Detailed look at aspects of optical pumping in sodium

Calculations and measurements are presented of the increase in F{}=1 ground-state population as a function of incident laser intensity in optically pumped sodium. The calculations involve numerical integration of a multilevel version of the optical Bloch equations. Agreement between experiment and theory is good when proper account is taken of the residual Doppler width in the atomic beam, which causes a larger increase in the F{}=1 population. The F{}=1 population increases by 3.5% at 35 mW/cm², the highest laser intensity investigated.