Réalisation d'un réseau de pièges annulaires : une première étape vers une porte logique quantique avec des atomes froids

Characterization and modelling of the hollow beam produced by a real conical lens

“…This enables the use of such beams in interferometric experiments, as e.g. in the realization of optical lattices [15]. In most of the applications, the present system will win in convenience if a second conical lens, located just after the Bessel zone of the first one, is added to the convergent conical lens doublet.…”

Rotational bosonic current in a quasi-condensate confined in an optical toroidal trap

“…In the radial direction, the ring radius is approximately the radius of the laser beam. Extending the experimental parameters of [18] to Rb atoms, with a beam radius of about 50 µm, potential height of 10 E R and ω R ∼ 2π × 3.7 kHz, where E R and ω R are respectively the recoil energy and frequency, one can find ω r ∼ 2π × 0.06 kHz, ω z ∼ 2π × 15 kHz and ∼ 2π × 0.023 Hz (for the p = 0 → p = 1 transition).…”

“…Moreover, at sufficiently low temperatures with the radial motion of particles (the centre of mass modes along the x and y directions) essentially frozen because the radial frequency ω r is much more than the mean-field interaction energy, a tight confinement regime is reached. The experimental configuration of [18,19] is so flexible that it can satisfy these conditions very easily, as in section 2. In that regime, some degrees of freedom are eliminated and the radial motion of particles (the centre of mass modes along the x and y directions) is essentially frozen.…”

“…In this regime, the system forms a quasi-condensate, with local phase coherence, rather than the global coherence 1). This optical torus can be generated by the interference of a standard Gaussian beam with a counter-propagating hollow beam generated by a pair of axicon [18,19]. associated with a true condensate.…”

“…It has been experimentally demonstrated that a blue-detuned hollow Bessel laser beam formed by an axicon can be successfully used to trap laser cooled metastable xenon atoms [17]. Experimentally, caesium atoms have been trapped in an all blue-detuned stack of optical rings by the interference of a standard Gaussian beam with a counter-propagating hollow beam generated by a pair of axicon [18,19]. We propose the use of such an experimental scheme with a TEM 01 beam in order to realize the 2D optical rotator.…”