| Atom gravity gradiometer is a new type of gravity gradient measurement instrument. It is of great significance and broad application prospect in many fields, such as fundamental physical research, resources exploration, and environment monitoring. In an atom gravity gradiometer, Raman laser pulses are employed to split, reflect and recombine cold atom clouds to realize interference, to extract gravity and gravity gradient values from the interference fringe’s phase. The noise of Raman lasers’ intensity, phase and frequency are very important noise sources in the atom gravimeter and the atom gravity gradiometer, therefore, the measurement accuracy of the gravimeter and gradiometer are strongly influenced by the Raman lasers’ specifications. According to the requirement of the atom gravity gradiometer for Raman lasers, I designed and realized a compact Raman laser system with high power, low phase noise, narrow linewidth for the measurement of the horizontal component of gravity gradient, the main progress of this thesis include follows:1. The influence of various experimental parameters on the sensitivity of gravity gradient measurement, and the acquirement of an atom gravity gradiometer for Raman laser parameters are analyzed theoretically.2. A compact Raman laser system is designed, and the relevant developing and testing of semiconductor laser, laser power amplifier, optical fiber electro-optic modulator are carried out.3. A Raman laser system used for the atom gravity gradiometer is successfully developed, the intensity stability, the phase noise, the frequency noise and other parameters of Raman laser system are measured and evaluated.4. The influence of the Raman laser system on the gravity gradient measurement are analyzed, where, the single measurement noise induced by Raman laser phase noise, intensity fluctuation noise and frequency noise are 3 E,12 E and 5 E respectively, which can satisfy the requirement for sub-E level gravity gradient measurement. |
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