stability for high fidelity coherent manipulation of Rydberg states. In this paper, we report on the construction and characterization of three continuous-wave (CW) narrow linewidth lasers stabilized simultaneously to an ultra-high finesse Fabry-Perot cavity made of ultra-low expansion (ULE) glass, with a tunable offset-lock frequency. One laser operates at 852~nm while the two locked lasers at 1018~nm are frequency doubled to 509~nm for excitation of $^{133}$Cs atoms to Rydberg states. The optical beatnote at 509~nm is measured to be 260(5)~Hz. We present measurements of the offset between the atomic and cavity resonant frequencies using electromagnetically induced transparency (EIT) for high-resolution spectroscopy on a cold atom cloud. The long-term stability is determined from repeated spectra over a period of 20 days yielding a linear frequency drift of $\\sim1$~Hz/s.

Fast, noise-free memory for photon synchronization at room temperature.

PubMed

Finkelstein, Ran; Poem, Eilon; Michel, Ohad; Lahad, Ohr; Firstenberg, Ofer

2018-01-01

Future quantum photonic networks require coherent optical memories for synchronizing quantum sources and gates of probabilistic nature. We demonstrate a fast ladder memory (FLAME) mapping the optical field onto the superposition between electronic orbitals of rubidium vapor. Using a ladder-level system of orbital transitions with nearly degenerate frequencies simultaneously enables high bandwidth, low noise, and long memory lifetime. We store and retrieve 1.7-ns-long pulses, containing 0.5 photons on average, and observe short-time external efficiency of 25%, memory lifetime (1/ e ) of 86 ns, and below 10 -4 added noise photons. Consequently, coupling this memory to a probabilistic source would enhance the on-demand photon generation probability by a factor of 12, the highest number yet reported for a noise-free, room temperature memory. This paves the way toward the controlled production of large quantum states of light from probabilistic photon sources.

Optical atomic clocks

NASA Astrophysics Data System (ADS)

Poli, N.; Oates, C. W.; Gill, P.; Tino, G. M.

2013-12-01

In the last ten years extraordinary results in time and frequency metrology have been demonstrated. Frequency-stabilization techniques for continuous-wave lasers and femtosecond optical frequency combs have enabled a rapid development of frequency standards based on optical transitions in ultra-cold neutral atoms and trapped ions. As a result, today's best performing atomic clocks tick at an optical rate and allow scientists to perform high-resolution measurements with a precision approaching a few parts in 1018. This paper reviews the history and the state of the art in optical-clock research and addresses the implementation of optical clocks in a possible future redefinition of the SI second as well as in tests of fundamental physics.

Treatment of atomic and molecular line blanketing by opacity sampling

NASA Technical Reports Server (NTRS)

Johnson, H. R.; Krupp, B. M.

1976-01-01

A sampling technique for treating the radiative opacity of large numbers of atomic and molecular lines in cool stellar atmospheres is subjected to several tests. In this opacity sampling (OS) technique, the global opacity is sampled at only a selected set of frequencies, and at each of these frequencies the total monochromatic opacity is obtained by summing the contribution of every relevant atomic and molecular line. In accord with previous results, we find that the structure of atmospheric models is accurately fixed by the use of 1000 frequency points, and 100 frequency points are adequate for many purposes. The effects of atomic and molecular lines are separately studied. A test model computed using the OS method agrees very well with a model having identical atmospheric parameters, but computed with the giant line (opacity distribution function) method.

High power laser source for atom cooling based on reliable telecoms technology with all fibre frequency stabilisation

NASA Astrophysics Data System (ADS)

Legg, Thomas; Farries, Mark

2017-02-01

Cold atom interferometers are emerging as important tools for metrology. Designed into gravimeters they can measure extremely small changes in the local gravitational field strength and be used for underground surveying to detect buried utilities, mineshafts and sinkholes prior to civil works. To create a cold atom interferometer narrow linewidth, frequency stabilised lasers are required to cool the atoms and to setup and measure the atom interferometer. These lasers are commonly either GaAs diodes, Ti Sapphire lasers or frequency doubled InGaAsP diodes and fibre lasers. The InGaAsP DFB lasers are attractive because they are very reliable, mass-produced, frequency controlled by injection current and simply amplified to high powers with fibre amplifiers. In this paper a laser system suitable for Rb atom cooling, based on a 1560nm DFB laser and erbium doped fibre amplifier, is described. The laser output is frequency doubled with fibre coupled periodically poled LiNbO3 to a wavelength of 780nm. The output power exceeds 1 W at 780nm. The laser is stabilised at 1560nm against a fibre Bragg resonator that is passively temperature compensated. Frequency tuning over a range of 1 GHz is achieved by locking the laser to sidebands of the resonator that are generated by a phase modulator. This laser design is attractive for field deployable rugged systems because it uses all fibre coupled components with long term proven reliability.

Tuning the Sensitivity of an Optical Cavity with Slow and Fast Light

NASA Technical Reports Server (NTRS)

Smith, David D.; Myneni, Krishna; Chang, H.; Toftul, A.; Schambeau, C.; Odutola, J. A.; Diels, J. C.

2012-01-01

We have measured mode pushing by the dispersion of a rubidium vapor in a Fabry-Perot cavity and have shown that the scale factor and sensitivity of a passive cavity can be strongly enhanced by the presence of such an anomalous dispersion medium. The enhancement is the result of the atom-cavity coupling, which provides a positive feedback to the cavity response. The cavity sensitivity can also be controlled and tuned through a pole by a second, optical pumping, beam applied transverse to the cavity. Alternatively, the sensitivity can be controlled by the introduction of a second counter-propagating input beam that interferes with the first beam, coherently increasing the cavity absorptance. We show that the pole in the sensitivity occurs when the sum of the effective group index and an additional cavity delay factor that accounts for mode reshaping goes to zero, and is an example of an exceptional point, commonly associated with coupled non-Hermitian Hamiltonian systems. Additionally we show that a normal dispersion feature can decrease the cavity scale factor and can be generated through velocity selective optical pumping

Optical Frequency Standards Based on Neutral Atoms and Molecules

NASA Astrophysics Data System (ADS)

Riehle, Fritz; Helmcke, Juergen

The current status and prospects of optical frequency standards based on neutral atomic and molecular absorbers are reviewed. Special attention is given to an optical frequency standard based on cold Ca atoms which are interrogated with a pulsed excitation scheme leading to resolved line structures with a quality factor Q > 10^12. The optical frequency was measured by comparison with PTB's primary clock to be νCa = 455 986 240 494.13 kHz with a total relative uncertainty of 2.5 x10^-13. After a recent recommendation of the International Committee of Weights and Measures (CIPM), this frequency standard now represents one of the most accurate realizations of the length unit.

Observation of nonlinear optical interactions of ultralow levels of light in a tapered optical nanofiber embedded in a hot rubidium vapor.

PubMed

Spillane, S M; Pati, G S; Salit, K; Hall, M; Kumar, P; Beausoleil, R G; Shahriar, M S

2008-06-13

We report the observation of low-light level optical interactions in a tapered optical nanofiber (TNF) embedded in a hot rubidium vapor. The small optical mode area plays a significant role in the optical properties of the hot vapor Rb-TNF system, allowing nonlinear optical interactions with nW level powers even in the presence of transit-time dephasing rates much larger than the intrinsic linewidth. We demonstrate nonlinear absorption and V-type electromagnetically induced transparency with cw powers below 10 nW, comparable to the best results in any Rb-optical waveguide system. The good performance and flexibility of the Rb-TNF system makes it a very promising candidate for ultralow power resonant nonlinear optical applications.

Optical Precursor with Four-Wave Mixing and Storage Based on a Cold-Atom Ensemble

NASA Astrophysics Data System (ADS)

Ding, Dong-Sheng; Jiang, Yun Kun; Zhang, Wei; Zhou, Zhi-Yuan; Shi, Bao-Sen; Guo, Guang-Can

2015-03-01

We observed optical precursors in four-wave mixing based on a cold-atom gas. Optical precursors appear at the edges of pulses of the generated optical field, and propagate through the atomic medium without absorption. Theoretical analysis suggests that these precursors correspond to high-frequency components of the signal pulse, which means the atoms cannot respond quickly to rapid changes in the electromagnetic field. In contrast, the low-frequency signal components are absorbed by the atoms during transmission. We also showed experimentally that the backward precursor can be stored using a Raman transition of the atomic ensemble and retrieved later.

Progress toward Brazilian cesium fountain second generation

NASA Astrophysics Data System (ADS)

Bueno, Caio; Rodriguez Salas, Andrés; Torres Müller, Stella; Bagnato, Vanderlei Salvador; Varela Magalhães, Daniel

2018-03-01

The operation of a Cesium fountain primary frequency standard is strongly influenced by the characteristics of two important subsystems. The first is a stable frequency reference and the second is the frequency-transfer system. A stable standard frequency reference is key factor for experiments that require high accuracy and precision. The frequency stability of this reference has a significant impact on the procedures for evaluating certain systematic biases in frequency standards. This paper presents the second generation of the Brazilian Cesium Fountain (Br-CsF) through the opto-mechanical assembly and vacuum chamber to trap atoms. We used a squared section glass profile to build the region where the atoms are trapped and colled by magneto-optical technique. The opto-mechanical system was reduced to increase stability and robustness. This newest Atomic Fountain is essential to contribute with time and frequency development in metrology systems.

Rydberg-atom based radio-frequency electrometry using frequency modulation spectroscopy in room temperature vapor cells.

PubMed

Kumar, Santosh; Fan, Haoquan; Kübler, Harald; Jahangiri, Akbar J; Shaffer, James P

2017-04-17

Rydberg atom-based electrometry enables traceable electric field measurements with high sensitivity over a large frequency range, from gigahertz to terahertz. Such measurements are particularly useful for the calibration of radio frequency and terahertz devices, as well as other applications like near field imaging of electric fields. We utilize frequency modulated spectroscopy with active control of residual amplitude modulation to improve the signal to noise ratio of the optical readout of Rydberg atom-based radio frequency electrometry. Matched filtering of the signal is also implemented. Although we have reached similarly, high sensitivity with other read-out methods, frequency modulated spectroscopy is advantageous because it is well-suited for building a compact, portable sensor. In the current experiment, ∼3 µV cm^-1 Hz^-1/2 sensitivity is achieved and is found to be photon shot noise limited.

Berezinskii-Kosterlitz-Thouless crossover in a trapped atomic gas.

PubMed

Hadzibabic, Zoran; Krüger, Peter; Cheneau, Marc; Battelier, Baptiste; Dalibard, Jean

2006-06-29

Any state of matter is classified according to its order, and the type of order that a physical system can possess is profoundly affected by its dimensionality. Conventional long-range order, as in a ferromagnet or a crystal, is common in three-dimensional systems at low temperature. However, in two-dimensional systems with a continuous symmetry, true long-range order is destroyed by thermal fluctuations at any finite temperature. Consequently, for the case of identical bosons, a uniform two-dimensional fluid cannot undergo Bose-Einstein condensation, in contrast to the three-dimensional case. However, the two-dimensional system can form a 'quasi-condensate' and become superfluid below a finite critical temperature. The Berezinskii-Kosterlitz-Thouless (BKT) theory associates this phase transition with the emergence of a topological order, resulting from the pairing of vortices with opposite circulation. Above the critical temperature, proliferation of unbound vortices is expected. Here we report the observation of a BKT-type crossover in a trapped quantum degenerate gas of rubidium atoms. Using a matter wave heterodyning technique, we observe both the long-wavelength fluctuations of the quasi-condensate phase and the free vortices. At low temperatures, the gas is quasi-coherent on the length scale set by the system size. As the temperature is increased, the loss of long-range coherence coincides with the onset of proliferation of free vortices. Our results provide direct experimental evidence for the microscopic mechanism underlying the BKT theory, and raise new questions regarding coherence and superfluidity in mesoscopic systems.

Nonradiative transport of atomic excitation in Na vapor

NASA Astrophysics Data System (ADS)

Zajonc, Arthur G.; Phelps, A. V.

1981-05-01

Measurements are reported which show the effect of nonradiative losses at a gas-window interface on the backscattered fluorescence intensity for Na vapor at frequencies in the vicinity of the resonance lines near 589 nm. The Na 3P12,32 states are excited with a low-intensity single-mode tunable dye laser at high Na densities and the frequency integral of the backscattered fluorescence intensity in the D1 and D2 lines is measured. As the laser is tuned through resonance, the loss of atomic excitation to the window appears as a sharp decrease in the frequency-integrated fluorescence intensity. For example, at 7×1020 atoms m-3 the fluorescence intensity decreases by a factor of 4 in a frequency interval of 4 GHz. Measured absolute fluorescence intensities versus laser frequency are compared with predictions made using the theory of Hummer and Kunasz which includes both radiative and nonradiative transport processes. The agreement between theory and experiment is remarkably good when one considers that the theory contains only one unknown coefficient, i.e., the reflection coefficient for excited atoms at the windows. In our case the excited atoms are assumed to be completely destroyed at the window.

Adiabatic passage of radio-frequency-assisted Förster resonances in Rydberg atoms for two-qubit gates and the generation of Bell states

NASA Astrophysics Data System (ADS)

Beterov, I. I.; Hamzina, G. N.; Yakshina, E. A.; Tretyakov, D. B.; Entin, V. M.; Ryabtsev, I. I.

2018-03-01

High-fidelity entangled Bell states are of great interest in quantum physics. Entanglement of ultracold neutral atoms in two spatially separated optical dipole traps is promising for implementation of quantum computing and quantum simulation and for investigation of Bell states of material objects. We propose a method to entangle two atoms via long-range Rydberg-Rydberg interaction. Alternative to previous approaches, based on Rydberg blockade, we consider radio-frequency-assisted Stark-tuned Förster resonances in Rb Rydberg atoms. To reduce the sensitivity of the fidelity of Bell states to the fluctuations of interatomic distance, we propose to use the double adiabatic passage across the radio-frequency-assisted Stark-tuned Förster resonances, which results in a deterministic phase shift of the collective two-atom state.

Modulation Transfer Through Coherence and Its Application to Atomic Frequency Offset Locking

NASA Astrophysics Data System (ADS)

Jagatap, B. N.; Ray, Ayan; Kale, Y. B.; Singh, Niharika; Lawande, Q. V.

We discuss the process of modulation transfer in a coherently prepared three-level atomic medium and its prospective application to atomic frequency offset locking (AFOL). The issue of modulation transfer through coherence is treated in the framework of temporal evolution of dressed atomic system with externally superimposed deterministic flow. This dynamical description of the atom-field system offers distinctive advantage of using a single modulation source to dither passively the coherent phenomenon as probed by an independent laser system under pump-probe configuration. Modulation transfer is demonstrated experimentally using frequency modulation spectroscopy on a subnatural linewidth electromagnetically induced transparency (EIT) and a sub-Doppler linewidth Autler-Townes (AT) resonance in Doppler broadened alkali vapor medium, and AFOL is realized by stabilizing the probe laser on the first/third derivative signals. The stability of AFOL is discussed in terms of the frequency noise power spectral density and Allan variance. Analysis of AFOL schemes is carried out at the backdrop of closed loop active frequency control in a conventional master-slave scheme to point out the contrasting behavior of AFOL schemes based on EIT and AT resonances. This work adds up to the discussion on the subtle link between dressed state spectroscopy and AFOL, which is relevant for developing a master-slave type laser system in the domain of coherent photon-atom interaction.

Fifty years of atomic time-keeping at VNIIFTRI

NASA Astrophysics Data System (ADS)

Domnin, Yu; Gaigerov, B.; Koshelyaevsky, N.; Poushkin, S.; Rusin, F.; Tatarenkov, V.; Yolkin, G.

2005-06-01

Time metrology in Russia in the second half of the twentieth century has been marked, as in other advanced countries, by the rapid development of time and frequency quantum standards and the beginning of atomic time-keeping. This brief review presents the main developments and studies in time and frequency measurement, and the improvement of accuracy and atomic time-keeping at the VNIIFTRI—the National Metrology Institute keeping primary time and frequency standards and ensuring unification of measurement. The milestones along the way have been the ammonia and hydrogen masers, primary caesium beam and fountain standards and laser frequency standards. For many years, VNIIFTRI was the only world laboratory that applied hydrogen-maser clock ensembles for time-keeping. VNIIFTRI's work on international laser standard frequency comparisons and absolute frequency measurements contributed greatly to the adoption by the CIPM of a highly accurate value for the He-Ne/CH4 laser frequency. VNIIFTRI and the VNIIM were the first to establish a united time, frequency and length standard.

Carrier Envelope Phase Effect of a Long Duration Pulse in the Low Frequency Region

NASA Astrophysics Data System (ADS)

Zhao, Xi; Yang, Yu-Jun; Liu, Xue-Shen; Wang, Bing-Bing

2014-04-01

Using the characteristic of small energy difference between two high Rydberg states, we theoretically investigate the carrier envelope phase (CEP) effect in a bound-bound transition of an atom in a low-frequency long laser pulse with tens of optical cycles. Particularly, we first prepare a Rydberg state of a hydrogen-like atom by a laser field with the resonant frequency between this state and the ground state. Then by using a low-frequency long laser pulse interacting with this Rydberg atom, we calculate the population of another Rydberg state nearby this Rydberg state at the end of the laser pulse and find that the population changes dramatically with the CEP of the low-frequency pulse. This CEP effect is attributed to the interference between the positive-frequency and negative-frequency components in one-photon transition. These results may provide a method to measure the CEP value of a long laser pulse with low frequency.

Definitions of Frequency and Timing Terms, Satellite Navigation and Timing Systems, and the Behavior and Analyses of Precision Crystal and Atomic Frequency Standards and their Characteristics

DTIC Science & Technology

2009-05-01

time transfer techniques has largely been due to the improvement in frequency standards. In this document, an effort was made to provide substantial...of RCC Document 214-94, contains definitions of frequency and timing terms, time transfer techniques and analysis, and behavior of crystal and atomic...Characteristics, May 2009 viii TTG Telecommunications and Timing Group TWSTFT Two-Way Satellite Time and Frequency Transfer U.S. United States USNO

Note: Directly measuring the direct digital synthesizer frequency chirp-rate for an atom interferometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tao, Juan-Juan; Zhou, Min-Kang, E-mail: zkhu@hust.edu.cn, E-mail: zmk@hust.edu.cn; Zhang, Qiao-Zhen

2015-09-15

During gravity measurements with Raman type atom interferometry, the frequency of the laser used to drive Raman transition is scanned by chirping the frequency of a direct digital synthesizer (DDS), and the local gravity is determined by precisely measuring the chip rate α of DDS. We present an effective method that can directly evaluate the frequency chirp rate stability of our DDS. By mixing a pair of synchronous linear sweeping signals, the chirp rate fluctuation is precisely measured with a frequency counter. The measurement result shows that the relative α instability can reach 5.7 × 10{sup −11} in 1 s,more » which is neglectable in a 10{sup −9} g level atom interferometry gravimeter.« less

Wideband digital frequency detector with subtraction-based phase comparator for frequency modulation atomic force microscopy.

PubMed

Mitani, Yuji; Kubo, Mamoru; Muramoto, Ken-ichiro; Fukuma, Takeshi

2009-08-01

We have developed a wideband digital frequency detector for high-speed frequency modulation atomic force microscopy (FM-AFM). We used a subtraction-based phase comparator (PC) in a phase-locked loop circuit instead of a commonly used multiplication-based PC, which has enhanced the detection bandwidth to 100 kHz. The quantitative analysis of the noise performance revealed that the internal noise from the developed detector is small enough to provide the theoretically limited noise performance in FM-AFM experiments in liquid. FM-AFM imaging of mica in liquid was performed with the developed detector, showing its stability and applicability to true atomic-resolution imaging in liquid.

Navigation with Atom Interferometers

DTIC Science & Technology

2017-03-20

cos(1[ 2 1)( ttP g g e    (1) where  2  is the zero detuning Rabi frequency,  is the atomic dipole moment, 22  g is the...generalized Rabi frequency and oL   is the detuning of the laser from the atomic transition. Distribution A: Approved for public release; distribution

‘And then there were three’: highly efficient uptake of potassium by foliar trichomes of epiphytic bromeliads

PubMed Central

Winkler, Uwe; Zotz, Gerhard

2010-01-01

Background and Aims Vascular epiphytes have to acquire nutrients from atmospheric wash out, stem-flow, canopy soils and trapped litter. Physiological studies on the adaptations to nutrient acquisition and plant utilization of nutrients have focused on phosphorus and nitrogen; potassium, as a third highly abundant nutrient element, has received minor attention. In the present study, potassium uptake kinetics by leaves, within-plant distribution and nutrient accumulation were analysed to gain an improved understanding of physiological adaptations to non-terrestrial nutrient supply of plants. Methods Radioactively labelled 86RbCl was used as an analogue to study uptake kinetics of potassium absorbed from tanks of epiphytes, its plant distribution and the correlation between uptake efficiency and abundance of trichomes, functioning as uptake organs of leaves. Potassium in leaves was additionally analysed by atomic absorption spectroscopy to assess plant responses to potassium deficiency. Key Results Labelled rubidium was taken up from tanks over a wide range of concentrations, 0·01–90 mm, which was achieved by two uptake systems. In four tank epiphytes, the high-affinity transporters had average Km values of 41·2 µm, and the low-affinity transporters average Km values of 44·8 mm. Further analysis in Vriesea splenriet showed that high-affinity uptake of rubidium was an ATP-dependent process, while low-affinity uptake was mediated by a K+-channel. The kinetic properties of both types of transporters are comparable with those of potassium transporters in roots of terrestrial plants. Specific differences in uptake velocities of epiphytes are correlated with the abundance of trichomes on their leaf surfaces. The main sinks for potassium were fully grown leaves. These leaves thus function as internal potassium sources, which allow growth to be maintained during periods of low external potassium availability. Conclusions Vascular epiphytes possess effective mechanisms to take up potassium from both highly diluted and highly concentrated solutions, enabling the plant to incorporate this nutrient element quickly and almost quantitatively from tank solutions. A surplus not needed for current metabolism is stored, i.e. plants show luxury consumption. PMID:20542886

Optical Measurements of Strong Radio-Frequency Fields Using Rydberg Atoms

NASA Astrophysics Data System (ADS)

Miller, Stephanie Anne

There has recently been an initiative toward establishing atomic measurement standards for field quantities, including radio-frequency, millimeter-wave, and micro-wave electric fields. Current measurement standards are obtained using dipole antennas, which are fundamentally limited in frequency bandwidth (set by the physical size of the antenna) and accuracy (due to the metal perturbing the field during the measurement). Establishing an atomic standard rectifies these problems. My thesis work contributes to an ongoing effort towards establishing the viability of using Rydberg electromagnetically induced transparency (EIT) to perform atom-based measurements of radio-frequency (RF) fields over a wide range of frequencies and field strengths, focusing on strong-field measurements. Rydberg atoms are atoms with an electron excited to a high principal quantum number, resulting in a high sensitivity to an applied field. A model based on Floquet theory is implemented to accurately describe the observed atomic energy level shifts from which information about the field is extracted. Additionally, the effects due to the different electric field domains within the measurement volume are accurately modeled. Absolute atomic measurements of fields up to 296 V/m within a +/-0.35% relative uncertainty are demonstrated. This is the strongest field measured at the time of data publication. Moreover, the uncertainty is over an order of magnitude better than that of current standards. A vacuum chamber setup that I implemented during my graduate studies is presented and its unique components are detailed. In this chamber, cold-atom samples are generated and Rydberg atoms are optically excited within the ground-state sample. The Rydberg ion detection and imaging procedure are discussed, particularly the high magnification that the system provides. By analyzing the position of the ions, the spatial correlation g(2) (r) of Rydberg-atom distributions can be extracted. Aside from ion detection, EIT is implemented in the cold-atom samples. By measuring the timing of the probe photons exiting the EIT medium, the temporal correlation function g(2)(tau) can be extracted, yielding information about the timing between two different arbitrary photons. An experimental goal using this setup is to look at g(2)(tau) in conjunction with g(2)(r) for Rydberg atoms. Progress and preliminary measurements of ion detection and EIT spectra are presented including observed qualitative behaviors.

Radio-frequency Electrometry Using Rydberg Atoms in Vapor Cells: Towards the Shot Noise Limit

NASA Astrophysics Data System (ADS)

Kumar, Santosh; Fan, Haoquan; Jahangiri, Akbar; Kuebler, Harald; Shaffer, James P.; 5. Physikalisches Institut, Universitat Stuttgart, Germany Collaboration

2016-05-01

Rydberg atoms are a promising candidate for radio frequency (RF) electric field sensing. Our method uses electromagnetically induced transparency with Rydberg atoms in vapor cells to read out the effect that the RF electric field has on the Rydberg atoms. The method has the potential for high sensitivity (pV cm-1 Hz- 1 / 2) and can be self-calibrated. Some of the main factors limiting the sensitivity of RF electric field sensing from reaching the shot noise limit are the residual Doppler effect and the sensitivity of the optical read-out using the probe laser. We present progress on overcoming the residual Doppler effect by using a new multi-photon scheme and reaching the shot noise detection limit using frequency modulated spectroscopy. Our experiments also show promise for studying quantum optical effects such as superradiance in vapor cells using Rydberg atoms. This work is supported by DARPA, ARO, and NRO.

The effect of electromagnetically induced transparency in a potassium nanocell

NASA Astrophysics Data System (ADS)

Sargsyan, A.; Amiryan, A.; Leroy, C.; Vartanyan, T. A.; Sarkisyan, D.

2017-07-01

The effect of electromagnetically induced transparency (EIT) has been experimentally implemented for the first time for the (4 S 1/2-4 P 1/2-4 S 1/2) Λ-system of potassium atom levels in a nanocell with a 770-nm-thick column of atomic vapor. It is shown that, at such a small thickness of the vapor column, the EIT resonance can be observed only when the coupling-laser frequency is in exact resonance with the frequency of the corresponding atomic transition. The EIT resonance disappears even if the coupling-laser frequency differs slightly (by 50 MHz) from that of the corresponding atomic transition, which is due to the high thermal velocity of K atoms. The EIT resonance and related velocity selective optical pumping resonances caused by optical pumping (formed by the coupling) can be simultaneously recorded because of the small ( 462 MHz) hyperfine splitting of the lower 4 S 1/2 level.

40 CFR 721.4740 - Alkali metal nitrites.

Code of Federal Regulations, 2010 CFR

2010-07-01

... periodic classification of chemical elements) lithium, sodium, potassium, rubidium, cesium, and francium... defined in 40 CFR 721.3) containing amines. (b) [Reserved] [58 FR 27944, May 12, 1993, as amended at 58 FR...

40 CFR 721.4740 - Alkali metal nitrites.

Code of Federal Regulations, 2011 CFR

2011-07-01

... periodic classification of chemical elements) lithium, sodium, potassium, rubidium, cesium, and francium... defined in 40 CFR 721.3) containing amines. (b) [Reserved] [58 FR 27944, May 12, 1993, as amended at 58 FR...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varma, S.D.; Mooney, J.M.

Studies have been conducted to examine the implications of photochemical generation of O2- and its derivatization to H/sub 2/O/sub 2/ and OH in the physiology of the lens in vitro. Physiological status was determined by measuring the uptake of rubidium by the intact tissue when cultured in riboflavin-containing medium, in dark and light, and in the presence and absence of various scavengers. In the presence of light, the uptake of rubidium in the lens was greatly diminished; this suggests photodamage to the tissue. MnSOD and ferricyanide protected against this photochemical damage. The damaging process was thus initiated by the generationmore » of O2-. The tissue damage was also attenuated by catalase, ferrocyanide, and mannitol. These results, therefore, suggest the participation of hydrogen peroxide and the subsequent Haber-Weiss reaction in the photodamaging process.« less

Neuropsychiatric manifestations of alkali metal deficiency and excess

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yung, C.Y.

1984-01-01

The alkali metals from the Group IA of the periodic table (lithium, sodium, potassium, rubidium, cesium and francium) are reviewed. The neuropsychiatric aspects of alkali metal deficiencies and excesses (intoxications) are described. Emphasis was placed on lithium due to its clinical uses. The signs and symptoms of these conditions are characterized by features of an organic brain syndrome with delirium and encephalopathy prevailing. There are no clinically distinctive features that could be reliably used for diagnoses. Sodium and potassium are two essential alkali metals in man. Lithium is used as therapeutic agent in bipolar affective disorders. Rubidium has been investigatedmore » for its antidepressant effect in a group of psychiatric disorders. Cesium is under laboratory investigation for its role in carcinogenesis and in depressive illness. Very little is known of francium due to its great instability for experimental study.« less

Elemental content of tissues and excreta of lambs, goats, and kids fed white sweet clover growing on fly ash

DOE Office of Scientific and Technical Information (OSTI.GOV)

Furr, A.K.; Parkinson, T.F.; Heffron, C.L.

White sweet clover found voluntarily growing on a deep bed of soft coal fly ash was found to contain high concentrations of a number of elements including selenium, bromine, and molybdenum, rubidium, strontium, and others. The clover was harvested and fed as 23.5% of a dry pelleted ration to lambs and pregnant goats for up to 173 days. High concentrations of selenium were found in 11 tissues, blood, goats' milk, and excreta of lambs, goats, and newborn kids. Molybdenum in liver, strontium in bone, and bromine and rubidium in animal tissues were also elevated over those in the corresponding tissuesmore » of animals fed an identical ration containing control clover grown on soil. No gross or histologic lesions were present in any of the animals.« less

Trace elements in patients on continuous renal replacement therapy.

PubMed

Broman, M; Bryland, A; Carlsson, O

2017-07-01

Intensive care patients with acute kidney injury (AKI), treated with continuous renal replacement therapy (CRRT) are at great risk for disturbances in plasma levels of trace elements due to the underlying illness, AKI, and dialysis. This study was performed to increase our knowledge regarding eight different trace elements during CRRT. Thirty one stable patients with AKI, treated with CRRT, were included in the study. Blood, plasma and effluent samples were taken at the start of the study and 36 ± 12 h later. A group of 48 healthy volunteers were included as controls and exposed to one fasting blood sample. Samples were analysed for trace elements (Cr, Cu, Mn, Co, Zn, Rb, Mo, Se) and standard blood chemistry. Blood and plasma levels of selenium and rubidium were significantly reduced while the levels of chromium, cobalt, and molybdenum were significantly increased in the study group vs. healthy volunteers. There was an uptake of chromium, manganese, and zinc. Molybdenum mass balance was around zero. For selenium, copper, and rubidium there were a marked loss. The low levels of selenium and rubidium in blood and plasma from CRRT patients, together with the loss via CRRT effluent, raises the possibility of the need for selenium supplementation in this group of patients, despite the unchanged levels during the short study period. Further investigations on the effect of additional administration of trace elements to CRRT patients would be of interest. © 2017 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

The calculation of molecular Eigen-frequencies

NASA Technical Reports Server (NTRS)

Lindemann, F. A.

1984-01-01

A method of determining molecular eigen-frequencies based on the function of Einstein expressing the variation of the atomic heat of various elements is proposed. It is shown that the same equation can be utilized to calculate both atomic heat and optically identifiably eigen-frequencies - at least to an order of magnitude - suggesting that in both cases the same oscillating structure is responsible.

Atom Interferometry: A Matter Wave Clock and a Measurement of α

NASA Astrophysics Data System (ADS)

Estey, Brian; Lan, Shau-Yu; Kuan, Pei-Chen; Hohensee, Michael; Haslinger, Philipp; Kehayias, Pauli; English, Damon; Müller, Holger

2012-06-01

Developments in large-momentum transfer beamsplitters (eg. Bragg diffraction) and conjugate Ramsey-Bord'e interferometers have enabled atom interferometers with unparalleled size and sensitivity. The atomic wave packet separation is large enough that the Coriolis force due to the earth's rotation reduces interferometer contrast. We compensate for this effect using a tip-tilt mirror, improving our contrast by up to a factor of 3.5, allowing pulse separations of up to 250 ms with 10k beamsplitters. This interferometer can be used to make a precise measurement of the recoil frequency (h/m) and thus the fine structure constant. The interferometer also gives us indirect access to the Compton frequency (νC≡mc^2/h) oscillations of the matter wave, since h/m is simply c^2/νC. Using an optical frequency comb we reference the interferometer's laser frequency to a multiple of a cesium atom's recoil frequency. This self-referenced interferometer thus locks a local oscillator to a specified fraction of the cesium Compton frequency, with a fractional stability of 2 pbb over several hours. This has potential application in redefining the kilogram in terms of the second. We also present a preliminary measurement of the fine structure constant.

Portable atomic frequency standard based on coherent population trapping

NASA Astrophysics Data System (ADS)

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.

Enhanced optical nonlinearity and fiber-optical frequency comb controlled by a single atom in a whispering-gallery-mode microtoroid resonator

NASA Astrophysics Data System (ADS)

Li, Jiahua; Zhang, Suzhen; Yu, Rong; Zhang, Duo; Wu, Ying

2014-11-01

Based on a single atom coupled to a fiber-coupled, chip-based microresonator [B. Dayan et al., Science 319, 1062 (2008), 10.1126/science.1152261], we put forward a scheme to generate optical frequency combs at driving laser powers as low as a few nanowatts. Using state-of-the-art experimental parameters, we investigate in detail the influences of different atomic positions and taper-resonator coupling regimes on optical-frequency-comb generation. In addition to numerical simulations demonstrating this effect, a physical explanation of the underlying mechanism is presented. We find that the combination of the atom and the resonator can induce a large third-order nonlinearity which is significantly stronger than Kerr nonlinearity in Kerr frequency combs. Such enhanced nonlinearity can be used to generate optical frequency combs if driven with two continuous-wave control and probe lasers and significantly reduce the threshold of nonlinear optical processes. The comb spacing can be well tuned by changing the frequency beating between the driving control and probe lasers. The proposed method is versatile and can be adopted to different types of resonators, such as microdisks, microspheres, microtoroids or microrings.

Frequency comb transferred by surface plasmon resonance

PubMed Central

Geng, Xiao Tao; Chun, Byung Jae; Seo, Ji Hoon; Seo, Kwanyong; Yoon, Hana; Kim, Dong-Eon; Kim, Young-Jin; Kim, Seungchul

2016-01-01

Frequency combs, millions of narrow-linewidth optical modes referenced to an atomic clock, have shown remarkable potential in time/frequency metrology, atomic/molecular spectroscopy and precision LIDARs. Applications have extended to coherent nonlinear Raman spectroscopy of molecules and quantum metrology for entangled atomic qubits. Frequency combs will create novel possibilities in nano-photonics and plasmonics; however, its interrelation with surface plasmons is unexplored despite the important role that plasmonics plays in nonlinear spectroscopy and quantum optics through the manipulation of light on a subwavelength scale. Here, we demonstrate that a frequency comb can be transformed to a plasmonic comb in plasmonic nanostructures and reverted to the original frequency comb without noticeable degradation of <6.51 × 10−19 in absolute position, 2.92 × 10−19 in stability and 1 Hz in linewidth. The results indicate that the superior performance of a well-defined frequency comb can be applied to nanoplasmonic spectroscopy, quantum metrology and subwavelength photonic circuits. PMID:26898307

Frequency redistribution function for the polarized two-term atom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Casini, R.; Landi Degl'Innocenti, M.; Manso Sainz, R.

2014-08-20

We present a generalized frequency redistribution function for the polarized two-term atom in an arbitrary magnetic field. This result is derived within a new formulation of the quantum problem of coherent scattering of polarized radiation by atoms in the collisionless regime. The general theory, which is based on a diagrammatic treatment of the atom-photon interaction, is still a work in progress. However, the results anticipated here are relevant enough for the study of the magnetism of the solar chromosphere and of interest for astrophysics in general.

Nanoscale Subsurface Imaging via Resonant Difference-Frequency Atomic Force Ultrasonic Microscopy

NASA Technical Reports Server (NTRS)

Cantrell, Sean A.; Cantrell, John H.; Lilehei, Peter T.

2007-01-01

A novel scanning probe microscope methodology has been developed that employs an ultrasonic wave launched from the bottom of a sample while the cantilever of an atomic force microscope, driven at a frequency differing from the ultrasonic frequency by the fundamental resonance frequency of the cantilever, engages the sample top surface. The nonlinear mixing of the oscillating cantilever and the ultrasonic wave in the region defined by the cantilever tip-sample surface interaction force generates difference-frequency oscillations at the cantilever fundamental resonance. The resonance-enhanced difference-frequency signals are used to create images of embedded nanoscale features.

Dynamic regime of coherent population trapping and optimization of frequency modulation parameters in atomic clocks.

PubMed

Yudin, V I; Taichenachev, A V; Basalaev, M Yu; Kovalenko, D V

2017-02-06

We theoretically investigate the dynamic regime of coherent population trapping (CPT) in the presence of frequency modulation (FM). We have formulated the criteria for quasi-stationary (adiabatic) and dynamic (non-adiabatic) responses of atomic system driven by this FM. Using the density matrix formalism for Λ system, the error signal is exactly calculated and optimized. It is shown that the optimal FM parameters correspond to the dynamic regime of atomic-field interaction, which significantly differs from conventional description of CPT resonances in the frame of quasi-stationary approach (under small modulation frequency). Obtained theoretical results are in good qualitative agreement with different experiments. Also we have found CPT-analogue of Pound-Driver-Hall regime of frequency stabilization.

A Study of the Hydration of the Alkali Metal Ions in Aqueous Solution

PubMed Central

2011-01-01

The hydration of the alkali metal ions in aqueous solution has been studied by large angle X-ray scattering (LAXS) and double difference infrared spectroscopy (DDIR). The structures of the dimethyl sulfoxide solvated alkali metal ions in solution have been determined to support the studies in aqueous solution. The results of the LAXS and DDIR measurements show that the sodium, potassium, rubidium and cesium ions all are weakly hydrated with only a single shell of water molecules. The smaller lithium ion is more strongly hydrated, most probably with a second hydration shell present. The influence of the rubidium and cesium ions on the water structure was found to be very weak, and it was not possible to quantify this effect in a reliable way due to insufficient separation of the O–D stretching bands of partially deuterated water bound to these metal ions and the O–D stretching bands of the bulk water. Aqueous solutions of sodium, potassium and cesium iodide and cesium and lithium hydroxide have been studied by LAXS and M–O bond distances have been determined fairly accurately except for lithium. However, the number of water molecules binding to the alkali metal ions is very difficult to determine from the LAXS measurements as the number of distances and the temperature factor are strongly correlated. A thorough analysis of M–O bond distances in solid alkali metal compounds with ligands binding through oxygen has been made from available structure databases. There is relatively strong correlation between M–O bond distances and coordination numbers also for the alkali metal ions even though the M–O interactions are weak and the number of complexes of potassium, rubidium and cesium with well-defined coordination geometry is very small. The mean M–O bond distance in the hydrated sodium, potassium, rubidium and cesium ions in aqueous solution have been determined to be 2.43(2), 2.81(1), 2.98(1) and 3.07(1) Å, which corresponds to six-, seven-, eight- and eight-coordination. These coordination numbers are supported by the linear relationship of the hydration enthalpies and the M–O bond distances. This correlation indicates that the hydrated lithium ion is four-coordinate in aqueous solution. New ionic radii are proposed for four- and six-coordinate lithium(I), 0.60 and 0.79 Å, respectively, as well as for five- and six-coordinate sodium(I), 1.02 and 1.07 Å, respectively. The ionic radii for six- and seven-coordinate K+, 1.38 and 1.46 Å, respectively, and eight-coordinate Rb+ and Cs+, 1.64 and 1.73 Å, respectively, are confirmed from previous studies. The M–O bond distances in dimethyl sulfoxide solvated sodium, potassium, rubidium and cesium ions in solution are very similar to those observed in aqueous solution. PMID:22168370

Low-frequency, self-sustained oscillations in inductively coupled plasmas used for optical pumping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coffer, J.; Encalada, N.; Huang, M.

We have investigated very low frequency, on the order of one hertz, self-pulsing in alkali-metal inductively-coupled plasmas (i.e., rf-discharge lamps). This self-pulsing has the potential to significantly vary signal-to-noise ratios and (via the ac-Stark shift) resonant frequencies in optically pumped atomic clocks and magnetometers (e.g., the atomic clocks now flying on GPS and Galileo global navigation system satellites). The phenomenon arises from a nonlinear interaction between the atomic physics of radiation trapping and the plasma's electrical nature. To explain the effect, we have developed an evaporation/condensation theory (EC theory) of the self-pulsing phenomenon.

Robust sub-millihertz-level offset locking for transferring optical frequency accuracy and for atomic two-photon spectroscopy.

PubMed

Cheng, Wang-Yau; Chen, Ting-Ju; Lin, Chia-Wei; Chen, Bo-Wei; Yang, Ya-Po; Hsu, Hung Yi

2017-02-06

Robust sub-millihertz-level offset locking was achieved with a simple scheme, by which we were able to transfer the laser frequency stability and accuracy from either cesium-stabilized diode laser or comb laser to the other diode lasers who had serious frequency jitter previously. The offset lock developed in this paper played an important role in atomic two-photon spectroscopy with which record resolution and new determination on the hyperfine constants of cesium atom were achieved. A quantum-interference experiment was performed to show the improvement of light coherence as an extended design was implemented.

A universal quantum frequency converter via four-wave-mixing processes

NASA Astrophysics Data System (ADS)

Cheng, Mingfei; Fang, Jinghuai

2016-06-01

We present a convenient and flexible way to realize a universal quantum frequency converter by using nondegenerate four-wave-mixing processes in the ladder-type three-level atomic system. It is shown that quantum state exchange between two fields with large frequency difference can be readily achieved, where one corresponds to the atomic resonant transition in the visible spectral region for quantum memory and the other to the telecommunication range wavelength (1550 nm) for long-distance transmission over optical fiber. This method would bring great facility in realistic quantum information processing protocols with atomic ensembles as quantum memory and low-loss optical fiber as transmission channel.

Length-extension resonator as a force sensor for high-resolution frequency-modulation atomic force microscopy in air.

PubMed

Beyer, Hannes; Wagner, Tino; Stemmer, Andreas

2016-01-01

Frequency-modulation atomic force microscopy has turned into a well-established method to obtain atomic resolution on flat surfaces, but is often limited to ultra-high vacuum conditions and cryogenic temperatures. Measurements under ambient conditions are influenced by variations of the dew point and thin water layers present on practically every surface, complicating stable imaging with high resolution. We demonstrate high-resolution imaging in air using a length-extension resonator operating at small amplitudes. An additional slow feedback compensates for changes in the free resonance frequency, allowing stable imaging over a long period of time with changing environmental conditions.

Study of magnetic resonance with parametric modulation in a potassium vapor cell

NASA Astrophysics Data System (ADS)

Zhang, Rui; Wang, Zhiguo; Peng, Xiang; Li, Wenhao; Li, Songjian; Guo, Hong; Cream Team

2017-04-01

A typical magnetic-resonance scheme employs a static bias magnetic field and an orthogonal driving magnetic field oscillating at the Larmor frequency, at which the atomic polarization precesses around the static magnetic field. We demonstrate in a potassium vapor cell the variations of the resonance condition and the spin precession dynamics resulting from the parametric modulation of the bias field, which are in well agreement with theoretical predictions from the Bloch equation. We show that, the driving magnetic field with the frequency detuned by different harmonics of the parametric modulation frequency can lead to resonance as well. Also, a series of frequency sidebands centered at the driving frequency and spaced by the parametric modulation frequency can be observed in the precession of the atomic polarization. These effects could be used in different atomic magnetometry applications. This work is supported by the National Science Fund for Distinguished Young Scholars of China (Grant No. 61225003) and the National Natural Science Foundation of China (Grant Nos. 61531003 and 61571018).

Theoretical investigation of output features of a diode-pumped rubidium vapor laser

NASA Astrophysics Data System (ADS)

Wang, You; Cai, He; Zhang, Wei; Xue, Liangping; Wang, Hongyuan; Han, Juhong

2014-02-01

In the recent years, diode-pumped alkali lasers (DPALs) have been paid many attentions because of their excellent performances. In fact, the characteristics of a DPAL strongly depend on the physical features of buffer gases. In this report, we selected a diode-pumped rubidium vapor laser (DPRVL), which is an important type among three common DPALs, to investigate how the characteristics of a DPRVL are affected by different conditions. The results signify that the population ratio of two excitation energy-levels are close to that corresponding to thermal equilibrium as the pressure of buffer gases and the temperature of a vapor cell become higher. It has been found that quenching of the upper levels cannot be simply ignored especially for the case of weak pump. The conclusions are thought to be helpful for the configuration design of an end-pumped DPAL.

Low cost photonic comb for sub-m/s wavelength calibration

NASA Astrophysics Data System (ADS)

Betters, Christopher H.; Hermouet, Maxime; Blanc, Thomas; Colless, James I.; Bland-Hawthorn, Joss; Kos, Janez; Leon-Saval, Sergio

2016-07-01

A fundamental limitation of precision radial velocity measurements is the accuracy and stability of the calibration source. Here we present a low-cost alternative to more complex laser metrology based systems that utilises a single-mode fibre Fabry-Perot etalon. There are three key elements on this photonic comb: i) an optical fibre etalon with thermo-electric coolers; ii) a Rubidium Saturation Absorption Spectroscopy (SAS) setup; and iii) an optical fibre switch system for simultaneous laser locking of the etalon. We simultaneously measure the Rubidium D2 transitions around 780.2 nm and the closest etalon line. A PID loop controls the etalon temperate to maintain the position of its peak with an RMS error of <10cm/s for 10 minute integration intervals in continous operation. The optical fibre switch system allows for a time multiplexed coupling of the etalon to a spectrograph and SAS system.

Demonstration of a diode-laser-based high spectral resolution lidar (HSRL) for quantitative profiling of clouds and aerosols.

PubMed

Hayman, Matthew; Spuler, Scott

2017-11-27

We present a demonstration of a diode-laser-based high spectral resolution lidar. It is capable of performing calibrated retrievals of aerosol and cloud optical properties at a 150 m range resolution with less than 1 minute integration time over an approximate range of 12 km during day and night. This instrument operates at 780 nm, a wavelength that is well established for reliable semiconductor lasers and detectors, and was chosen because it corresponds to the D2 rubidium absorption line. A heated vapor reference cell of isotopic rubidium 87 is used as an effective and reliable aerosol signal blocking filter in the instrument. In principle, the diode-laser-based high spectral resolution lidar can be made cost competitive with elastic backscatter lidar systems, yet delivers a significant improvement in data quality through direct retrieval of quantitative optical properties of clouds and aerosols.

Recovery of niobium from irradiated targets

DOEpatents

Phillips, Dennis R.; Jamriska, Sr., David J.; Hamilton, Virginia T.

1994-01-01

A process for selective separation of niobium from proton irradiated molybdenum targets is provided and includes dissolving the molybdenum target in a hydrogen peroxide solution to form a first ion-containing solution, contacting the first ion-containing solution with a cationic resin whereby ions selected form the group consisting of molybdenum, biobium, technetium, selenium, vanadium, arsenic, germanium, zirconium and rubidium remain in a second ion-containing solution while ions selected from the group consisting of rubidium, zinc, beryllium, cobalt, iron, manganese, chromium, strontium, yttrium and zirconium are selectively adsorbed by the cationic resin; adjusting the pH of the second ion-containing solution to within a range of from about 5.0 to about 6.0; contacting the pH adjusting second ion-containing solution with a dextran-based material for a time to selectively separate niobium from the solution and recovering the niobium from the dextran-based material.

Kinetic parameters of rubidium transport pathways are normal in cystic fibrosis red cells.

PubMed

Joiner, C H

1988-10-01

The abnormalities in ion transport in cystic fibrosis (CF) respiratory and sweat duct epithelia have prompted studies of ion permeability in CF red blood cells (RBC) although previous reports have been contradictory. In this study, the kinetic characteristics of the three major cation transport systems in RBC were evaluated by measuring rubidium (Rb) uptake at various external Rb concentrations. The maximal velocity and affinity for external Rb (K1/2) of the NaK pump were normal in CF RBC, as were the maximal velocity and Km for Rb of the NaK cotransport system. Residual (ouabain and bumetanide insensitive) Rb uptake, and steady state RBC Na and K contents were also normal. These data indicate the NaK pump and cotransport system do not exhibit primary or secondary perturbations in CF RBC, and suggest that the noncarrier-mediated membrane permeability to cations is also normal in these cells.

Ab-initio investigation of Rb substitution in KTP single crystal

NASA Astrophysics Data System (ADS)

Ghoohestani, Marzieh; Arab, Ali; Hashemifar, S. Javad; Sadeghi, Hossein

2018-01-01

The effects of rubidium doping on the structural, electronic, and optical properties of KTiOPO4 (KTP) are investigated in the framework of density functional theory. The equilibrium structural parameters of KTP and RbTiOPO4 (RTP) are calculated within the local density and Perdew-Burke-Ernzerhof (PBE), Wu-Cohen, and PBEsol formulation of generalized gradient approximations. We discuss that PBEsol predicts better equilibrium parameters for the KTP alloy. In addition, the variation of lattice constants and Ti-O-Ti bond angles are evaluated as a function of rubidium concentration. The modern modified Becke-Johnson functional is applied for more accurate band gap determination in the pure and alloyed KTP/RTP compounds. The phenomenological pseudoinversion parameter is calculated for a qualitative understanding of the effect of impurity on a non-linear optical response of KTP. We also analyze the behavior of the dielectric function, dispersive refractive indices, and birefringence of KTP/RTP alloys.

Study of the phase transition in lithium potassium rubidium sulfate system

NASA Astrophysics Data System (ADS)

Hamed, A. E.; Abd. El-Aziz, Y. M.; Madi, N. K.; Kassem, M. E.

1998-10-01

Specific heat, Cp, measurements have been performed in lithium potassium rubidium sulfate, (Li 0.5- x/2 K 0.5- x/2 Rb x) 2SO 4, system in a wide range of Rb 2SO 4 content ( x) ( x=0 up to x=10%). Measurements were made between 300 and 800 K with special attention paid to the phase transition at 708 K. It is shown that for small contents, ( x), ( x=0.2 up to x=2%) quantitative changes in the temperature dependence of specific heat Cp( T) around the transition point, T1, are observed. A larger content, x, results in essential changes in the critical behavior of Cp( T) and a considerable change in the phase transition accompanied by a progressive decrease in the thermodynamic parameters. The ratios of the Landau expansion coefficients change as the content of Rb 2SO 4 increases.

Frequency control of tunable lasers using a frequency-calibrated λ-meter in an experiment on preparation of Rydberg atoms in a magneto-optical trap

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saakyan, S A; Vilshanskaya, E V; Zelener, B B

2015-09-30

A new technique is proposed and applied to study the frequency drift of an external-cavity semiconductor laser, locked to the transmission resonances of a thermally stabilised Fabry–Perot interferometer. The interferometer frequency drift is measured to be less than 2 MHz h{sup -1}. The laser frequency is measured using an Angstrom wavemeter, calibrated using an additional stabilised laser. It is shown that this system of laser frequency control can be used to identify Rydberg transitions in ultracold {sup 7}Li atoms. (control of laser radiation parameters)

Absolute frequency measurement of the ? optical clock transition in ? with an uncertainty of ? using a frequency link to international atomic time

NASA Astrophysics Data System (ADS)

Baynham, Charles F. A.; Godun, Rachel M.; Jones, Jonathan M.; King, Steven A.; Nisbet-Jones, Peter B. R.; Baynes, Fred; Rolland, Antoine; Baird, Patrick E. G.; Bongs, Kai; Gill, Patrick; Margolis, Helen S.

2018-03-01

The highly forbidden ? electric octupole transition in ? is a potential candidate for a redefinition of the SI second. We present a measurement of the absolute frequency of this optical transition, performed using a frequency link to International Atomic Time to provide traceability to the SI second. The ? optical frequency standard was operated for 76% of a 25-day period, with the absolute frequency measured to be 642 121 496 772 645.14(26) Hz. The fractional uncertainty of ? is comparable to that of the best previously reported measurement, which was made by a direct comparison to local caesium primary frequency standards.

Image routing via atomic spin coherence

PubMed Central

Wang, Lei; Sun, Jia-Xiang; Luo, Meng-Xi; Sun, Yuan-Hang; Wang, Xiao-Xiao; Chen, Yi; Kang, Zhi-Hui; Wang, Hai-Hua; Wu, Jin-Hui; Gao, Jin-Yue

2015-01-01

Coherent storage of optical image in a coherently-driven medium is a promising method with possible applications in many fields. In this work, we experimentally report a controllable spatial-frequency routing of image via atomic spin coherence in a solid-state medium driven by electromagnetically induced transparency (EIT). Under the EIT-based light-storage regime, a transverse spatial image carried by the probe field is stored into atomic spin coherence. By manipulating the frequency and spatial propagation direction of the read control field, the stored image is transferred into a new spatial-frequency channel. When two read control fields are used to retrieve the stored information, the image information is converted into a superposition of two spatial-frequency modes. Through this technique, the image is manipulated coherently and all-optically in a controlled fashion. PMID:26658846

Interpretation of frequency modulation atomic force microscopy in terms of fractional calculus

NASA Astrophysics Data System (ADS)

Sader, John E.; Jarvis, Suzanne P.

2004-07-01

It is widely recognized that small amplitude frequency modulation atomic force microscopy probes the derivative of the interaction force between tip and sample. For large amplitudes, however, such a physical connection is currently lacking, although it has been observed that the frequency shift presents a quantity intermediate to the interaction force and energy for certain force laws. Here we prove that these observations are a universal property of large amplitude frequency modulation atomic force microscopy, by establishing that the frequency shift is proportional to the half-fractional integral of the force, regardless of the force law. This finding indicates that frequency modulation atomic force microscopy can be interpreted as a fractional differential operator, where the order of the derivative/integral is dictated by the oscillation amplitude. We also establish that the measured frequency shift varies systematically from a probe of the force gradient for small oscillation amplitudes, through to the measurement of a quantity intermediate to the force and energy (the half-fractional integral of the force) for large oscillation amplitudes. This has significant implications to measurement sensitivity, since integrating the force will smooth its behavior, while differentiating it will enhance variations. This highlights the importance in choice of oscillation amplitude when wishing to optimize the sensitivity of force spectroscopy measurements to short-range interactions and consequently imaging with the highest possible resolution.

Photoionization Models of Bromine, Rubidium, and Xenon in Planetary Nebulae

NASA Astrophysics Data System (ADS)

Sterling, Nicholas C.; Porter, Ryan; Spencer, Courteney; Sherrard, Cameroun G.

2017-06-01

We present numerical simulations of the Br, Rb, and Xe ionization balance in five planetary nebulae (PNe). These neutron-capture elements (atomic number Z > 30) can be enriched by s-process nucleosynthesis during the asymptotic giant branch (AGB) evolutionary stage of PN progenitor stars. Recent calculations of photoionization cross sections and rate coefficients for radiative recombination, dielectronic recombination, and charge transfer (Kerlin et al. 2017, in preparation; Sterling & Kerlin 2016, 227th AAS, #238.02; Sterling & Stancil 2011, A&A, 535, A117) allow the Br, Rb, and Xe ionization equilibria to be modeled in PNe for the first time. We have added these elements and their atomic data to Cloudy (Ferland et al. 2013, RMxA&A, 49, 137). We model the PNe IC 418, IC 2501, IC 4191, NGC 2440, and NGC 7027, all of which exhibit emission from multiple Xe ions in the optical data of Sharpee et al. (2007, ApJ, 659, 1265). Multiple Br and Rb ions were also detected in NGC 7027. The model central star temperatures and luminosities, and nebular densities, outer radii, and abundances were optimized to best reproduce the observed intensities of Sharpee et al. We find that IC 418 and NGC 7027 are enriched in Br, Rb, and Xe, in accordance with results for Se and Kr (Sterling et al. 2015, ApJS, 218, 25). Given the small sample size and the weakness of the lines involved, it is not clear whether discrepancies between modeled and observed intensities are due to observational, model, or atomic data uncertainties. This sample will be expanded to include other PNe, such as those in our optical survey (Sherrard et al. poster, this session), which will allow us to test the veracity of the new atomic data for Xe and, for a smaller number of PNe, Br and Rb. Following the methods of Sterling et al. (2015), grids of Cloudy models will be computed to derive ionization correction factors for Br, Rb, and Xe for the first time, allowing their abundances to be determined with higher accuracy than previously possible. We acknowledge support from NSF grant AST-1412928.

Embedded dielectric water "atom" array for broadband microwave absorber based on Mie resonance

NASA Astrophysics Data System (ADS)

Gogoi, Dhruba Jyoti; Bhattacharyya, Nidhi Saxena

2017-11-01

A wide band microwave absorber at X-band frequency range is demonstrated numerically and experimentally by embedding a simple rectangular structured dielectric water "atom" in flexible silicone substrate. The absorption peak of the absorber is tuned by manipulating the size of the dielectric water "atom." The frequency dispersive permittivity property of the water "atom" shows broadband absorption covering the entire X-band above 90% efficiency with varying the size of the water "atom." Mie resonance of the proposed absorber provides the desired impedance matching condition at the air-absorber interface across a wide frequency range in terms of electric and magnetic resonances. Multipole decomposition of induced current densities is used to identify the nature of observed resonances. Numerical absorptivity verifies that the designed absorber is polarization insensitive for normal incidence and can maintain an absorption bandwidth of more than 2 GHz in a wide-angle incidence. Additionally, the tunability of absorption property with temperature is shown experimentally.

Influence of the dynamic Stark effect on long-term frequency stability of a self-oscillating magnetometer with laser-pumped alkali atoms

NASA Astrophysics Data System (ADS)

Baranov, A. A.; Ermak, S. V.; Kulachenkov, N. K.; Petrenko, M. V.; Sagitov, E. A.; Semenov, V. V.

2017-11-01

This paper presents the results of investigation Stark shift effect influence on the long-term stability of a dual scheme of quantum magnetometers. Such scheme allows suppressing Stark shift components when a certain pumping light polarization is applied. As a result, long-term stability of a quantum sensor increases. However, when low-frequency (LF) and microwave fields are attached to a single vapor cell a coherence circulation in hyperfine structure of alkali atoms takes place. Physical origin of this effect is associated with the so called “dressed” atom theory, when atom is “dressed” by LF field. It yields in multiphoton absorption and resonance frequency shift. First estimates for this shift based on density matrix evolution formalism are provided in the paper.

Enhancing the low frequency THz resonances (< 1 THz) of organic molecules via electronegative atom substitution

NASA Astrophysics Data System (ADS)

Dash, Jyotirmayee; Ray, Shaumik; Pesala, Bala

2015-03-01

Terahertz (THz) technology is an active area of research with various applications in non-intrusive imaging and spectroscopy. Very few organic molecules have significant resonances below 1 THz. Understanding the origin of low frequency THz modes in these molecules and their absence in other molecules could be extremely important in design and engineering molecules with low frequency THz resonances. These engineered molecules can be used as THz tags for anti-counterfeiting applications. Studies show that low frequency THz resonances are commonly observed in molecules having higher molecular mass and weak intermolecular hydrogen bonds. In this paper, we have explored the possibility of enhancing the strength of THz resonances below 1 THz through electronegative atom substitution. Adding an electronegative atom helps in achieving higher hydrogen bond strength to enhance the resonances below 1 THz. Here acetanilide has been used as a model system. THz-Time Domain Spectroscopy (THz-TDS) results show that acetanilide has a small peak observed below 1 THz. Acetanilide can be converted to 2-fluoroacetanilide by adding an electronegative atom, fluorine, which doesn't have any prominent peak below 1 THz. However, by optimally choosing the position of the electronegative atom as in 4-fluoroacetanilide, a significant THz resonance at 0.86 THz is observed. The origin of low frequency resonances can be understood by carrying out Density Functional Theory (DFT) simulations of full crystal structure. These studies show that adding an electronegative atom to the organic molecules at an optimized position can result in significantly enhanced resonances below 1 THz.

Theory of Wavelet-Based Coarse-Graining Hierarchies for Molecular Dynamics

DTIC Science & Technology

2017-04-01

resolution. ............................................... 15 Fig. 6 Fourier transform of the y-component of 1,000 atoms in crystalline PE (100,800 atoms...of magnitude of optimal representation. . 16 Fig. 7 Top row: Fourier transform of the y-component of a 100,800 atom crystalline PE sampled at 1 fs. 3... transform of the z-component of alanine dipeptide in vacuum excluding zero frequency to allow detail at other frequencies. MD at 500 K and 1 atm. Left

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Bo; Zhao, Hongwei, E-mail: hwzhao@jlu.edu.cn, E-mail: khl69@163.com; Zhao, Dan

It has always been a critical issue to understand the material removal behavior of Vibration-Assisted Machining (VAM), especially on atomic level. To find out the effects of vibration frequency on material removal response, a three-dimensional molecular dynamics (MD) model has been established in this research to investigate the effects of scratched groove, crystal defects on the surface quality, comparing with the Von Mises shear strain and tangential force in simulations during nano-scratching process. Comparisons are made among the results of simulations from different vibration frequency with the same scratching feed, depth, amplitude and crystal orientation. Copper potential in this simulationmore » is Embedded-Atom Method (EAM) potential. Interaction between copper and carbon atoms is Morse potential. Simulational results show that higher frequency can make groove smoother. Simulation with high frequency creates more dislocations to improve the machinability of copper specimen. The changing frequency does not have evident effects on Von Mises shear strain. Higher frequency can decrease the tangential force to reduce the consumption of cutting energy and tool wear. In conclusion, higher vibration frequency in VAM on mono-crystalline copper has positive effects on surface finish, machinablility and tool wear reduction.« less

Direct frequency comb optical frequency standard based on two-photon transitions of thermal atoms

PubMed Central

Zhang, S. Y.; Wu, J. T.; Zhang, Y. L.; Leng, J. X.; Yang, W. P.; Zhang, Z. G.; Zhao, J. Y.

2015-01-01

Optical clocks have been the focus of science and technology research areas due to their capability to provide highest frequency accuracy and stability to date. Their superior frequency performance promises significant advances in the fields of fundamental research as well as practical applications including satellite-based navigation and ranging. In traditional optical clocks, ultrastable optical cavities, laser cooling and particle (atoms or a single ion) trapping techniques are employed to guarantee high stability and accuracy. However, on the other hand, they make optical clocks an entire optical tableful of equipment, and cannot work continuously for a long time; as a result, they restrict optical clocks used as very convenient and compact time-keeping clocks. In this article, we proposed, and experimentally demonstrated, a novel scheme of optical frequency standard based on comb-directly-excited atomic two-photon transitions. By taking advantage of the natural properties of the comb and two-photon transitions, this frequency standard achieves a simplified structure, high robustness as well as decent frequency stability, which promise widespread applications in various scenarios. PMID:26459877

One Photon Can Simultaneously Excite Two or More Atoms.

PubMed

Garziano, Luigi; Macrì, Vincenzo; Stassi, Roberto; Di Stefano, Omar; Nori, Franco; Savasta, Salvatore

2016-07-22

We consider two separate atoms interacting with a single-mode optical or microwave resonator. When the frequency of the resonator field is twice the atomic transition frequency, we show that there exists a resonant coupling between one photon and two atoms, via intermediate virtual states connected by counterrotating processes. If the resonator is prepared in its one-photon state, the photon can be jointly absorbed by the two atoms in their ground state which will both reach their excited state with a probability close to one. Like ordinary quantum Rabi oscillations, this process is coherent and reversible, so that two atoms in their excited state will undergo a downward transition jointly emitting a single cavity photon. This joint absorption and emission process can also occur with three atoms. The parameters used to investigate this process correspond to experimentally demonstrated values in circuit quantum electrodynamics systems.

Compact atom interferometer using single laser

NASA Astrophysics Data System (ADS)

Chiow, Sheng-wey; Yu, Nan

2018-06-01

A typical atom interferometer requires vastly different laser frequencies at different stages of operation, e.g., near resonant light for laser cooling and far detuned light for atom optics, such that multiple lasers are typically employed. The number of laser units constrains the achievable minimum size and power in practical devices for resource critical environments such as space. We demonstrate a compact atom interferometer accelerometer operated by a single diode laser. This is achieved by dynamically changing the laser output frequency in GHz range while maintaining spectroscopic reference to an atomic transition via a sideband generated by phase modulation. At the same time, a beam path sharing configuration is also demonstrated for a compact sensor head design, in which atom interferometer beams share the same path as that of the cooling beam. This beam path sharing also significantly simplifies three-axis atomic accelerometry in microgravity using single sensor head.

NASA atomic hydrogen standards program: An update

NASA Technical Reports Server (NTRS)

Reinhardt, V. S.; Kaufmann, D. C.; Adams, W. A.; Deluca, J. J.; Soucy, J. L.

1976-01-01

Comparisons are made between the NP series and the NX series of hydrogen masers. A field operable hydrogen maser (NR series) is also described. Atomic hydrogen primary frequency standards are in development stages. Standards are being developed for a hydrogen beam frequency standard and for a concertina hydrogen maser.

Phase modulation for reduced vibration sensitivity in laser-cooled clocks in space

NASA Technical Reports Server (NTRS)

Klipstein, W.; Dick, G.; Jefferts, S.; Walls, F.

2001-01-01

The standard interrogation technique in atomic beam clocks is square-wave frequency modulation (SWFM), which suffers a first order sensitivity to vibrations as changes in the transit time of the atoms translates to perceived frequency errors. Square-wave phase modulation (SWPM) interrogation eliminates sensitivity to this noise.

A compact micro-wave synthesizer for transportable cold-atom interferometers

NASA Astrophysics Data System (ADS)

Lautier, J.; Lours, M.; Landragin, A.

2014-06-01

We present the realization of a compact micro-wave frequency synthesizer for an atom interferometer based on stimulated Raman transitions, applied to transportable inertial sensing. Our set-up is intended to address the hyperfine transitions of 87Rb at 6.8 GHz. The prototype is evaluated both in the time and the frequency domain by comparison with state-of-the-art frequency references developed at Laboratoire national de métrologie et d'essais-Systémes de référence temps espace (LNE-SYRTE). In free-running mode, it features a residual phase noise level of -65 dB rad2 Hz-1 at 10 Hz offset frequency and a white phase noise level in the order of -120 dB rad2 Hz-1 for Fourier frequencies above 10 kHz. The phase noise effect on the sensitivity of the atomic interferometer is evaluated for diverse values of cycling time, interrogation time, and Raman pulse duration. To our knowledge, the resulting contribution is well below the sensitivity of any demonstrated cold atom inertial sensors based on stimulated Raman transitions. The drastic improvement in terms of size, simplicity, and power consumption paves the way towards field and mobile operations.

The impact of prompt gamma compensation on myocardial blood flow measurements with rubidium-82 dynamic PET.

PubMed

Armstrong, Ian S; Memmott, Matthew J; Tonge, Christine M; Arumugam, Parthiban

2018-04-01

Rubidium-82 myocardial perfusion imaging is a well-established technique for assessing myocardial ischemia. With continuing interest on myocardial blood flow (MBF) and myocardial flow reserve (MFR) measurements, there is a requirement to fully appreciate the impact of technical aspects of the process. One such factor for rubidium-82 is prompt gamma compensation (PGC). This study aims to assess the impact of PGC on MBF and MFR calculated from dynamic Rb-82 data. Dynamic rest and stress images were acquired on a Siemens Biograph mCT and reconstructed with and without PGC in 50 patients (29 male). MBF and MFR were measured in the three main coronary territories as well as globally. With PGC, statistically significant reductions in MBF were observed in LAD (-6.9%), LCx (-4.8%), and globally (-6.5%) but only in obese patients. Significant increases in MBF were observed in RCA (+6.4%) in only nonobese patients. In very obese patients, differences of up to 40% in MBF were observed between PGC and non-PGC images. In nearly all cases, similar PGC differences were observed at stress and rest so there were no significant differences in MFR; however, in a small number of very obese patients, differences in excess of 20% were observed. PGC results in statistically significant changes in MBF, with the greatest reductions observed in the LAD and LCx territories of obese patients. In most cases, the impact on stress and rest data is of similar relative magnitudes and changes to MFR are small.

Progress towards a cesium atomic fountain clock

NASA Astrophysics Data System (ADS)

Klipstein, William M.; Raithel, Georg A.; Rolston, Steven L.; Phillips, William D.; Ekstrom, Christopher R.

1997-04-01

We have been developing a fountain of laser--cooled cesium atoms for use as an atomic clock. Our design largely follows that of the fountain built at LPTF in Paris. In our fountain, chirp--slowed atoms are first collected in a Magneto--Optic Trap (MOT) and then cooled to a few μK in optical molasses. The cooled atoms are then launched vertically into a "moving molasses" by shifting the frequencies of the vertical cooling beams. The atoms then travel through a microwave cavity tuned to the 9.2 GHz cesium hyperfine frequency for a first Ramsey pulse. After roughly 0.5 seconds of free flight under the influence of gravity, the atoms fall back through the microwave cavity and into an optical state--detection region which detects the number of atoms making the F=3 arrow F=4 transition. The increased Ramsey interaction time improves the short--time precision as compared to traditional atomic beam experiments, while many systematic shifts which limit the accuracy of an atomic beam clock are reduced by the low atomic velocity and the retrace of the atomic trajectory through the microwave cavity. We will discuss the progress towards a working fountain being assembled in our laboratory.

Time and frequency applications.

PubMed

Hellwig, H

1993-01-01

An overview is given of the capabilities of atomic clocks and quartz crystal oscillators in terms of available precision of time and frequency signals. The generation, comparison, and dissemination of time and frequency is then discussed. The principal focus is to survey uses of time and frequency in navigation, communication, and science. The examples given include the Global Positioning System, a satellite-based global navigation system, and general and dedicated communication networks, as well as experiments in general relativity and radioastronomy. The number of atomic clocks and crystal oscillators that are in actual use worldwide is estimated.

Observation of the Rabi oscillation of light driven by an atomic spin wave.

PubMed

Chen, L Q; Zhang, Guo-Wan; Bian, Cheng-Ling; Yuan, Chun-Hua; Ou, Z Y; Zhang, Weiping

2010-09-24

Coherent conversion between a Raman pump field and its Stokes field is observed in a Raman process with a strong atomic spin wave initially prepared by another Raman process operated in the stimulated emission regime. The oscillatory behavior resembles the Rabi oscillation in atomic population in a two-level atomic system driven by a strong light field. The Rabi-like oscillation frequency is found to be related to the strength of the prebuilt atomic spin wave. High conversion efficiency of 40% from the Raman pump field to the Stokes field is recorded and it is independent of the input Raman pump field. This process can act as a photon frequency multiplexer and may find wide applications in quantum information science.

Noise squeezing of fields that bichromatically excite atoms in a cavity.

PubMed

Li, Lingchao; Hu, Xiangming; Rao, Shi; Xu, Jun

2016-11-14

It is well known that bichromatic excitation on one common transition can tune the emission or absorption spectra of atoms due to the modulation frequency dependent non-linearities. However little attention has been focused on the quantum dynamics of fields under bichromatic excitation. Here we present dissipative effects on noise correlations of fields in bichromatic interactions with atoms in cavities. We first consider an ensemble of two-level atoms that interacts with the two cavity fields of different frequencies and considerable amplitudes. By transferring the atom-field nonlinearities to the dressed atoms we separate out the dissipative interactions of Bogoliubov modes with the dressed atoms. The Bogoliubov mode dissipation establishes stable two-photon processes of two involved fields and therefore leads to two-mode squeezing. As a generalization, we then consider an ensemble of three-level Λ atoms for cascade bichromatic interactions. We extract the Bogoliubov-like four-mode interactions, which establish a quadrilateral of the two-photon processes of four involved fields and thus result in four-mode squeezing.

Evidence for Chemical and Electronic Nonuniformities in the Formation of the Interface of RbF-Treated Cu(In,Ga)Se2 with CdS.

PubMed

Nicoara, Nicoleta; Kunze, Thomas; Jackson, Philip; Hariskos, Dimitrios; Duarte, Roberto Félix; Wilks, Regan G; Witte, Wolfram; Bär, Marcus; Sadewasser, Sascha

2017-12-20

We report on the initial stages of CdS buffer layer formation on Cu(In,Ga)Se 2 (CIGSe) thin-film solar cell absorbers subjected to rubidium fluoride (RbF) postdeposition treatment (PDT). A detailed characterization of the CIGSe/CdS interface for different chemical bath deposition (CBD) times of the CdS layer is obtained from spatially resolved atomic and Kelvin probe force microscopy and laterally integrating X-ray spectroscopies. The observed spatial inhomogeneity in the interface's structural, chemical, and electronic properties of samples undergoing up to 3 min of CBD treatments is indicative of a complex interface formation including an incomplete coverage and/or nonuniform composition of the buffer layer. It is expected that this result impacts solar cell performance, in particular when reducing the CdS layer thickness (e.g., in an attempt to increase the collection in the ultraviolet wavelength region). Our work provides important findings on the absorber/buffer interface formation and reveals the underlying mechanism for limitations in the reduction of the CdS thickness, even when an alkali PDT is applied to the CIGSe absorber.

Methods for collection and analysis of geopressured geothermal and oil field waters

USGS Publications Warehouse

Lico, Michael S.; Kharaka, Yousif K.; Carothers, William W.; Wright, Victoria A.

1982-01-01

Present methods are described for the collection, preservation, and chemical analysis of waters produced from geopressured geothermal and petroleum wells. Detailed procedures for collection include precautions and equipment necessary to ensure that the sample is representative of the water produced. Procedures for sample preservation include filtration, acidification, dilution for silica, methyl isobutyl ketone (MIBK) extraction of aluminum, addition of potassium permanganate to preserve mercury, and precipitation of carbonate species as strontium carbonate for stable carbon isotopes and total dissolved carbonate analysis. Characteristics determined at the well site are sulfide, pH, ammonia, and conductivity. Laboratory procedures are given for the analysis of lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, iron, manganese, zinc, lead, aluminum, .and mercury by atomic absorption and flame emission spectroscopy. Chloride is determined by silver nitrate titration and fluoride by ion-specific electrode. Bromide and iodide concentrations are determined by the hypochlorite oxidation method. Sulfate is analyzed by titration using barium chloride with thorin indicator after pretreatment with alumina. Boron and silica are determined colorimetrically by the carmine and molybdate-blue methods, respectively. Aliphatic acid anions (C2 through C5) are determined by gas chromatography after separation and concentration in a chloroform-butanol mixture.

First principles study of structural, electronic and optical properties of polymorphic forms of Rb 2Te

NASA Astrophysics Data System (ADS)

Alay-e-Abbas, S. M.; Shaukat, A.

2011-05-01

First-principles density functional theory calculations have been performed for structural, electronic and optical properties of three polymorphic forms of rubidium telluride. Our calculations show that the sequence of pressure induced phase transitions for Rb 2Te is Fm3¯m → Pnma → P6 3/mmc which is governed by the coordination numbers of the anions. From our calculated low transition pressure value for the Fm3¯m phase to the Pnma phase transition of Rb 2Te, the experimentally observed meta-stability of Fm3¯m phase at ambient conditions seems reasonable. The electronic band structure has been calculated for all the three phases and the change in the energy band gap is discussed for the transitioning phases. The energy band gaps obtained for the three phases of Rb 2Te decrease on going from the meta-stable phase to the high-pressure phases. Total and partial density of states for the polymorphs of Rb 2Te has been computed to elucidate the contribution of various atomic states on the electronic band structure. Furthermore, optical properties for all the polymorphic forms have been presented in form of the complex dielectric function.

Ultradispersive adaptive prism based on a coherently prepared atomic medium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sautenkov, Vladimir A.; P. N. Lebedev Institute of Physics, Moscow 119991; Li Hebin

2010-06-15

We have experimentally demonstrated an ultra-dispersive optical prism made from a coherently driven Rb atomic vapor. The prism possesses spectral angular dispersion that is 6 orders of magnitude higher than that of a prism made of optical glass; such angular dispersion allows one to spatially resolve light beams with different frequencies separated by a few kilohertz. The prism operates near the resonant frequency of atomic vapor and its dispersion is optically controlled by a coherent driving field.

Power Play, Laser Style

NASA Technical Reports Server (NTRS)

1998-01-01

Under a NASA SBIR (Small Business Innovation Research) SDL, Inc., has developed the TC40 Single-Frequency Continuously Tunable 500 mw Laser Diode System. This is the first commercially available single frequency diode laser system that offers the broad tunability and the high powers needed for atomic cooling and trapping as well as a variety of atomic spectroscopy techniques. By greatly decreasing both the equipment and the costs of entry, the TC40 enables researchers to pursue some of the most interesting areas of physical chemistry, biochemistry, and atomic physics.

Mass defect effects in atomic clocks

NASA Astrophysics Data System (ADS)

Yudin, Valeriy; Taichenachev, Alexey

2018-03-01

We consider some implications of the mass defect on the frequency of atomic transitions. We have found that some well-known frequency shifts (the gravitational shift and motion-induced shifts such as quadratic Doppler and micromotion shifts) can be interpreted as consequences of the mass defect in quantum atomic physics, i.e. without the need for the concept of time dilation used in special and general relativity theories. Moreover, we show that the inclusion of the mass defect leads to previously unknown shifts for clocks based on trapped ions.

Chirped-Pulse Millimeter-Wave Spectroscopy of Rydberg-Rydberg Transitions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prozument, Kirill; Colombo, Anthony P.; Zhou Yan

2011-09-30

Transitions between Rydberg states of Ca atoms, in a pulsed, supersonic atomic beam, are directly detected by chirped-pulse millimeter-wave spectroscopy. Broadband, high-resolution spectra with accurate relative intensities are recorded instantly. Free induction decay (FID) of atoms, polarized by the chirped pulse, at their Rydberg-Rydberg transition frequencies, is heterodyne detected, averaged in the time domain, and Fourier transformed into the frequency domain. Millimeter-wave transient nutations are observed, and the possibility of FID evolving to superradiance is discussed.

Coherent storage of temporally multimode light using a spin-wave atomic frequency comb memory

NASA Astrophysics Data System (ADS)

Gündoǧan, M.; Mazzera, M.; Ledingham, P. M.; Cristiani, M.; de Riedmatten, H.

2013-04-01

We report on the coherent and multi-temporal mode storage of light using the full atomic frequency comb memory scheme. The scheme involves the transfer of optical atomic excitations in Pr3+:Y2SiO5 to spin waves in hyperfine levels using strong single-frequency transfer pulses. Using this scheme, a total of five temporal modes are stored and recalled on-demand from the memory. The coherence of the storage and retrieval is characterized using a time-bin interference measurement resulting in visibilities higher than 80%, independent of the storage time. This coherent and multimode spin-wave memory is promising as a quantum memory for light.

Frequency standards based on ultracold atoms in tests of general relativity, navigation and gravimetry

NASA Astrophysics Data System (ADS)

Khabarova, K. Yu.; Kudeyarov, K. S.; Kolachevsky, N. N.

2017-06-01

Research and development in the field of optical clocks based on ultracold atoms and ions have enabled the relative uncertainty in frequency to be reduced down to a few parts in 1018. The use of novel, precise frequency comparison methods opens up new possibilities for basic research (sensitive tests of general relativity, a search for a drift of fundamental constants and a search for ‘dark matter’) as well as for state-of-the-art navigation and gravimetry. We discuss the key methods that are used in creating precision clocks (including transportable clocks) based on ultracold atoms and ions and the feasibility of using them in resolving current relativistic gravimetry issues.

The color bar phase meter: A simple and economical method for calibrating crystal oscillators

NASA Technical Reports Server (NTRS)

Davis, D. D.

1973-01-01

Comparison of crystal oscillators to the rubidium stabilized color burst is made easy and inexpensive by use of the color bar phase meter. Required equipment consists of an unmodified color TV receiver, a color bar synthesizer and a stop watch (a wrist watch or clock with sweep second hand may be used with reduced precision). Measurement precision of 1 x 10 to the minus 10th power can be realized in measurement times of less than two minutes. If the color bar synthesizer were commercially available, user cost should be less than $200.00, exclusive of the TV receiver. Parts cost for the color bar synthesizer which translates the crystal oscillator frequency to 3.579MHz and modulates the received RF signal before it is fed to the receiver antenna terminals is about $25.00. A more sophisticated automated version, with precision of 1 x 10 to the minus 11th power would cost about twice as much.

Pressure effect on phonon frequencies in some transition metals: A molecular dynamics study

NASA Astrophysics Data System (ADS)

Kazanc, S.; Ozgen, S.

2005-08-01

It is important to determine the atomic lattice vibrations of metallic materials, under high-pressure conditions, due to its effects on material properties such as thermal, electrical and optical conductions. In this work, we have investigated the changes of acoustic phonon frequencies with hydrostatic pressure for Cu, Ni, Al, Ag and Au transition metals, using molecular dynamics (MD) simulations based on embedded atom method (EAM). For this aim, we have adopted the embedded atom potential proposed by Sutton and Chen. The phonon frequencies have been calculated from the dynamical matrix for [1 0 0], [1 1 0] and [1 1 1] high symmetry directions of the Brillouin zone. The obtained results show that the hydrostatic pressure causes an increment in phonon frequencies, and this rising do not depend linearly on the increasing pressure.

Diode laser operating on an atomic transition limited by an isotope ⁸⁷Rb Faraday filter at 780 nm.

PubMed

Tao, Zhiming; Hong, Yelong; Luo, Bin; Chen, Jingbiao; Guo, Hong

2015-09-15

We demonstrate an extended cavity Faraday laser system using an antireflection-coated laser diode as the gain medium and the isotope (87)Rb Faraday anomalous dispersion optical filter (FADOF) as the frequency selective device. Using this method, the laser wavelength works stably at the highest transmission peak of the isotope (87)Rb FADOF over the laser diode current from 55 to 140 mA and the temperature from 15°C to 35°C. Neither the current nor the temperature of the laser diode has significant influence on the output frequency. Compared with previous extended cavity laser systems operating at frequencies irrelevant to spectacular atomic transition lines, the laser system realized here provides a stable laser source with the frequency operating on atomic transitions for many practical applications.

First uncertainty evaluation of the FoCS-2 primary frequency standard

NASA Astrophysics Data System (ADS)

Jallageas, A.; Devenoges, L.; Petersen, M.; Morel, J.; Bernier, L. G.; Schenker, D.; Thomann, P.; Südmeyer, T.

2018-06-01

We report the uncertainty evaluation of the Swiss continuous primary frequency standard FoCS-2 (Fontaine Continue Suisse). Unlike other primary frequency standards which are working with clouds of cold atoms, this fountain uses a continuous beam of cold caesium atoms bringing a series of metrological advantages and specific techniques for the evaluation of the uncertainty budget. Recent improvements of FoCS-2 have made possible the evaluation of the frequency shifts and of their uncertainties in the order of . When operating in an optimal regime a relative frequency instability of is obtained. The relative standard uncertainty reported in this article, , is strongly dominated by the statistics of the frequency measurements.

Photon Shot Noise Limited Radio Frequency Electric Field Sensing Using Rydberg Atoms in Vapor Cells

NASA Astrophysics Data System (ADS)

Kumar, Santosh; Jahangiri, Akbar J.; Fan, Haoquan; Kuebler, Harald; Shaffer, James P.

2017-04-01

We report Rydberg atom-based radio frequency (RF) electrometry measurements at a sensitivity limited by probe laser photon shot noise. By utilizing the phenomena of electromagnetically induced transparency (EIT) in room temperature atomic vapor cells, Rydberg atoms can be used for absolute electric field measurements that significantly surpass conventional methods in utility, sensitivity and accuracy. We show that by using a Mach-Zehnder interferometer with homodyne detection or using frequency modulation spectroscopy with active control of residual amplitude modulation we can achieve a RF electric field detection sensitivity of 3 μVcm-1Hz/2. The sensitivity is limited by photon shot noise on the detector used to readout the probe laser of the EIT scheme. We suggest a new multi-photon scheme that can mitigate the effect of photon shot noise. The multi-photon approach allows an increase in probe laser power without decreasing atomic coherence times that result from collisions caused by an increase in Rydberg atom excitation. The multi-photon scheme also reduces Residual Doppler broadening enabling more accurate measurements to be carried out. This work is supported by DARPA, and NRO.

Laser-cooled cesium fountain clock: design and expected performances

NASA Astrophysics Data System (ADS)

Clairon, Andre; Laurent, Phillipe; Nadir, A.; Santarelli, G.; Drewsen, M.; Grison, D.; Lounis, B.; Salomon, C.

1993-04-01

The use of diode lasers to cool and trap Cesium atoms in a low Cs pressure cell allows the construction of a relatively simple and reliable atomic fountain frequency standard. Here we discuss the design and the potentialities of the Cs clock frequency standards being built at L.P.T.F..

A programmable broadband low frequency active vibration isolation system for atom interferometry.

PubMed

Tang, Biao; Zhou, Lin; Xiong, Zongyuan; Wang, Jin; Zhan, Mingsheng

2014-09-01

Vibration isolation at low frequency is important for some precision measurement experiments that use atom interferometry. To decrease the vibrational noise caused by the reflecting mirror of Raman beams in atom interferometry, we designed and demonstrated a compact stable active low frequency vibration isolation system. In this system, a digital control subsystem is used to process and feedback the vibration measured by a seismometer. A voice coil actuator is used to control and cancel the motion of a commercial passive vibration isolation platform. With the help of field programmable gate array-based control subsystem, the vibration isolation system performed flexibly and accurately. When the feedback is on, the intrinsic resonance frequency of the system will change from 0.8 Hz to about 0.015 Hz. The vertical vibration (0.01-10 Hz) measured by the in-loop seismometer is reduced by an additional factor of up to 500 on the basis of a passive vibration isolation platform, and we have proved the performance by adding an additional seismometer as well as applying it in the atom interferometry experiment.

Parametric Time-Frequency Analysis and Its Applications in Music Classification

NASA Astrophysics Data System (ADS)

Shen, Ying; Li, Xiaoli; Ma, Ngok-Wah; Krishnan, Sridhar

2010-12-01

Analysis of nonstationary signals, such as music signals, is a challenging task. The purpose of this study is to explore an efficient and powerful technique to analyze and classify music signals in higher frequency range (44.1 kHz). The pursuit methods are good tools for this purpose, but they aimed at representing the signals rather than classifying them as in Y. Paragakin et al., 2009. Among the pursuit methods, matching pursuit (MP), an adaptive true nonstationary time-frequency signal analysis tool, is applied for music classification. First, MP decomposes the sample signals into time-frequency functions or atoms. Atom parameters are then analyzed and manipulated, and discriminant features are extracted from atom parameters. Besides the parameters obtained using MP, an additional feature, central energy, is also derived. Linear discriminant analysis and the leave-one-out method are used to evaluate the classification accuracy rate for different feature sets. The study is one of the very few works that analyze atoms statistically and extract discriminant features directly from the parameters. From our experiments, it is evident that the MP algorithm with the Gabor dictionary decomposes nonstationary signals, such as music signals, into atoms in which the parameters contain strong discriminant information sufficient for accurate and efficient signal classifications.

A Theoretical Model Analysis of Absorption of a Three level Diode Pumped Alkali Laser

DTIC Science & Technology

2009-03-01

2.10) 103 Bibliography Demtroder, Wolfgang . Laser Spectroscopy: Basic Concepts and Instrumentation. Berlin: Springer...Konefal Z., “Observation of collision induced processes in rubidium-ethane vapour,” Optics Communication, 164:95-105 (1999). Krause , L

The Coulombic Lattice Potential of Ionic Compounds: The Cubic Perovskites.

ERIC Educational Resources Information Center

Francisco, E.; And Others

1988-01-01

Presents coulombic models representing the particles of a system by point charges interacting through Coulomb's law to explain coulombic lattice potential. Uses rubidium manganese trifluoride as an example of cubic perovskite structure. Discusses the effects on cluster properties. (CW)

Adaptive phase extraction: incorporating the Gabor transform in the matching pursuit algorithm.

PubMed

Wacker, Matthias; Witte, Herbert

2011-10-01

Short-time Fourier transform (STFT), Gabor transform (GT), wavelet transform (WT), and the Wigner-Ville distribution (WVD) are just some examples of time-frequency analysis methods which are frequently applied in biomedical signal analysis. However, all of these methods have their individual drawbacks. The STFT, GT, and WT have a time-frequency resolution that is determined by algorithm parameters and the WVD is contaminated by cross terms. In 1993, Mallat and Zhang introduced the matching pursuit (MP) algorithm that decomposes a signal into a sum of atoms and uses a cross-term free pseudo-WVD to generate a data-adaptive power distribution in the time-frequency space. Thus, it solved some of the problems of the GT and WT but lacks phase information that is crucial e.g., for synchronization analysis. We introduce a new time-frequency analysis method that combines the MP with a pseudo-GT. Therefore, the signal is decomposed into a set of Gabor atoms. Afterward, each atom is analyzed with a Gabor analysis, where the time-domain gaussian window of the analysis matches that of the specific atom envelope. A superposition of the single time-frequency planes gives the final result. This is the first time that a complete analysis of the complex time-frequency plane can be performed in a fully data-adaptive and frequency-selective manner. We demonstrate the capabilities of our approach on a simulation and on real-life magnetoencephalogram data.

Component-Level Demonstration of a Microfabricated Atomic Frequency Reference

DTIC Science & Technology

2005-08-01

Kitching, L. A. Liew, and J. Moreland, "A microfabricated atomic clock," Applied Physics Letters, vol. 85, pp. 1460-1462, 2004. [4] R. Lutwak , P...Symposium on Frequency Standards and Metrology, P. Gill, Ed. St. Andrews, Scotland: World Scientific, 2001, pp. 155-166. [31] R. Lutwak , D. Emmons...Frequency and Time Forum. Tampa, FL, 2003, pp. 31-32. [71] R. Lutwak , D. Emmons, T. English, W. Riley, A. Duwel, M. Varghese, D. K. Serkland, and

A low phase noise microwave frequency synthesis for a high-performance cesium vapor cell atomic clock

DOE Office of Scientific and Technical Information (OSTI.GOV)

François, B.; Boudot, R.; Calosso, C. E.

2014-09-15

We report the development, absolute phase noise, and residual phase noise characterization of a 9.192 GHz microwave frequency synthesis chain devoted to be used as a local oscillator in a high-performance cesium vapor cell atomic clock based on coherent population trapping (CPT). It is based on frequency multiplication of an ultra-low phase noise 100 MHz oven-controlled quartz crystal oscillator using a nonlinear transmission line-based chain. Absolute phase noise performances of the 9.192 GHz output signal are measured to be −42, −100, −117 dB rad{sup 2}/Hz and −129 dB rad{sup 2}/Hz at 1 Hz, 100 Hz, 1 kHz, and 10 kHz offset frequencies, respectively. Comparedmore » to current results obtained in a state-of-the-art CPT-based frequency standard developed at LNE-SYRTE, this represents an improvement of 8 dB and 10 dB at f = 166 Hz and f = 10 kHz, respectively. With such performances, the expected Dick effect contribution to the atomic clock short term frequency stability is reported at a level of 6.2 × 10{sup −14} at 1 s integration time, that is a factor 3 higher than the atomic clock shot noise limit. Main limitations are pointed out.« less

Atomistic modeling of the low-frequency mechanical modes and Raman spectra of icosahedral virus capsids

NASA Astrophysics Data System (ADS)

Dykeman, Eric C.; Sankey, Otto F.

2010-02-01

We describe a technique for calculating the low-frequency mechanical modes and frequencies of a large symmetric biological molecule where the eigenvectors of the Hessian matrix are determined with full atomic detail. The method, which follows order N methods used in electronic structure theory, determines the subset of lowest-frequency modes while using group theory to reduce the complexity of the problem. We apply the method to three icosahedral viruses of various T numbers and sizes; the human viruses polio and hepatitis B, and the cowpea chlorotic mottle virus, a plant virus. From the normal-mode eigenvectors, we use a bond polarizability model to predict a low-frequency Raman scattering profile for the viruses. The full atomic detail in the displacement patterns combined with an empirical potential-energy model allows a comparison of the fully atomic normal modes with elastic network models and normal-mode analysis with only dihedral degrees of freedom. We find that coarse-graining normal-mode analysis (particularly the elastic network model) can predict the displacement patterns for the first few (˜10) low-frequency modes that are global and cooperative.

Quasistatic limit of the strong-field approximation describing atoms in intense laser fields: Circular polarization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauer, Jaroslaw H.

2011-03-15

In the recent work of Vanne and Saenz [Phys. Rev. A 75, 063403 (2007)] the quasistatic limit of the velocity gauge strong-field approximation describing the ionization rate of atomic or molecular systems exposed to linearly polarized laser fields was derived. It was shown that in the low-frequency limit the ionization rate is proportional to the laser frequency {omega} (for a constant intensity of the laser field). In the present work I show that for circularly polarized laser fields the ionization rate is proportional to {omega}{sup 4} for H(1s) and H(2s) atoms, to {omega}{sup 6} for H(2p{sub x}) and H(2p{sub y})more » atoms, and to {omega}{sup 8} for H(2p{sub z}) atoms. The analytical expressions for asymptotic ionization rates (which become nearly accurate in the limit {omega}{yields}0) contain no summations over multiphoton contributions. For very low laser frequencies (optical or infrared) these expressions usually remain with an order-of-magnitude agreement with the velocity gauge strong-field approximation.« less

Accurate and agile digital control of optical phase, amplitude and frequency for coherent atomic manipulation of atomic systems.

PubMed

Thom, Joseph; Wilpers, Guido; Riis, Erling; Sinclair, Alastair G

2013-08-12

We demonstrate a system for fast and agile digital control of laser phase, amplitude and frequency for applications in coherent atomic systems. The full versatility of a direct digital synthesis radiofrequency source is faithfully transferred to laser radiation via acousto-optic modulation. Optical beatnotes are used to measure phase steps up to 2π, which are accurately implemented with a resolution of ≤ 10 mrad. By linearizing the optical modulation process, amplitude-shaped pulses of durations ranging from 500 ns to 500 ms, in excellent agreement with the programmed functional form, are demonstrated. Pulse durations are limited only by the 30 ns rise time of the modulation process, and a measured extinction ratio of > 5 × 10(11) is achieved. The system presented here was developed specifically for controlling the quantum state of trapped ions with sequences of multiple laser pulses, including composite and bichromatic pulses. The demonstrated techniques are widely applicable to other atomic systems ranging across quantum information processing, frequency metrology, atom interferometry, and single-photon generation.

Low frequency mechanical modes of viruses with atomic detail

NASA Astrophysics Data System (ADS)

Dykeman, Eric; Sankey, Otto

2008-03-01

The low frequency mechanical modes of viruses can provide important insights into the large global motions that a virus may exhibit. Recently it has been proposed that these large global motions may be excited using impulsive stimulated Raman scattering producing permanent damage to the virus. In order to understand the coupling of external probes to the capsid, vibrational modes with atomic detail are essential. The standard approach to find the atomic modes of a molecule with N atoms requires the formation and diagonlization of a 3Nx3N matrix. As viruses have 10^5 or more atoms, the standard approach is difficult. Using ideas from electronic structure theory, we have developed a method to construct the mechanical modes of large molecules such as viruses with atomic detail. Application to viruses such as the cowpea chlorotic mottle virus, satellite tobacco necrosis virus, and M13 bacteriophage show a fairly complicated picture of the mechanical modes.

Quenches across the self-organization transition in multimode cavities

NASA Astrophysics Data System (ADS)

Keller, Tim; Torggler, Valentin; Jäger, Simon B.; Schütz, Stefan; Ritsch, Helmut; Morigi, Giovanna

2018-02-01

A cold dilute atomic gas in an optical resonator can be radiatively cooled by coherent scattering processes when the driving laser frequency is tuned close to but below the cavity resonance. When the atoms are sufficiently illuminated, their steady state undergoes a phase transition from a homogeneous distribution to a spatially organized Bragg grating. We characterize the dynamics of this self-ordering process in the semi-classical regime when distinct cavity modes with commensurate wavelengths are quasi-resonantly driven by laser fields via scattering by the atoms. The lasers are simultaneously applied and uniformly illuminate the atoms; their frequencies are chosen so that the atoms are cooled by the radiative processes, and their intensities are either suddenly switched or slowly ramped across the self-ordering transition. Numerical simulations for different ramp protocols predict that the system will exhibit long-lived metastable states, whose occurrence strongly depends on the initial temperature, ramp speed, and the number of atoms.

Realization of a twin beam source based on four-wave mixing in Cesium

NASA Astrophysics Data System (ADS)

Adenier, G.; Calonico, D.; Micalizio, S.; Samantaray, N.; Degiovanni, I. P.; Berchera, I. Ruo

2016-05-01

Four-wave mixing (4WM) is a known source of intense non-classical twin beams. It can be generated when an intense laser beam (the pump) and a weak laser beam (the seed) overlap in a χ(3) medium (here Cesium vapor), with frequencies close to resonance with atomic transitions. The twin beams generated by 4WM have frequencies naturally close to atomic transitions, and can be intense (gain ≫1) even in the CW pump regime, which is not the case for PDC χ(2) phenomenon in nonlinear crystals. So, 4WM is well suited for atom-light interaction and atom-based quantum-protocols. Here, we present the first realization of a source of 4-wave mixing exploiting D2 line of Cesium atoms.

Immune responses to epstein-barr virus in atomic bomb survivors: Study of precursor frequency of cytotoxic lymphocytes and titer levels of anti-Epstein-Barr virus-related antibodies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kusunoki, Yoichiro; Kyoizumi, Seishi; Saito, Mayumi

Precursor frequencies of cytotoxic lymphocytes to autologous Epstein-Barr virus-transformed B cells and serum titers of anti-Epstein-Barr virus-related antibodies were measured in 68 atomic bomb survivors to clarify the immune mechanism controlling Epstein-Barr virus infection. The precursor frequency was negatively correlated with the titer of anti-early antigen lgG, which is probably produced at the stage of viral reactivation. A positive correlation between the precursor frequency and titer of anti-Epstein-Barr virus-associated nuclear antigen antibody was also observed, indicating that the precursor frequency reflects the degree of in vivo destruction by T cells of the virus-infected cells. These results suggest that T-cell memorymore » specific to Epstein-Barr virus keeps the virus under control and that the precursor frequency assay is useful for the evaluation of immune responses to Epstein-Barr virus. However, no significant effect of atomic bomb radiation on the precursor frequency was observed in the present study, probably due to the limited number of participants. 24 refs., 4 figs., 2 tabs.« less

Adiabatic perturbation theory for atoms and molecules in the low-frequency regime

NASA Astrophysics Data System (ADS)

Martiskainen, Hanna; Moiseyev, Nimrod

2017-12-01

There is an increasing interest in the photoinduced dynamics in the low frequency, ω, regime. The multiphoton absorptions by molecules in strong laser fields depend on the polarization of the laser and on the molecular structure. The unique properties of the interaction of atoms and molecules with lasers in the low-frequency regime imply new concepts and directions in strong-field light-matter interactions. Here we represent a perturbational approach for the calculations of the quasi-energy spectrum in the low-frequency regime, which avoids the construction of the Floquet operator with extremely large number of Floquet channels. The zero-order Hamiltonian in our perturbational approach is the adiabatic Hamiltonian where the atoms/molecules are exposed to a dc electric field rather than to ac-field. This is in the spirit of the first step in the Corkum three-step model. The second-order perturbation correction terms are obtained when i ℏ ω ∂/∂ τ serves as a perturbation and τ is a dimensionless variable. The second-order adiabatic perturbation scheme is found to be an excellent approach for calculating the ac-field Floquet solutions in our test case studies of a simple one-dimensional time-periodic model Hamiltonian. It is straightforward to implement the perturbation approach presented here for calculating atomic and molecular energy shifts (positions) due to the interaction with low-frequency ac-fields using high-level electronic structure methods. This is enabled since standard quantum chemistry packages allow the calculations of atomic and molecular energy shifts due to the interaction with dc-fields. In addition to the shift of the energy positions, the energy widths (inverse lifetimes) can be obtained at the same level of theory. These energy shifts are functions of the laser parameters (low frequency, intensity, and polarization).

Low-Light-Shift Cesium Fountain without Mechanical Shutters

NASA Technical Reports Server (NTRS)

Enzer, Daphna

2008-01-01

A new technique for reducing errors in a laser-cooled cesium fountain frequency standard provides for strong suppression of the light shift without need for mechanical shutters. Because mechanical shutters are typically susceptible to failure after operating times of the order of months, the elimination of mechanical shutters could contribute significantly to the reliability of frequency standards that are required to function continuously for longer time intervals. With respect to the operation of an atomic-fountain frequency standard, the term "light shift" denotes an undesired relative shift in the two energy levels of the atoms (in this case, cesium atoms) in the atomic fountain during interrogation by microwaves. The shift in energy levels translates to a frequency shift that reduces the precision and possibly accuracy of the frequency standard. For reasons too complex to describe within the space available for this article, the light shift is caused by any laser light that reaches the atoms during the microwave- interrogation period, but is strongest for near-resonance light. In the absence of any mitigating design feature, the light shift, expressed as a fraction of the standard fs frequency, could be as large as approx. 2 x 10(exp -11), the largest error in the standard. In a typical prior design, to suppress light shift, the intensity of laser light is reduced during the interrogation period by using a single-pass acoustooptic modulator to deflect the majority of light away from the main optical path. Mechanical shutters are used to block the remaining undeflected light to ensure complete attenuation. Without shutters, this remaining undeflected light could cause a light shift of as much as .10.15, which is unacceptably large in some applications. The new technique implemented here involves additionally shifting the laser wavelength off resonance by a relatively large amount (typically of the order of nanometers) during microwave interrogation. In this design, when microwave interrogation is not underway, the atoms are illuminated by a slave laser locked to the lasing frequency of a lower power master laser.

A compact micro-wave synthesizer for transportable cold-atom interferometers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lautier, J.; Lours, M.; Landragin, A., E-mail: arnaud.landragin@obspm.fr

2014-06-15

We present the realization of a compact micro-wave frequency synthesizer for an atom interferometer based on stimulated Raman transitions, applied to transportable inertial sensing. Our set-up is intended to address the hyperfine transitions of {sup 87}Rb at 6.8 GHz. The prototype is evaluated both in the time and the frequency domain by comparison with state-of-the-art frequency references developed at Laboratoire national de métrologie et d'essais−Systémes de référence temps espace (LNE-SYRTE). In free-running mode, it features a residual phase noise level of −65 dB rad{sup 2} Hz{sup −1} at 10 Hz offset frequency and a white phase noise level in themore » order of −120 dB rad{sup 2} Hz{sup −1} for Fourier frequencies above 10 kHz. The phase noise effect on the sensitivity of the atomic interferometer is evaluated for diverse values of cycling time, interrogation time, and Raman pulse duration. To our knowledge, the resulting contribution is well below the sensitivity of any demonstrated cold atom inertial sensors based on stimulated Raman transitions. The drastic improvement in terms of size, simplicity, and power consumption paves the way towards field and mobile operations.« less

The ACES mission: scientific objectives and present status

NASA Astrophysics Data System (ADS)

Cacciapuoti, L.; Dimarcq, N.; Salomon, C.

2017-11-01

"Atomic Clock Ensemble in Space" (ACES) is a mission in fundamental physics that will operate a new generation of atomic clocks in the microgravity environment of the International Space Station (ISS). The ACES clock signal will combine the medium term frequency stability of a space hydrogen maser (SHM) and the long term stability and accuracy of a frequency standard based on cold cesium atoms (PHARAO). Fractional frequency stability and accuracy of few parts in 1016 will be achieved. The on-board time base distributed on Earth via a microwave link (MWL) will be used to test fundamental laws of physics (Einstein's theories of Special and General Relativity, Standard Model Extension, string theories…) and to develop applications in time and frequency metrology, universal time scales, global positioning and navigation, geodesy and gravimetry. After a general overview on the mission concept and its scientific objectives, the present status of ACES instruments and sub-systems will be discussed.

Temporal interference with frequency-controllable long photons from independent cold atomic sources

NASA Astrophysics Data System (ADS)

Qian, Peng; Gu, Zhenjie; Wen, Rong; Zhang, Weiping; Chen, J. F.

2018-01-01

The interference of single photons from independent sources is an essential tool in quantum information processing. However, the interfering of photons with long temporal states in a time-resolved manner has rarely been studied. This is because without transmitting spectral filters or coupling to a cavity mode single photons generated in traditional nonlinear crystals suffer from a short temporal profile below 1 ns. With spectral correlation maintained in the biphotons generated from spontaneous four-wave mixing process in cold atom clouds, here we demonstrate the temporal interference of two frequency-tunable long photons from two independent cold atomic sources. We observe and analyze the interference of frequency-mismatched photons, where the phenomenon of the quantum beat at megahertz separation is displayed. Our paper provides more details for the quantum beat of two independent narrow-band single photons, which may find potential application in frequency-encoded photonic qubits in quantum information processing.

High-precision two-dimensional atom localization from four-wave mixing in a double-Λ four-level atomic system

NASA Astrophysics Data System (ADS)

Shui, Tao; Yang, Wen-Xing; Chen, Ai-Xi; Liu, Shaopeng; Li, Ling; Zhu, Zhonghu

2018-03-01

We propose a scheme for high-precision two-dimensional (2D) atom localization via the four-wave mixing (FWM) in a four-level double-Λ atomic system. Due to the position-dependent atom-field interaction, the 2D position information of the atoms can be directly determined by the measurement of the normalized light intensity of output FWM-generated field. We further show that, when the position-dependent generated FWM field has become sufficiently intense, efficient back-coupling to the FWM generating state becomes important. This back-coupling pathway leads to competitive multiphoton destructive interference of the FWM generating state by three supplied and one internally generated fields. We find that the precision of 2D atom localization can be improved significantly by the multiphoton destructive interference and depends sensitively on the frequency detunings and the pump field intensity. Interestingly enough, we show that adjusting the frequency detunings and the pump field intensity can modify significantly the FWM efficiency, and consequently lead to a redistribution of the atoms. As a result, the atom can be localized in one of four quadrants with holding the precision of atom localization.