Polarization dependence of near-resonant two-photon absorption of Na 2 vapor

Abstract

We report theoretically and experimentally on the polarization dependence of two-photon absorption of diatomic molecules for the case where only one intermediate rotationvibration level (off-resonance Δ) contributes to the transition strength. In this case, in the classical limit ( J → ∞), the polarization between is (i) independent of the electronic symmetries, and (ii) it can be different for the regime Δ ⪢ Δ v D and Δ ≈ Δν D, due to velocity-tuning. The experiments have been performed on the 16601.88 cm −1 two-photon transition of Na 2; they show that this transition belongs to the Q-branch.