Optical pumping for intense polarized ion sources

Laser optical pumping without buffer gas in dense (NL>10/sup 12/ atoms/cm/sup 2/) sodium vapor targets was investigated. The atomic polarization of the target was determined from the Faraday rotation angle of a second dye laser tuned midway between the sodium D-lines. Substantial polarizations were measured even though the pump laser bandwidth (approx. 1 MHz) was much smaller than the Doppler and hyperfine broadened sodium absorption line (approx. 3 GHz). Theoretical calculations based on rate equations in an idealized 3-level, ..lambda..-type system adequately reproduce the data. These calculations predict very high polarizations (P>0.8) at power levels produced in commercially available ring dye lasers