Sadler L E, Higbie J M, Leslie S R, Vengalattore M, Stamper-Kurn D M
Department of Physics, University of California, Berkeley, California 94720, USA.
Phys Rev Lett. 2007 Mar 16;98(11):110401. doi: 10.1103/PhysRevLett.98.110401. Epub 2007 Mar 12.
We present coherence-enhanced imaging, an in situ technique that uses Raman superradiance to probe the spatial coherence of an ultracold gas. Applying this technique, we identify the coherent portion of an inhomogeneous degenerate (87)Rb gas and obtain a spatially resolved measurement of the first-order spatial correlation function. We find that the decay of spin gratings is enhanced in high density regions of a Bose-Einstein condensate, and ascribe the enhancement to collective atom-atom scattering. Further, we directly observe spatial inhomogeneities that arise generally in the course of extended-sample superradiance.
我们展示了相干增强成像技术，这是一种原位技术，利用拉曼超辐射来探测超冷气体的空间相干性。应用该技术，我们识别出非均匀简并（87）Rb气体的相干部分，并获得了一阶空间关联函数的空间分辨测量结果。我们发现，在玻色-爱因斯坦凝聚体的高密度区域中，自旋光栅的衰减增强，并将这种增强归因于原子间的集体散射。此外，我们直接观察到了在扩展样品超辐射过程中普遍出现的空间不均匀性。
