Optical pumping by a laser pulse traveling in a cavity

We have developed a general method to perform optical pumping by a pulsed laser with the aid of an optical cavity ( cavity- assisted optical pumping ). Optical pumping is achieved by repetitive interaction of a single laser pulse with a target material in the cavity. This method is demonstrated for manganese ions, Mn+, stored in a linear radio- frequency ion trap; about 108 ions are spin polarized by a 5- ns laser pulse via 7P(J). <- S-7(3) ( J= 3 or 4 ) transition in the ultraviolet region. The linewidth of the pulsed light source is broad enough to transfer the populations of lower hyperfine levels to the highest one ( F= 11/ 2 ) in the S-7(3) ground state; the nuclear spin is polarized as well.