Research On The Detection System In Atom Interferometry Rotation Measurement

Atom interferometry rotation measurement achieves the rotation angular velocity accurate measurement based on Sagnac effect with high potential sensitivity. Atom interferometry rotation measurement can be widely used in inertial navigation, geophysical, basic physics research and other fields, and it is important in the development of science and technology applications.In our atom interferometry rotation measurement, atomic wave packet is splitted, refected and combined to form interference with the Raman light p2 ~ p~ p~ p2 pulses interact with atoms sequentially. Interference phase shift included angular velocity information. Atoms at one ground state are transitted to another ground state after the end of interference. Transition probability is determined by the interference phase shift. One can obtain interference fringes and extract interference phase through detecting atomic transition probabilities. The subject comes from the demand of atom interferometry rotation measurement on detection system. We use the normalized fluorescence detection method to achieve probability of atom in the two different ground states based on our previous work.This paper describes the basic principles of detection system in atom interferometry rotation measurement. Considering the atom interferometry gyroscope's mechanical design has a certain inclination, we need to improve optical design of detection system in order to meet the experimental need. We must make it miniaturization. At the same time, we must make it miniaturization increase the intensity of detection and repumper beam. Meanwhile we ensure the probe split to a ratio of 1:1. Owing to cross-coupling effects, we need to calibrate fluorescence collection system with single imaging. Experiments showed that when photodiodes' spacing is set at 13.4mm and the distance between two rectangular aperture slit is set at 21 mm, the cross-coupling effects between the two photodiodes are well avoided while the signal amplitude will not become too small. In the experiment, we have achieved single-level and double-level detection. About 71.1?10 atoms are detected corresponding to the integration of detected single-level TOF signal of28.1?10 V gs. Detection noise coming from the fluctuations of probe power, background, and quantum projection noise are analyzed theoretically. Atom interferometry rotation measurement's detection noise is assessed. Experiments show that when the loading time is 3000 ms, the detection noise is 0.011.In order to reduce the effect of the probe power fluctuations on atom interferometry rotation measurement, we use the scheme that detects simultaneously fluorescence signal of the two states atoms. A specific design will be given to improve the SNR to achieve shot noise limit. On the other hand, wave front aberration is a major error that can affect the system measuring accuracy. Using a phase shear detection method, we can simulate the changes of probability caused by wave front aberration versus the position of distribution. By observing the change pattern caused by wave front aberration, we can solve the system error caused by wave front aberration in experiment.