Optical manipulation of helium(2(3)S) atoms with a diode laser

Abstract

A commercial Spectra Diode Laboratories, 1.083 $\mu$m diode laser has been used to efficiently spin polarize an atomic beam of He(2\sp3S) 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)