Rydberg excitation of a Bose-Einstein condensate

We have performed two-photon excitation via the 6P3/2 state to n=50-80 S or D Rydberg state in Bose-Einstein condensates of rubidium atoms. The Rydberg excitation was performed in a quartz cell, where electric fields generated by plates external to the cell created electric charges on the cell walls. Avoiding accumulation of the charges and realizing good control over the applied electric field was obtained when the fields were applied only for a short time, typically a few microseconds. Rydberg excitations of the Bose-Einstein condensates loaded into quasi one-dimensional traps and in optical lattices have been investigated. The results for condensates expanded to different sizes in the one-dimensional trap agree well with the intuitive picture of a chain of Rydberg excitations controlled by the dipole-dipole interaction. The optical lattice applied along the one-dimensional geometry produces localized, collective Rydberg excitations controlled by the nearest-neighbour blockade.Comment: 7 pages, 7 figures, Laser Physics in press. arXiv admin note: text overlap with arXiv:1103.423

Rubidium Rydberg macrodimers

We explore long-range interactions between two atoms excited into high principal quantum number n Rydberg states, and present calculated potential energy surfaces (PES) for various symmetries of doubly excited ns and np rubidium atoms. We show that the PES for these symmetries exhibit deep (~GHz) potential wells, which can support very extended (~micrometers) bound vibrational states (macrodimers). We present n-scaling relations for both the depth De of the wells and the equilibrium separations Re of these macrodimers, and explore their response to small electric fields and stability with respect to predissociation. Finally, we present a scheme to form and study these macrodimers via photoassociation, and show how one can probe the various \ell-character of the potential wells

Ion detection in the photoionization of a Rb Bose-Einstein condensate

Two-photon ionization of Rubidium atoms in a magneto-optical trap and a Bose-Einstein condensate (BEC) is experimentally investigated. Using 100 ns laser pulses, we detect single ions photoionized from the condenstate with a 35(10)% efficiency. The measurements are performed using a quartz cell with external electrodes, allowing large optical access for BECs and optical lattices.Comment: 14 pages, 7 figure

Rydberg spectroscopy of a Rb MOT in the presence of applied or ion created electric fields

Rydberg spectroscopy of rubidium cold atoms trapped in a magneto-optical trap (MOT) was performed in a quartz cell. When electric fields acting on the atoms generated by a plate external to the cell were continuously applied, electric charges on the cell walls were created, as monitored on the Rydberg spectra. Avoiding accumulation of the charges and realizing good control over the applied electric field was instead obtained when the fields were applied only for a short time, typically a few microseconds. In a two-photon excitation via the 6(2)P state to the Rydberg state, the laser resonant with the 5(2)S-6(2)P transition photoionizes the excited state. The photoionization-created ions produce an internal electric field which deforms the excitation spectra, as monitored on the Autler-Townes absorption spectra. (C) 2010 Optical Society of America RI Ciampini, Donatella/E-2097-201

Rydberg excitations in Bose-Einstein condensates in quasi-one-dimensional potentials and optical lattices

We experimentally realize Rydberg excitations in Bose-Einstein condensates of rubidium atoms loaded into quasi-one-dimensional traps and in optical lattices. Our results for condensates expanded to different sizes in the one-dimensional trap agree well with the intuitive picture of a chain of Rydberg excitations. We also find that the Rydberg excitations in the optical lattice do not destroy the phase coherence of the condensate, and our results in that system agree with the picture of localized collective Rydberg excitations including nearest-neighbor blockade

Rydberg spectroscopy of a Rb MOT in the presence of applied or ion created electric fields

Rydberg spectroscopy of rubidium cold atoms trapped in a magneto-optical trap (MOT) was performed in a quartz cell. When electric fields acting on the atoms generated by a plate external to the cell were continuously applied, electric charges on the cell walls were created, as monitored on the Rydberg spectra. Avoiding accumulation of the charges and realizing good control over the applied electric field was instead obtained when the fields were applied only for a short time, typically a few microseconds. In a two-photon excitation via the 6(2)P state to the Rydberg state, the laser resonant with the 5(2)S-6(2)P transition photoionizes the excited state. The photoionization-created ions produce an internal electric field which deforms the excitation spectra, as monitored on the Autler-Townes absorption spectra

Rydberg excitation in one dimensional system and optical lattices

Highly excited atoms exhibit large long range dipole-dipole interaction, making them a perfect tool for studying strongly correlated quantum gases and for implementing basic elements for quantum computation with cold neutral atoms [1,2]. Here we present an experimental study of Rydberg excitations of rubidium Bose Einstein condensates loaded in a quasi-one dimensional potential (dipole trap) and in periodic potentials (optical lattices). The excitation of Rydberg atoms in periodic potentials is one of the possible paths towards reaching the scalability requirements in quantum computation devices, with quantum gates based on the dipole blockade effect [3,4]