The efficiency of evaporative cooling, which is used for the creation of a Bose-Einstein condensate, depends strongly on the number of particles at the start of the evaporation. A high efficiency can be reached by filling the magneto-optical trap with a large number of atoms and subsequently transferring these atoms to the magnetic trap as efficiently as possible. In our case (for sodium) this efficiency is limited to $1∕3$ , because the magnetic substates of the $F=1$ state, which is used in the trapping process, are equally populated. This limit can be overcome by spin-polarizing the sample before the transfer. For sodium atoms, however, the improvement is very small when it is done in a small magnetic field due to the large number of optical transitions in combination with the high optical density. In this paper, we describe spin-polarizing sodium atoms in a high magnetic field. The transfer efficiency is increased by a factor of 2. The high magnetic field makes the process also more robust against variations in the magnetic field, the laser frequency, and the polarization of the laser beam.The efficiency of evaporative cooling, which is used for the creation of a Bose-Einstein condensate, depends strongly on the number of particles at the start of the evaporation. A high efficiency can be reached by filling the magneto-optical trap with a large number of atoms and subsequently transferring these atoms to the magnetic trap as efficiently as possible. In our case (for sodium) this efficiency is limited to $1∕3$, because the magnetic substates of the $F=1$ state, which is used in the trapping process, are equally populated. This limit can be overcome by spin-polarizing the sample before the transfer. For sodium atoms, however, the improvement is very small when it is done in a small magnetic field due to the large number of optical transitions in combination with the high optical density. In this paper, we describe spin-polarizing sodium atoms in a high magnetic field. The transfer efficiency is increased by a factor of 2. The high magnetic field makes the process also more robust against variations in the magnetic field, the laser frequency, and the polarization of the laser beam.

arXiv:physics/0603255Physical Review AJun 28, 200611 citations

Magnetic trapping of spin polarized neutral atoms and its limits

V. E. Shapiro

Physical Review AJan 1, 19950 citations

Experiments with a laser cooled cloud of atoms

Vasant Natarajan A, Ayan Banerjee, Umakant D. Rapol

We discuss two experiments that can be performed using a cloud of laser-cooled and trapped atoms, namely Bose-Einstein condensation (BEC) and search for a permanent Electric Dipole Moment (EDM). BEC can be observed in Rb atoms in a magnetic trap by using forced evaporative cooling to continuously lower the temperature below the condensation limit. The cloud is cooled by preferentially ejecting the hottest atoms from a magnetic trap. The magnetic trap is loaded with laser-cooled atoms from a magneto-optic trap. The EDM experiment can be performed with a laser-cooled cloud of Yb atoms. The atoms are spin polarized and the precession of the spin is measured in the presence of a strong electric field applied perpendicular to the spin direction. The use of laser-cooled atoms should greatly enhance the sensitivity of the experiment.We discuss two experiments that can be performed using a cloud of laser-cooled and trapped atoms, namely Bose-Einstein condensation (BEC) and search for a permanent Electric Dipole Moment (EDM). BEC can be observed in Rb atoms in a magnetic trap by using forced evaporative cooling to continuously lower the temperature below the condensation limit. The cloud is cooled by preferentially ejecting the hottest atoms from a magnetic trap. The magnetic trap is loaded with laser-cooled atoms from a magneto-optic trap. The EDM experiment can be performed with a laser-cooled cloud of Yb atoms. The atoms are spin polarized and the precession of the spin is measured in the presence of a strong electric field applied perpendicular to the spin direction. The use of laser-cooled atoms should greatly enhance the sensitivity of the experiment.

Jan 1, 19990 citations

Spin-Polarized Atoms in a Circularly Polarized Optical Dipole Trap

Kristan L. Corwin, S. J. M. Kuppens, D. Cho +1 more

WORLD SCIENTIFIC eBooksJan 1, 20080 citations

Magnetic Trapping of Neutral Atoms

Harold J. Metcalf, P. van der Straten

Graduate texts in contemporary physicsJan 1, 19993 citations

1∕3

, because the magnetic substates of the

F=1

state, which is used in the trapping process, are equally populated. This limit can be overcome by spin-polarizing the sample before the transfer. For sodium atoms, however, the improvement is very small when it is done in a small magnetic field due to the large number of optical transitions in combination with the high optical density. In this paper, we describe spin-polarizing sodium atoms in a high magnetic field. The transfer efficiency is increased by a factor of 2. The high magnetic field makes the process also more robust against variations in the magnetic field, the laser frequency, and the polarization of the laser beam.