Measurement of temperature of laser cooled atoms by one-dimensional expansion in a magneto-optical trap

Pradhan, Swarupananda; Jagatap, B. N.

doi:10.1063/1.2827517

Cited by 14 publications

(10 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The Rb atoms were captured from background vapour released by a getter source [30]. The number densities (typically n = 1 × 10 9 cm −3 ) and temperatures of the ultracold atoms in the MOT (T = 150 − 200 µK) were determined using standard fluorescence-measurement and time-of-flight methods, respectively [31][32][33]. In our experiments, the MOT-and ion-cooling laser beams were alternately blocked by a mechanical chopper operating at 1000 Hz to prevent photoionization of Rb in the (4p) 2 P 3/2 state by the 397 nm laser [4].…”

Section: A the Ion-atom Hybrid Trapmentioning

confidence: 99%

Ion-neutral chemistry at ultralow energies: dynamics of reactive collisions between laser-cooled Ca⁺ ions and Rb atoms in an ion-atom hybrid trap

et al. 2013

View full text Add to dashboard Cite

Cold chemical reactions between laser-cooled Ca+ ions and Rb atoms were studied in an ion-atom hybrid trap. Reaction rate constants were determined in the range of collision energies E coll /kB = 20 mK-20 K. The lowest energies were achieved in experiments using single localized Ca + ions. Product branching ratios were studied using resonant-excitation mass spectrometry. The dynamics of the reactive processes in this system (non-radiative and radiative charge transfer as well as radiative association leading to the formation of CaRb + molecular ions) have been analyzed using high-level quantum-chemical calculations of the potential energy curves of CaRb + and quantumscattering calculations for the radiative channels. For the present low-energy scattering experiments, it is shown that the energy dependence of the reaction rate constants is governed by long-range interactions in line with the classical Langevin model, but their magnitude is determined by shortrange non-adiabatic and radiative couplings which only weakly depend on the asymptotic energy. The quantum character of the collisions is predicted to manifest itself in the occurrence of narrow shape resonances at well-defined collision energies. The present results highlight both universal and system-specific phenomena in cold ion-neutral reactive collisions.

show abstract

Section: A the Ion-atom Hybrid Trapmentioning

confidence: 99%

Ion-neutral chemistry at ultralow energies: dynamics of reactive collisions between laser-cooled Ca⁺ ions and Rb atoms in an ion-atom hybrid trap

et al. 2013

View full text Add to dashboard Cite

show abstract

“…The magnetic field can be completely turned on or off within 0.2ms according to our measurement. We use release and recapture method [18] to measure the cold atomic temperature after PGC process, which has been described in Fig.1. The temperature of cold atoms can be obtained from the expansion process by fitting this equation…”

Section: Experimental Setup and Timing Sequencementioning

confidence: 99%

Systematically investigating the polarization gradient cooling in an optical molasses of ultracold cesium atoms

Ji¹,

Yuan²,

Zhao³

et al. 2014

Chinese Phys. B

View full text Add to dashboard Cite

We systematically investigate the dependence of the temperature of cold cesium atoms of polarization gradient cooling (PGC) in optical molasses on experimental parameters, which contain changing modes of cooling laser, PGC interaction time, cooling laser frequency and its intensity. The ′SR′ mode of cooling laser, that means the cooling laser frequency is changed with step mode and cooling laser intensity is changed with ramp mode, is found to be the best for PGC comparing with other ′SS′, ′RS′, and ′RR′ modes. We introduce a statistical explanation and an exponential decay function to explain the variation of cold atomic temperature on time. The heating effect is observed when the cooling laser intensity is lower than the saturation intensity of cold atoms. After optimization, the lowest temperature of cold cesium atoms is observed to be about 4µK with the number of 2×10 9 , the density of 1×10 11 /cm 3 and the phase space density of 4.4×10 -5 . The optimization process and analysis of controllable experimental parameters are also meaningful for other cold atomic systems.

show abstract

“…1 (b)). The number density and temperature of the Rb atoms in the MOT were established using standard fluorescence measurement and time-of-flight methods, respectively [20]. The fluorescence of either the ions or the neutral atoms was isolated using narrow-bandpass color filters and imaged onto a CCD camera (Figure 1 (c)).…”

mentioning

confidence: 99%

Light-Assisted Ion-Neutral Reactive Processes in the Cold Regime: Radiative Molecule Formation versus Charge Exchange

et al. 2011

View full text Add to dashboard Cite

We present a combined experimental and theoretical study of cold reactive collisions between lasercooled Ca + ions and Rb atoms in an ion-atom hybrid trap. We observe rich chemical dynamics which are interpreted in terms of non-adiabatic and radiative charge exchange as well as radiative molecule formation using high-level electronic structure calculations. We study the role of light-assisted processes and show that the efficiency of the dominant chemical pathways is considerably enhanced in excited reaction channels. Our results illustrate the importance of radiative and non-radiative processes for the cold chemistry occurring in ion-atom hybrid traps.Over the past few years, impressive progress has been achieved in the study of reactive collisions at ultralow energies. Recent landmark studies using neutral molecules highlighted the distinct quantum character of reactive processes in this regime and demonstrated new approaches for an unprecedented control of molecular collisions [3,4]. Ion-neutral reactions are another class of processes which exhibit different long-range interactions and therefore a different chemical behavior in comparison to neutrals [5][6][7][8][9][10][11]. With the development of hybrid traps in which laser-cooled atomic ions stored in a radiofrequency ion trap are combined with ultracold neutral atoms in a magneto-optical trap [12][13][14] or a BoseEinstein-condensate [15,16], the study of ion-neutral reactions in the energy range between 1 and 10 −3 Kelvin (usually termed the "cold" regime) has recently become possible. Under these conditions, only a few partial waves contribute to the collision so that resonance as well as radiative effects can become important [5,6,10,17].One key question pertains to the types of chemical processes which can occur in hybrid traps. So far, either fast near-resonant homonuclear charge exchange (in Yb-Yb . For Rb-Yb + , the latter observation was rationalized in terms of radiative and non-radiative charge exchange [18]. The feasibility of molecular-ion formation has also been considered, and evidence for a radiative mechanism has recently been found in the Ca-Yb + system [14]. However, a general understanding of the interplay between these reactive processes and in particular the role of light remains to be established.In the current study, we present a combined experimental and theoretical study of ion-neutral reactive collisions in a Rb-Ca + hybrid trap. Our experimental results are interpreted using high-level electronic structure calculations of the CaRb + potential energy curves (PECs) up to the twenty-second dissociation limit. We observe rich chemical dynamics which we rationalize in terms of nonadiabatic and radiative effects. We show that the efficiency of the dominant chemical processes (radiative molecule formation, radiative and non-radiative charge exchange) is considerably enhanced in excited reaction channels populated in the presence of radiation. Using Rb-Ca + as a model system, our results illustrate the reactive processes which can occu...

show abstract

Measurement of temperature of laser cooled atoms by one-dimensional expansion in a magneto-optical trap

Cited by 14 publications

References 15 publications

Ion-neutral chemistry at ultralow energies: dynamics of reactive collisions between laser-cooled Ca⁺ ions and Rb atoms in an ion-atom hybrid trap

Ion-neutral chemistry at ultralow energies: dynamics of reactive collisions between laser-cooled Ca⁺ ions and Rb atoms in an ion-atom hybrid trap

Systematically investigating the polarization gradient cooling in an optical molasses of ultracold cesium atoms

Light-Assisted Ion-Neutral Reactive Processes in the Cold Regime: Radiative Molecule Formation versus Charge Exchange

Contact Info

Product

Resources

About

Measurement of temperature of laser cooled atoms by one-dimensional expansion in a magneto-optical trap

Cited by 14 publications

References 15 publications

Ion-neutral chemistry at ultralow energies: dynamics of reactive collisions between laser-cooled Ca+ ions and Rb atoms in an ion-atom hybrid trap

Ion-neutral chemistry at ultralow energies: dynamics of reactive collisions between laser-cooled Ca+ ions and Rb atoms in an ion-atom hybrid trap

Systematically investigating the polarization gradient cooling in an optical molasses of ultracold cesium atoms

Light-Assisted Ion-Neutral Reactive Processes in the Cold Regime: Radiative Molecule Formation versus Charge Exchange

Contact Info

Product

Resources

About

Ion-neutral chemistry at ultralow energies: dynamics of reactive collisions between laser-cooled Ca⁺ ions and Rb atoms in an ion-atom hybrid trap

Ion-neutral chemistry at ultralow energies: dynamics of reactive collisions between laser-cooled Ca⁺ ions and Rb atoms in an ion-atom hybrid trap