Production of a Spin-Polarized Atomic Cr Beam Using Optical Pumping Methods

Jai Min Choi, Jang Myun Kim, Se Young Jeong +1 more

G. Baum, C. Denise Caldwell, W. Schröder

Hongying Yang, Yanhua Wang, Nan Zhao

Junpeng Zhao, Gang Liu, Jixi Lu +9 more

Abstract In an optically pumped alkali vapor cell with a high density of atoms, the attenuation of the pump light generates a spatially non-uniform distribution of the electronic spin polarization of alkali atoms, which is detrimental to biomagnetism applications of magnetometers as well as the hyperpolarization of noble gas atoms. Therefore, in this study, we propose a new scheme to generate a nearly uniform, unsaturated spin polarization region based on counter-propagating pump beams and atomic diffusion. A finite element method-based simulation is used to demonstrate the three-dimensional distribution of the spin polarization in a spherical cell. The effects of cell temperature and pump light power on the homogeneity of the spin polarization are studied. The distribution of spin polarization near the center of the cell is experimentally measured and a 1 cm uniform spin polarization region is achieved in the center of the cell. The uniformity of spin polarization in the center region of the cell increased by 50% compared with single beam pumping. The advantage of our proposed scheme is that it can generate an unsaturated uniform region of spin polarization in the center of a cell using a single species of alkali atoms.

David Bixler

A commercial Spectra Diode Laboratories, 1.083 $\mu$m diode laser has been used to efficiently spin polarize an atomic beam of He(2$\sp3$S) metastable atoms by optical pumping on the $\rm 2\sp3S\sb1\rightarrow2\sp3P\sb1$ (D1) transition. The diode laser is an InGaAs/GaAs strained multiquantum well with a distributed Bragg reflector to insure single longitudinal mode operation. The laser has been frequency stabilized to less than 1 MHz/hr drift. The helium metastable atom beam is produced by electron impact and the polarization is measured using a Stern-Gerlach analyzer. Atomic polarizations exceeding 97% have been obtained with $\sim$25 mW of power from the diode laser. A number of experiments currently under construction may also make use of the diode laser. These include the production of a spin polarized helium ion beam by optically pumping the metastable atoms in an rf discharge, and the trapping of helium metastable atoms in a magneto-optical trap (MOT).

Ganghua Mei, Huang Gui-long, Jia‐Min Wang +3 more

The production of a polarized 7 Li atomic beam in a strong magnetic field was experimentally studied by laser optical pumping of a single ground hyperfine F level. It was shown that nearly complete negative and partial positive polarizations of 7 Li atoms could be realized under appropriate conditions by this pumping scheme, which was in agreement with the rate equation calculations. Based on the analyses of transition probabilities, the maximum polarizations for various transitions and light polarizations were given.