Yu Shaogang, Titze Michael, Zhu Yifu, Liu Xiaojun, Li Hebin
Opt Express. 2019 Sep 30;27(20):28891-28901. doi: 10.1364/OE.27.028891.
Optical double-quantum two-dimensional coherent spectroscopy (2DCS) was implemented to probe interatomic dipole-dipole interactions in both potassium and rubidium atomic vapors. The dipole-dipole interaction was detected at densities of 4.81×10 cm and 8.40×10 cm for potassium and rubidium, respectively, corresponding to a mean interatomic separation of 15.8 m or 3.0×10 for potassium and 6.1 m or 1.2×10 for rubidium, where is the Bohr radius. The experimental results confirm the long range nature of the dipole-dipole interaction, which is critical for understanding many-body physics in atoms/molecules. The long range interaction also has implications in atom-based applications involving many-body interactions. Additionally, we demonstrated that double-quantum 2DCS is sufficiently sensitive to probe dipole-dipole interaction at densities that can be achieved with cold atom in a magneto-optical trap, paving the way for double-quantum 2DCS studies of cold atoms and molecules. The method can also open a new avenue to study long-range interactions in solid state systems such as quantum dots and color centers in diamonds.
采用光学双量子二维相干光谱（2DCS）来探测钾和铷原子蒸气中的原子间偶极-偶极相互作用。在钾和铷的密度分别为4.81×10 cm 和8.40×10 cm 时检测到了偶极-偶极相互作用，这分别对应于钾的平均原子间距为15.8 m或3.0×10 ，以及铷的平均原子间距为6.1 m或1.2×10 ，其中 为玻尔半径。实验结果证实了偶极-偶极相互作用的长程性质，这对于理解原子/分子中的多体物理至关重要。这种长程相互作用在涉及多体相互作用的基于原子的应用中也具有重要意义。此外，我们证明了双量子2DCS在磁光阱中冷原子所能达到的密度下，对探测偶极-偶极相互作用具有足够的灵敏度，为冷原子和分子的双量子2DCS研究铺平了道路。该方法还可以为研究固态系统（如量子点和金刚石中的色心）中的长程相互作用开辟一条新途径。
