The Moving Mean Effect Of Coated

This thesis focuses on the profound study in linewidth of narrow peak of Electro-magnetically Induced Transparency dual-structure in coated Rubidium vapor cell and the discovery of a variety of nonlinear effect in motional averaging via Monte Carlo Simulation and experiment.The narrow linewidth is regarded as a key factor of enhancing the efficiency of slow light and light storage so excellent condition can be formed by ultra-narrow linewidth caused by ultra-long longitudinal relaxation time in coated Rb vapor cell. This research is meaningful as it could set both theory and experiment foundation of slow light and light storage by acknowledging the effect of motional averaging to linewidth of coated cell EIT and studying the influence of power intensity, beam size and gradient field on narrow linwidth by simulation in theory and prove in experiment.In Chapter3, Monte Carlo Simulation is conducted for calculating the evolution of related physical quantity by emulatingthe motion of atom in vapor cell. The program, written by FORTRAN language, is used in a serial of research in the trend of EIT in vapor cell along with the change of Rabi frequency, beam size and gradient field, display a nonlinear effect with interactive factors in the motional averaging of atom system. Also, methods of weakening the fluctuation in Monte Carlo system are summarized through the error analysis and precision estimation.In Chapter4, the procedure of the establishment of the lab is introduced firstly: Self-designed heating system and magnetic system and delicate optics, using as the corresponding study in the trend of EIT in vapor cell along with the change of power intensity, beam size and gradient field, which, provide a remarkable coincide with the result in simulation, with an evident observation of nonlinear with interactive factors in motional averaging process.In Chapter5, analysis and conclusion of the result from simulation and experiment is made, which proved the motional averaging effect by the fact the range of linewidth broadening will decrease when beam size increases or power intensity increases, and the broadening in lnT/cm, however, shows a lower value than that in the well-accepted theory that the broadening induced by one Gauss of magnetic field is1.4MHz (equally illustrated as14Hz of broadening induced by one nano-tesla of magnetic field), regarding that the broadening induced by the gradient field could be reduced by motional averaging effect in low gradient field.