We investigate a solid-state, reversible, alkali-ion battery (AIB) capable of regulating the density of alkali atoms in a vacuum system used for the production of laser-cooled atoms. The cold-atom sample can be used with in-vacuum chronoamperometry as a diagnostic for the voltage-controlled electrochemical reaction that sources or sinks alkali atoms into the vapor. In a combined reaction-diffusion-limited regime, we show that the number of laser-cooled atoms in a magneto-optical trap can be increased both by initially loading the AIB from the vapor for longer, and by using higher voltages across the AIB when atoms are subsequently sourced back into the vapor. The time constants associated with the change in atom number in response to a change in AIB voltage are in the range of 0.5 s - 40 s. The AIB alkali reservoir is demonstrated to survive oxidization during atmospheric exposure, simplifying reservoir loading prior to vacuum implementation as a replacement for traditional resistively-heated dispensers. The AIB capabilities may provide an improved atom number stability in next-generation atomic clocks and sensors, while also facilitating fast loading and increased interrogation times.
We realize simultaneous quantum degeneracy in mixtures consisting of the alkali and alkalineearth-like atoms Li and Yb. This is accomplished within an optical trap by sympathetic cooling of the fermionic isotope 6Li with evaporatively cooled bosonic 174Yb and, separately, fermionic 173Yb.Using cross-thermalization studies, we also measure the elastic s-wave scattering lengths of both Li-Yb combinations, |a6Li-174Yb| = 1.0\pm0.2 nm and |a6Li-173Yb| = 0.9\pm0.2 nm. The equality of these lengths is found to be consistent with mass-scaling analysis. The quantum degenerate mixtures of Li and Yb, as…
A glass ultrahigh vacuum chamber with rubidium alkali metal dispensers and non-evaporable getter pumps has been developed and used to create a cold atomic sample in a chamber that operates with only passive vacuum pumps. The ion-mass spectrum of evaporated gases from the alkali metal dispenser has been recorded as a function of dispenser current. The efficacy of the non-evaporable getter pumps in promoting and maintaining vacuum has been characterized by observation of the Rb vapor optical absorption on the D2 transition at 780 nm and vacuum chamber pressure rate of rise tests. We have demonst…
We report the operation of a dual Rb/Cs atomic fountain clock. 133Cs and 87Rb atoms are cooled, launched, and detected simultaneously in LNE-SYRTE's FO2 double fountain. The dual clock operation occurs with no degradation of either the stability or the accuracy. We describe the key features for achieving such a simultaneous operation. We also report on the results of the first Rb/Cs frequency measurement campaign performed with FO2 in this dual atom clock configuration, including a new determination of the absolute 87Rb hyperfine frequency.
Atomic clocks based on an Al$^+$ ion sympathetically cooled by a laser-cooled alkaline-earth ion have achieved unprecedented accuracy. Here, we investigate theoretically interactions and charge transfer dynamics of an Al$^+$ ion immersed in an ultracold gas of Rb and Sr atoms. We calculate potential energy curves and transition electric dipole moments for the (Al+Rb)$^+$ and (Al+Sr)$^+$ ion-atom systems using coupled cluster and multireference configuration interaction methods with scalar relativistic effects included within the small-core energy-consistent pseudopotentials in Rb and Sr atoms.…
We calculate the light-induced collisional loss of laser-cooled and trapped magnesium atoms for detunings up to 50 atomic linewidths to the red of the ^1S_0-^1P_1 cooling transition. We evaluate loss rate coefficients due to both radiative and nonradiative state-changing mechanisms for temperatures at and below the Doppler cooling temperature. We solve the Schrodinger equation with a complex potential to represent spontaneous decay, but also give analytic models for various limits. Vibrational structure due to molecular photoassociation is present in the trap loss spectrum. Relatively broad st…
Hypermetallic alkaline earth (M) oxides of formula MOM have been studied under plasma conditions that preclude insight into their formation mechanism. We present here the application of emerging techniques in ultracold physics to the synthesis of a mixed hypermetallic oxide, BaOCa$^+$. These methods, augmented by high-level electronic structure calculations, permit detailed investigation of the bonding and structure, as well as the mechanism of its formation via the barrierless reaction of Ca $(^3P_J)$ with BaOCH$_{3}^+$. Further investigations of the reaction kinetics as a function of collisi…
We measured by laser spectroscopy the isotope shifts between naturally-occurring even-isotopes of strontium ions for both the $5s\,\,^2S_{1/2}\to 5p\,\,^2P_{1/2}$ (violet) and the $4d\,\,^2D_{3/2}\to 5p\,\,^2P_{1/2}$ (infrared) dipole-allowed optical transitions. Fluorescence spectra were taken by simultaneous measurements on a two-component Coulomb crystal in a linear Paul trap containing $10^3$--$10^4$ laser-cooled Sr$^+$ ions. The isotope shifts are extracted from the experimental spectra by fitting the data with the analytical solution of the optical Bloch equations describing a three-leve…
Recent proposals suggest that lasers based on narrow dipole-forbidden transitions in cold alkaline earth atoms could achieve linewidths that are orders of magnitude smaller than linewidths of any existing lasers. Here, we demonstrate a laser based on the 7.5 kHz linewidth dipole forbidden $^3 $P$_1$ to $^1 $S$_0$ transition in laser-cooled and tightly confined $^{88}$Sr. We can operate this laser in the bad-cavity regime, where coherence is primarily stored in the atoms, or continuously tune to the more conventional good-cavity regime, where coherence is primarily stored in the light field. We…
We derive and apply an optical Bloch equation (OBE) model for describing collisions of ground and excited laser cooled alkali atoms in the presence of near-resonant light. Typically these collisions lead to loss of atoms from traps. We compare the results obtained with a quantum mechanical complex potential treatment, semiclassical Landau-Zener models with decay, and a quantum time-dependent Monte-Carlo wave packet (MCWP) calculation. We formulate the OBE method in both adiabatic and diabatic representations. We calculate the laser intensity dependence of collision probabilities and find that …
We demonstrate sub-Doppler laser cooling of $ ^{39} $K using degenerate Raman sideband cooling via the 4S$_{1/2} \rightarrow $5P$ _{1/2} $ transition at 404.8 nm. By using an optical lattice in combination with a magnetic field and optical pumping beams, we obtain a spin-polarized sample of up to $5.6 \times 10^{7}$ atoms cooled down to a sub-Doppler temperature of 4 $μ$K, reaching a peak density of $3.9 \times 10^{9}$ atoms/cm$ ^{3} $, a phase-space density greater than $ 10^{-5} $, and an average vibrational level of $ \langle ν\rangle=0.6 $ in the lattice. This work opens up the possibility…
Ultracold dysprosium gases, with a magnetic moment ten times that of alkali atoms and equal only to terbium as the most magnetic atom, are expected to exhibit a multitude of fascinating collisional dynamics and quantum dipolar phases, including quantum liquid crystal physics. We report the first laser cooling and trapping of half a billion Dy atoms using a repumper-free magneto-optical trap (MOT) and continuously loaded magnetic confinement, and we characterize the trap recycling dynamics for bosonic and fermionic isotopes. The first inelastic collision measurements in the few partial wave, 10…
An analytical model of a single-atom electron source is presented, where electrons are created by near-threshold photoionization of an isolated atom. The model considers the classical dynamics of the electron just after the photon absorption, i.e. its motion in the potential of a singly charged ion and a uniform electric field used for acceleration. From closed expressions for the asymptotic transverse electron velocities and trajectories, the effective source temperature and the effective source size can be calculated. The influence of the acceleration field strength and the ionization laser …
Laser cooling of atoms usually necessitates several laser frequencies. Alkaline atoms, for example, are cooled by two lasers with a frequency difference in the Gigahertz range. This gap cannot be closed with simple shifting techniques. Here, we present a method of generating sidebands at 6.6 GHz by modulating the current of a tapered amplifier which is seeded by an unmodulated master laser. The sidebands enable trapping of 1.1*10^9 Rubidium 87 atoms in a chip-based magneto-optical trap. Compared to the direct modulation of the master laser, this method allows for an easy implementation, a fast…
We propose the application of laser cooling to a number of transition-metal atoms, allowing numerous bosonic and fermionic atomic gases to be cooled to ultra-low temperatures. The non-zero electron orbital angular momentum of these atoms implies that strongly atom-state-dependent light-atom interactions occur even for light that is far-detuned from atomic transitions. At the same time, many transition-metal atoms have small magnetic dipole moments in their low-energy states, reducing the rate of dipolar-relaxation collisions. Altogether, these features provide compelling opportunities for futu…
Molecular ions formed in cold hybrid ion-atom experiments may find interesting applications ranging from precision measurements to controlled chemical reactions. Here, we investigate electronic structure of the Sr$_2^+$ molecular ion, which may be produced by photoassociation of laser-cooled Sr$^+$ ions immersed into an ultracold gas of Sr atoms or by ionization of ultracold Sr$_2$ molecules. Using \textit{ab initio} electronic structure methods, such as the coupled cluster and configuration interaction ones with small-core relativistic energy-consistent pseudopotentials and large Gaussian bas…
Atomic clocks play a crucial role in timekeeping, communications, and navigation systems. Recent efforts enabled by heterogeneous MEMS integration have led to the commercial introduction of Chip-Scale Atomic Clocks (CSAC) with a volume of 16 cm3, power consumption of 120 mW, and instability (Allan Deviation) of σ(τ = 1 sec) < 2e-10. In order to reduce the temperature sensitivity of next-generation CSACs for timing applications, the interaction of atoms with the environment must be minimized, which can be accomplished in an architecture based on trapped, laser-cooled atoms. In this paper, we pr…
National Institute of Standards and Technology（美国国家标准与技术研究院）；British Columbia Institute of Technology（不列颠哥伦比亚理工学院）；University of Bremen（不来梅大学）；Physikalisch-Technische Bundesanstalt（德国联邦物理技术研究院）；University of Maryland（马里兰大学）；University of British Columbia（不列颠哥伦比亚大学）
