Selected Excitation And Coherent Control Of Rydberg Alkali Metal Atoms In Microwave Field

To control population transition effectively from one quantum state to another specific quantum state, notonly for the design and control of chemical reaction process and the product is very important, but also foratom optics and quantum optics in the preparation of a specific quantum state, coherent quantum statemanipulation, and so of great significance.In this thesis, the B-spline expansion technique and the model potenial method of atom have been appliedto solve the Schr dinger equation of alkali metal atoms, the energy levels structure and wave functions of freealkali metal atom are calculated. Using the time-dependent multilevel approach (TDMA), the properties ofhigh excited states of and population transfer of alkali metal atoms in a microwave field are studied onnumerical calculation by the free wave functions as base vector. It shows that the method we used can beapplied to investigate the properties of alkali-metal atoms in external field. It shows also that the population isvery sensitive to the parameters of chirped rate and field amplitude, the population can be completelytransferred to the target state and be trapped there by changing the chirped rate and field amplitude.First, the energy levels and the wave functions of the lithium atoms are calculated, the level values are ingood agreement with the results of the quantum defect method and model potential. Then the highly excitedstate energy are calculated, the population transfer of quantum states of lithium atoms in the frequency chirpedmicrowave field are studied. At the initial moment, lithium atom is on the n=70sstate, the populationtransfer probability between different states in the different frequency chirped microwave field are calculated.We can draw the conclusion that coherent migration and control of the quantum state are connected with notonly the amplitude of the microwave field, but also the frequency parameters of the microwave field. When weselect the appropriate amplitude and frequency parameters, the population of the initial state can be completelytransferred to the target state. Each state plays a vital role in the transition and should is considered in thequantum state manipulation and control process.Second, energy levels and wave functions of the sodium atom are calculated, sodium atom is on the initialstate, excitation transfer and coherent migration of the sodium atoms are calculated in the different microwavefield, the manipulation and control of quantum state are obtained. The results show that the population betweenquantum states can be completely transferred by selecting the appropriate microwave field parameters. Finally, the energy levels and the wave functions of the potassium atom are calculated, the transition ofmulti-level system and each state of potassium atom in the chirped microwave field are calculated.In summary, the level structures and transition of highly excited states of the lithium, sodium, potassiumatoms are calculated. We can draw the conclusion that the time-dependent multilevel approach (TDMA), theB-spline expansion technique and the model potenial method of atom have been applied to study the propertiesof Rydberg alkali-metal atoms. It shows that the method can be applied to investigate the properties ofalkali-metal atoms in external field; It shows also that the population is very sensitive to the chirped rate andfield amplitude parameters, the population can be completely transferred to the target state and be trapped thereby changing the chirped rate and field amplitude parameters. Each state plays a vital role in the transition andshould is considered in the quantum state manipulation and control process.