The Investigation Of Energy Pooling Collision In Sodium Vapor

Energy Pooling Collision is a basic mechanic of the interaction between atom and field, it is efficiency means to provide the useful information about atomic structure and the interaction between atoms. It also takes an important role in the dynamic process of chemical reaction radiated by laser, also for the understanding of the atom and molecular physics as well as the stellar process. Energy Pooling Collision can make a new way in the inquest for the new ultraviolet laser radiation source, since which is efficiency means producing short wave radiation.This paper is aimed to interpretation the mechanism of the dependence of Energy Pooling Collision on external surroundings (such as temperature, laser power), the new results obtained are as followings. Fluorescence signals transiting from higher states (5S, 5P,4P, and 4D) populated by Energy Pooling Collision decay to lower states were observed when resonantly exciting the sodium 3P1/2 state by a narrow linewidth CW laser in sodium vapor. The excitation spectroscopes and the fluorescence spectroscopes at different temperature and laser power were recorded. A model of approximate two levels system was put forward for energy collision transfer in the view of resonant excitation dynamics. By analyzing the experiment results using the related rate equations in detail, the calculated relationship of collision transfer rates changing with temperature and laser power in theory is agreement with experiment results. The physical interpretation for the changes is also given.This paper also gives the special aspects of the fluorescence signal of 3P3/2 state changing within certain temperature and laser power variation in order to find the contribution of the 3P3/2 and 3P1/2 during energy pooling collision. The postpone of Radiation Self-Trapping Effect of resonant state was found after properly increase laser power at certain temperature. For the first time, the explanation for the changing apt of the collision transfer rates of sodium 3P3/2 state was given in this temperature and laser power variation using the model of three levels system. The character of heavily radiation trapping which caused the acceleration of atoms was observed athigh temperature via high-resolution laser spectroscopy technique. The acceleration of atoms caused the energytransfcr ratc diminishes of zero velocity atoms. From the view of energy transfer, the change of atom velocitydistribution was analyzed.Using matrix equation, we have studied the effect of three-photon interference formed by two-photon probe field, one coupling field and one external driving field interaction on the EIT inA-type system. The analysis result shows that the three-photon interference can cause the asymmetry of EIT, and the numerical results is good agreement with the theoretical analysis.