Berlin 2005 – scientific programme

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A: Atomphysik

A 15: Cold Atoms; Ultra-cold Atoms; and Atoms in Traps; BEC; I

A 15.2: Fachvortrag

Tuesday, March 8, 2005, 17:00–17:15, HU 3094

Spectroscopy of ultracold interacting Rydberg atoms — •Marcel Mudrich, Nassim Zahzam, Thibault Vogt, Daniel Comparat, and Pierre Pillet — Laboratoire Aimé Cotton, 91405 Orsay, France

Rydberg atoms have regained great interest in the past years in particular since strong dipole-dipole forces make them a candidate system for realizing quantum information schemes. The first step in this direction has recently been undertaken by observing the suppression of excitation due to dipole-dipole interaction between Rydberg atoms ("dipole blockade"), which goes along with spectral broadening [1,2]. We present high resolution spectroscopic measurements in an ultracold gas of cesium Rydberg atoms. We compare a combined pulsed and cw excitation scheme with a scheme in which Rydberg atoms are excited by a pulsed laser and depumped into a short-lived state using a cw laser. We observe strong spectral broadening due to the inhomogeneous Stark-shift induced by photo-ions. This broadening can be suppressed in the cw excitation scheme by strong coupling which leads to "hole burning", or in the depumping scheme by time-delayed depumping to let the ions move away from the Rydberg atoms. Thus we are able to spectrally resolve the resonant dipole-dipole interaction between ultracold Rydberg atoms.
D. Tong et al., Phys. Rev. Lett. 93 063001 (2004)
K. Singer et al., Phys. Rev. Lett. 93 163001 (2004)