Study of collisional redistribution using two-photon absorption with a nearly-resonant intermediate state

Abstract

The authors report studies of collision-induced features of the $3{S}_{\frac{1}{2}}\ensuremath{\rightarrow}3{P}_{\frac{1}{2}}\ensuremath{\rightarrow}4{D}_{\frac{3}{2}}$ two-photon absorption in atomic-sodium vapor undergoing collisions with several rare-gas perturbers. The results yield the collisional redistribution function which describes the nonresonant excitation of the $3{P}_{\frac{1}{2}}$ intermediate state. Good agreement with theory is obtained only if effects of $3{P}_{\frac{1}{2}}\ensuremath{\leftrightarrow}3{P}_{\frac{3}{2}}$ state-changing collisions are included in the calculations. Results are used to obtain a value for a pressure-broadening coefficient in the Na-Kr system.