Abstract There are an increasing number of experimental scenarios where near-resonant light is applied to atoms tightly trapped in far off-resonant optical fields, such as for quantum optics ...applications or for atom imaging. Oftentimes, the electronic ground and excited states involved in the optical transition experience unequal trapping potentials. Here, we systematically analyze the effects of unequal trapping on near-resonant atom–light interactions. In particular, we identify regimes where such trapping can lead to significant excess heating compared to atoms in state-independent potentials, and a reduction of total and elastic scattering cross sections associated with a decreased atom–photon interaction efficiency. Understanding these effects can be valuable for achieving maximum efficiency in quantum optics experiments or atom imaging setups, where efficient atom–light interactions on resonance are desired, but achieving equal trapping is not feasible.
Abstract
We investigate time-domain optics for atomic quantum matter. Within a matter-wave analog of the thin-lens formalism, we study optical lenses of different shapes and refractive powers to ...precisely control the dispersion of Bose–Einstein condensates. Anharmonicities of the lensing potential are incorporated in the formalism with a decomposition of the center-of-mass motion and expansion of the atoms, allowing to probe the lensing potential with micrometer resolution. By arranging two lenses in time formed by the potentials of an optical dipole trap and an atom-chip trap, we realize a magneto-optical matter-wave telescope. We employ this hybrid telescope to manipulate the expansion and aspect ratio of the ensembles. The experimental results are compared to numerical simulations that involve Gaussian shaped potentials to accommodate lens shapes beyond the harmonic approximation.
We consider the cold bosonic ensemble trapped by a helical interference pattern in the optical loop scheme. This rotating helical potential is produced by the two slightly detuned counter-propagating ...Laguerre–Gaussian laser beams with counter-directed orbital angular momenta ±ℓℏ. The detuning δω may occur due to rotational Doppler effect. The superfluid hydrodynamics is analyzed for the large number of trapped atoms in Thomas–Fermi approximation. For the highly elongated trap the Gross–Pitaevskii equation is solved in a slowly varying envelope approximation. The speed of axial translation and angular momenta of interacting atomic cloud are evaluated. In the T→0 limit the angular momentum of the helical cloud is expected to be zero while toroidal trapping geometry leads to 2ℓℏ angular momentum per trapped atom.
► Counter propagating detuned Laguerre–Gaussian laser beams. ► Superfluid motion in rotating helical trap. ► Orbital angular momentum of rotating atomic cloud.
Application of Maslov’s asymptotic methods to equations that arise in the theory of optical lattices was considered. The occurrence of a small parameter in the Schrödinger equations with potentials ...of three-dimensional and controlled optical lattice was investigated and the conditions of application of Maslov’s asymptotic methods for solving these equations was determined. Consideration of different conditions imposed on the parameters in these potentials led to the use of two different methods for solving the arising equations: Maslov’s method of a complex germ and Maslov’s operator-valued method of a complex germ. Expressions that can be used to calculate the desired characteristics of the atomic systems under consideration in optical lattices were derived.
We describe the realization of Bose—Einstein condensates (BEC) of ⁸⁷Rb atoms with relatively large number of atoms at high density, in laser-optical traps in our laboratory. Ştarting from a giant ...magneto-optical trap containing nearly 10¹⁰ atoms, we transfer about 5 x 10⁷ atoms into the optical dipole trap formed by crossing two high-power focused CO₂ laser beams. BEC containing about 10⁵ atoms was produced by forced evaporative cooling of the atomic sample in the crossed optical trap down to about 140 nK, in just about a second. The BEC was also produced in a 1D optical lattice formed by the standing wave of a retro-reflected focused CO₂ laser beam, with about 80,000 atoms in the condensate. Effects of mean-field interaction characteristic of BEC were observed in the expansion dynamics of the condensate. We discuss both the techniques and the innovations that enabled the efficient execution of the multiple steps involved in producing the BEC, starting from a thermal sample of rubidium gas.
Thermally stimulated luminescence (TSL) study of high purity carbazole crystals revealed the presence of the shallow traps for charge-carriers, which were interpreted in terms of dipole traps. A ...model that attributes these dipole traps to the orientational defects formed by a molecule of the crystal rotated by 180° along the long in-plane axis compared to the neighbor molecules has been suggested. Charge-carrier traps arise due to electrostatic interaction of the carrier with the permanent dipole moment of reoriented molecule. The depths of trapping states established on the molecules of the crystal neighboring one, two and three reoriented molecules have been calculated. The results of the calculations are in good agreement with the depths of the dipole traps obtained by fractional TSL technique.
Charge Carrier Dipole Traps in Neat Molecular Crystals of Polar Molecules Skryshevski, Yu; Ostapenko, N.; Kadashchuk, A. ...
Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals,
12/1/1998, Letnik:
324, Številka:
1
Journal Article, Conference Proceeding
The charge-carrier traps in the neat carbazole crystal have been found and were interpreted as dipole traps formed by the intrinsic orientational crystalline defects appearing when a molecule is ...rotated by 180° along the long in-plane axis as compared to the bulk molecules. The depths of trapping states established on the neighboring molecules of crystal in the vicinity of one, two and tree reoriented molecules was calculated. Energetic spectrum of dipole traps was studied by fractional thermoluminescence and the experimental results are in good agreement with calculation.
We demonstrate the trapping and manipulation of single neutral atoms in reconfigurable arrays of optical tweezers. Our approach offers unparalleled speed by using a Texas instruments digital ...micro-mirror device as a holographic amplitude modulator with a frame rate of 20 000 per second. We show the trapping of static arrays of up to 20 atoms, as well as transport of individually selected atoms over a distance of 25 m with laser cooling and 4 m without. We discuss the limitations of the technique and the scope for technical improvements.
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