Orientation and alignment relaxation of the3P2states of sodium measured at high vapor densities

Orientation and alignment relaxation cross sections have been obtained for the $3{}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}$ and $3{}_{}{}^2{}_{}{}^{}P_{\frac{3}{2}}^{}{}_{}{}^{}$ states of sodium by measuring resonance broadening of Hanle-effect signals at vapor densities up to about ${10}^{15}$ atoms/${\mathrm{cm}}^3$. In order to avoid reabsorption of the resonantly scattered light, the Hanle effect is measured in a region close to the wall of a specially constructed vapor cell. The width of the Hanle-effect signals is found to vary linearly with vapor density. The resulting cross sections for orientation and alignment relaxation are compared with theory.