119 research outputs found
Fluorescence polarization imaging of Sisyphus cooling in an atomic beam
No full textSisyphus cooling plays an important role in many cold atom applications including the formation of Bose-Einstein condensates and collimation of atomic beams. Here we present a method for measuring the localization of atoms by monitoring the polarization of fluorescence, providing a quantitative two-dimensional image of the cooling process. We outline the concept and provide theoretical models for the optical pumping, cooling, and channeling mechanisms, and present experimental data revealing the development of strong fluorescence polarization in an atomic beam during transverse (lin⊥lin) cooling.B. M. Sparkes, K. P. Weber, C. J. Hawthorn, M. R. Walkiewicz, E. J. D. Vredenbregt and R. E. Scholte
Ultracold plasmas : phenomena and applications
No full textUltracold plasmas (UCPs) represent a marriage between the seemingly distinct fields of cold atom physics and plasma physics. In cold atom physics, dilute clouds of atoms can be trapped with laser radiation and cooled to J.1Ktemperatures. In contrast, in plasma physics the constituents generally have temperatures in the 1,000K-1O,000K range as well as much higher density. In 1999,Rolston and co-workers [1] first converted a cloud of laser-cooled atoms into a plasma by photo-ionizing the atoms just above threshold. This provides very unusual circumstances:the temperature of ions and neutrals is O.OOIK,that of electrons 10K! Such ultra-cold plasmas therefore are interesting subjects for fundamentalplasma physics studies.
In a recent paper [2], we argued that ultracold plasmas (UCPs) may in addition provide an entirely new way of generatinghigh-brightnesscharged-particlebeams, such as used in focused-ion beams, laser synchrotrons, and ultra-fast electron microscopy.
Here, a low temperature T is beneficial for the intrinsic (transverse) brightness B of a
source since B = II(A1), where I is the current and A the cross-sectional area. I will discuss an experimental investigation of the properties of ion and electron beams extracted from ultracold plasmas, which shows that such beams indeed have low temperatures, and, as a result, high angular intensity
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