原子干涉重力測量原理性實驗研究

1、華中科技大學(xué)博士學(xué)位論文原子干涉重力測量原理性實驗研究姓名：周敏康申請學(xué)位級別：博士專業(yè)：理論物理指導(dǎo)教師：胡忠坤;羅俊2011-03-30II華 中 科 技 大 學(xué) 博 士 學(xué) 位 論 文 Abstract The local gravity acceleration g is a key parameter for describing the earth’s gravity field, while the accuracy o

2、f g measurement is dependent on the absolute gravimeters. In recent years, atom interferometry gravimeters have been proved to be a useful tool for absolute gravity measurements. Because of its high potential sensitivity

3、, we are trying to develop a cold atom gravimeter in our cave lab for precision gravity measurements and gravitational experiments. The cold atom gravimeter is based on the atom interferometry technology by coherently d

4、riving the free-falling cold atoms with phase locked Raman beams. By compensating the g induced phase with the well controlled Raman lasers’ phase in an atom interferometer, we can find the center of the interferometry f

5、ringe, and then get the absolute value of g precisely. In order to experimentally realize an atom inrerferometry gravimeter, cold atoms were prepared in a magnetic-optical trap, launched upward to form an atom fountain,

6、and then coherently manipulated by the / 2 / 2 π π π ? ?Raman pulses to obtain an atom interferometry fringe, while the local gravity was deduced from the interference signal. The experimental setup of atom fountain, th

7、e phase locked Raman lasers and the primary results of gravity measurement with our atom gravimeter are presented in this thesis, which shows that: 1) about 108 atoms with temperature of 7μK have been launched to a heig

8、ht of 1m by the cold atom fountain; 2) Raman lasers with low phase noise of -90dBc/Hz between 100Hz to 100kHz are realized; 3) the resolution of the atom gravimeter is 9 6 10 g ? ×within 203s integration time, and

9、8 days earth-solid-tide data was also recorded by our gravimeter. In order to improve the resolution of this gravimeter, we have analyzed the influences of many possible noise sources. It shows that the sensitivity of o

10、ur gravimeter is currently limited by the seismic noise. In addition, we have experimentally demonstrated that the magnetic field sensitive atom interferometer could be used to precisely map the magnetic field in vacuum,