【摘要】 冷原子重力梯度仪在地球科学与资源勘探、基础物理等领域均具有重要的应用价值。为提升系统的集成度与鲁棒性,利用单束冷却光构建了双金字塔构型磁光阱,实现了上下两团冷原子的同步制备。实验结果表明,利用该结构制备的上下两团冷原子的特性参数呈现显著相关性:原子数目的Pearson相关系数为0.92,横向与纵向温度的相关系数分别为0.70和0.73,水平与垂直中心位置的相关系数分别为0.90和0.85。上下原子团特性参数的一致性是提升重力梯度测量稳定性的关键。更多还原

【Abstract】 Objective Cold atom gravity gradiometers are of significant value in research fields such as Earth science,resource exploration,and fundamental physics.Traditional cold atom gravity gradiometers typically employ six pairs of counter-propagating laser beams for atomic cooling,which leads to complex optical paths,large system volumes,and high power consumption.Moreover,the preparation of cold atom clouds is highly sensitive to factors including beam alignment,power fluctuations of individual beams,polarization variations,and vibrations.In contrast,the pyramidal magneto-optical trap(MOT) configuration requires only a single cooling laser beam to generate the optical field necessary for cold atom preparation,thereby enhancing system integration and robustness.Methods After mechanical beam expansion and collimation,the output laser is incident into the vacuum chamber.The cooling beam is reflected by the pyramid prism,forming a standing wave in the horizontal direction.The central portion of the cooling beam passes through the pyramid prism and is reflected by a 0° mirror at the bottom,forming a vertical standing wave field.Combined with the gradient magnetic field,this configuration generates a six-beam counter-propagating optical field for cold atom cloud preparation.The dual pyramidal MOTs are separated vertically by 0.6 m,each supplied with an atomic beam from an independent two-dimensional MOT.Results and Discussions The characteristic parameters of the top and bottom cold atom clouds prepared using this structure exhibit significant correlations.The Pearson correlation coefficient for the atom number is 0.92(Fig.9).The correlation coefficients for the transverse and longitudinal temperatures are 0.70 and 0.73,respectively(Fig.10).The correlation coefficients for the horizontal and vertical center positions are 0.90 and 0.85,respectively(Fig.11).Conclusions This study demonstrates a dual magneto-optical trap driven by a single cooling laser beam.The prepared top and bottom cold atom clouds show strong correlations in key parameters,including atom number,cloud temperature,and cloud position.The synchronous fluctuations of these cold atom parameters can effectively suppress the impact of variations in interference signal-tonoise ratio,contrast,and measurement baseline on gravity gradient measurements,thereby improving the measurement stability.The observed differences in the properties of the top and bottom atom clouds may arise from several factors:disparities in atomic beam flux from the two-dimensional MOTs,non-uniform light intensity distribution due to beam divergence,and anisotropic potential wells caused by alignment errors of the pyramid prisms.更多还原