7 research outputs found
Magneto-optical trapping of bosonic and fermionic neon isotopes and their mixtures: isotope shift of the ^3P_2 to ^3D_3 transition and hyperfine constants of the ^3D_3 state of Ne-21
We have magneto-optically trapped all three stable neon isotopes, including
the rare Ne-21, and all two-isotope combinations. The atoms are prepared in the
metastable ^3P_2 state and manipulated via laser interaction on the ^3P_2 to
^3D_3} transition at 640.2nm. These cold (T = 1mK) and environmentally
decoupled atom samples present ideal objects for precision measurements and the
investigation of interactions between cold and ultracold metastable atoms. In
this work, we present accurate measurements of the isotope shift of the ^3P_2
to ^3D_3 transition and the hyperfine interaction constants of the ^3D_3 state
of Ne-21. The determined isotope shifts are (1625.9\pm0.15)MHz for Ne-20 to
Ne-22, (855.7\pm1.0)MHz for Ne-20 to Ne-21, and (770.3\pm1.0)MHz for Ne-21 to
Ne-22. The obtained magnetic dipole and electric quadrupole hyperfine
interaction constants are A(^3D_3)= (-142.4\pm0.2)MHz and
B(^3D_3)=(-107.7\pm1.1)MHz, respectively. All measurements give a reduction of
uncertainty by about one order of magnitude over previous measurements
Trapping fermionic and bosonic helium atoms
This thesis presents experimental and theoretical work performed at the Laser Centre of the Vrije Universiteit in Amsterdam to study laser-cooled metastable triplet helium atoms. Samples containing about 3x10^8 helium atoms-either fermionic helium-3 atoms, bosonic helium-4 atoms or mixtures thereof-are cooled to a temperature around 1 mK and form the starting point of the presented studies. The studies include an investigation of cold ionizing collisions in the absence of resonant light, an investigation of magneto-optical trapping with ultraviolet light, a feasibility study of an atomic fountain clock based on metastable helium-3 atoms and the first demonstration of magneto-optical trapping of an isotopic mixture of metastable helium atoms.Hogervorst, W. [Promotor]Vassen, W. [Copromotor
Simultaneous magneto-optical trapping of a boson-fermion mixture of metastable helium atoms
The fermionic metastabl
Homonuclear ionizing collisions of laser-cooled metastable helium atoms
We present a theoretical and experimental investigation of homonuclear
ionizing collisions of laser-cooled metastable helium atoms, considering both
the fermionic He-3 and bosonic He-4 isotope. The theoretical description
combines quantum threshold behavior, Wigner's spin-conservation rule and
quantum statistical symmetry requirements in a single-channel model,
complementing a more complete close-coupling theory that has been reported for
collisions of metastable He-4 atoms. The model is supported with measurements
(in the absence of light fields) of ionization rates in magneto-optically
trapped samples, that contain about 3*10^8 atoms of a single isotope. The
ionization rates are determined from measurements of trap loss due to
light-assisted collisions combined with comparative measurements of the ion
production rate in the absence and presence of trapping light. Theory and
experiment show good agreement.Comment: 15 pages, 6 figures, submitted to Phys. Rev.