Coherent Control Of Three-dimensional Atomic Localization

Atomic localization is a significant branch in the field of laser physics and quantum optics.Because of the space-dependent atom-field interaction,the position probability distribution of the atom can be directly determined by measuring the probe absorption.In this thesis,based on atomic coherence effect,we have mainly proposed three schemes for 3D atom localization.1.Based on electromagnetically induced transparency,a scheme to three-dimensional atom localization in four-level inverted Y-type atomic system is proposed.Because of the space-dependent atom-field interaction,the position probability distribution of the atom can be directly determined by measuring the probe absorption.The results show that the atom can be localized at a particular position by properly adjusting the detuning of probe field and intensity of the coupling field,and 3D localization model with different structures,such as Ellipsoidal,vase-shaped,and hourglass-shaped,can be obtained.Moreover,the maximum probability that an atom will be detected at a particular position is increased to 100%by choosing appropriate phase of driving fields.2.In three orthogonal standing wave field driven four-level N-type atomic systems,high precision and high resolution three-dimensional atom localization is achieved.According to the different coupling modes between standing wave field and atomic energy-level transition,we discuss two cases:(1)two orthogonal standing wave fields are coupled with the same energy-level transition,and another standing wave field is coupled with another energy-level transition.(2)Three orthogonal standing wave fields are coupled to the same energy-level transition.By properly adjusting the phase of standing wave field,high precision and high resolution three-dimensional atom localization can be achieved.3.Under the action of incoherent pumping field,two-dimensional and three-dimensional atom localization is investigated in a five-level atomic system.Two orthogonal standing-wave fields are applied to couple the same atomic energy-level transition,and another standing wave field coupling another energy-level transition.In two-dimensional space,we find that the maximum probability of finding an atom can reach 100%by choosing appropriate system parameters,while three-dimensional space,the maximum probability of atoms being detected is 50%.