Time-Delayed Four-Wave Mixing Using Intense Incoherent Light

摘要

Time delayed four-wave mixing (TDFWM) on the 3S-3P transition in Na vapor has been studied using intense 7 nsec pulses from a broadband laser. Large scale 1.9 psec modulation associated with the fine structure of the 3P state is observed throughout. At low buffer-gas pressures and low Na-vapor temperatures, pulse induced relaxation effects are observed while at higher Na vapor temperatures an anomalous response develops. In the Normal region the TDFWM signal is interpreted in terms of either accumulated free decays or photon echoes. We estimate the relaxation induced by the excitation pulses. Keywords: Optical coherent transients; Photons echoes; Incoherent excitations; Incoherent light; Four wave mixing; Time-delayed four-wave mixing; Accumulated photon echo; Accumulated free decay; Pulse induced relaxation; Optical noise; Sodium vapor; and Reprints.