Theoretical Study On The Bloch-oscillations Based Atomic Gravimeter

High-precision absolute gravity measurement is of great significance to many fields such as resource exploration,inertial navigation,geophysics and metrology.Atomic gravimeter is an important means to achieve high-precision absolute gravity measurement.It includes atomic interference type absolute gravimeter and atomic Bloch oscillation type absolute gravimeter.Currently,the atomic interference type absolute gravimeters is fairly mature,but the evaluation of wavefront distortion effects is quite difficult.The Bloch oscillation type absolute gravimeters have relatively lower accuracy,but they have the advantage of measuring weak forces at short range.This thesis mainly studies the Bloch oscillation type absolute gravimeter.After the understanding of its principle,the systematic errors of the atomic gravimeter,especially the wavefront aberration effect,are analyzed,for the purpose of evaluating its potential power.The main works are as follows.(1)The energy band structure of atom in optical lattice and the process of Bloch oscillation under the presence of gravity are derivated.The oscillation frequency is proportional to the acceleration of gravity.The principle of measuring the acceleration based on Bloch oscillation is introduced and the Related experimental works in other groups are summarized.Inspired by the physical picture of explaining Bloch oscillations using Bragg diffraction,ascheme for observing atomic oscillation which is similar to Bloch oscillation is proposed.This scheme is based on two-photon Raman excited transitions.It can be used to measure gravitational acceleration and take full advantage of internal states labeling for detection.Our scheme provides a new way for the oscillation type atomic gravimeter.(2)The current limits of measurement accuracy of the Bloch oscillation type atomic gravimeter are analyzed.By referring to the typical experimental parameters of related groups working on Bloch oscillation atomic gravimeter,we theoretically analyzed the systemtic errors of this type of gravimeter.Main focuses are taken on the wavefront aberration effect that was not considered by other groups.And a preliminary result is carried out by using numerical simulation.The result shows that the wavefront aberration effect in the Bloch oscillation atomic gravimeter may be as high as10?Gal.