Experimental Investigation Of Active Vibration Isolation System For High Precision Cold Atom Interferometers

Since 1991, atom interferometers have been applied in geographic measurements, inertial navigation, general relativity test, and fundamental physics constant determination. A high-resolution atom interferometer can be used to experimentally test equivalence principle, while a serial complex technical problem must be solved in advance to improve experimental precision. Among these problems, vibrational noise is one of the key parameters which affect the precision of atom interferometry measurements. To improve the precision of atom interferometry measurements, this thesis experimentally investigated an active vibration isolation system for high precision atom interferometers, successfully developed a stable ultra-low-frequency active-vibration-isolation experimental system, and applied this system in atom interferometer based gravity measurements. The main novel results of this thesis can be listed as follows:1. A high-precision atom interferometer was developed, an atom fountain with launching height up to 12 m was realized, and the affection of vibration noise on atom interference signals was investigated.2. The mechanizem of nosie propagation in atom interfrometers was investigated. The charicteristics of atom interferometers with different configurations were analyzed. The influence of vibration noise and laser phase noise on atom interferometer based gravitaional wave detection was studied; the dependence of gravitational wave detection noise on the seperation distance between two atom interferometers under different noise backgrounds were investigated.3. An active vibration isolation system was designed and realized. This vibration isolation system has higher stability, ultra-low-frequency response, and powerful ability for suppressing background vibration noise, its intrinsic frequency is as low as 0.015 Hz, it suppresses the low frequency vibration of the background by at least 100 times, and the vibrational noise is down to 1×10-9 g/(?)Hz among the frequency range of around 1 Hz. This active vibration isolation system has been successfully used in atom interferometry measurement experiments, and greatly improved the precision of measurements.4. A FPGA-based sequential control system for high-precision atom interferometer was developed. This system supplied a powerful guarantee for the smooth runing of the high precison atom interferometer.