Feshbach共振操控超冷分子的光缔合

发布时间：2018-06-04 21:32

本文选题：超冷铯分子 + 光缔合　；参考：《山西大学》2016年博士论文

【摘要】：超冷分子因为其具有极低的温度和丰富的振转能级,使得人们可以在量子机制下更为本质地研究分子间的相互作用和分子反应的动力学过程,而且已经被应用于精密测量、多体物理、量子模拟、量子计算和量子信息工程等众多物理前沿问题的研究,引起了科学家们广泛的兴趣。目前,制备超冷分子的主要方法有：超冷原子的光缔合和Feshbach共振以及经二者有效结合形成的受激拉曼绝热转移。考虑到受激拉曼绝热转移的初始态为短寿命的Feshbach分子态,理论上基于Feshbach共振增强的光缔合效应,提出了具有长寿命的超冷散射态原子在Feshbach共振附近的受激拉曼绝热转移。本论文以研究Feshbach共振操控超冷铯分子的光缔合为目的,实现了Feshbach共振增强的光缔合。将经过简并的三维拉曼边带冷却的铯原子样品装载到磁悬浮交叉的光学偶极阱中,测量了光阱中超冷铯原子的光缔合光谱和d波Feshbach共振,研究了超冷铯原子在d波Feshbach共振附近的光缔合,获得了Feshbach共振增强的光缔合,同时为了解释Feshbach共振诱导光缔合中的Fano效应,建立了原子-分子系统中由磁光量子干涉形成的Fano共振理论。此外,针对光缔合过程中光缔合激光光强诱导原子-分子共振跃迁频率偏移的现象,我们详细研究了外部均匀偏置磁场和Feshbach共振对超冷分子光缔合过程中光致频移率的影响,获得了外磁场和Feshbach共振可控制的光致频移,利用Fano共振理论很好的解释了Feshbach共振可控制的光致频移。本论文的主要工作可以概括如下：1.利用经优化拉曼激光失谐后的简并的三维拉曼边带冷却技术,将磁光阱中的铯原子样品冷却到1.7gK,并制备到Zeeman能级F=3,mF=3上。这样就可以有效的抑制处于Zeeman能级F=3,mF=3上铯原子的非弹性吸热碰撞,且能够提高接下来光学偶极阱装载的效率。2.通过磁悬浮技术将经优化的简并的三维拉曼边带冷却后的铯原子样品高效的装载到交叉的大体积光学偶极阱中,实验上测量了不同的磁悬浮磁场对磁悬浮光学偶极阱装载率的影响,并从理论上给出了很好的解释。3.研究了光阱中超冷铯原子的光缔合和Feshbach共振,获得了超冷铯分子长程激发态0g-的振转光谱,观测到处于能级F=3,mF=3上的铯原子在48G处的d波Feshbach共振。4.研究了超冷铯原子d波Feshbach共振附近的光缔合,获得了Feshbach共振增强的光缔合,通过考虑Feshbach共振对光缔合中Franck-Condon因子的影响,解释了Feshbach共振增强的光缔合。建立了原子-分子系统中由磁光量子干涉引起的Fano共振模型,对Feshbach共振附近光缔合率展现出的Fano效应进行了解释；同时,测量了不同均匀偏置磁场下的光缔合,发现了大范围外部磁场可控制的光缔合,并对其进行了分析。5.测量了外部均匀偏置磁场对超冷铯原子光缔合过程中光致频移的影响,发现可大范围调谐的外部磁场可以被用来控制该频移率；同时,研究了Feshbach共振对光致频移率的影响,用原子-分子系统中的Fano共振理论对Feshbach共振附近光致频移率的变化进行了模拟,实验和理论符合很好。
[Abstract]:Because of its extremely low temperature and rich vibrational energy level, supercooled molecules can study the intermolecular interaction and the kinetic process of molecular reactions more essentially under the quantum mechanism, and have been applied to many physical frontiers such as precision measurement, multibody physics, quantum simulation, quantum computing and quantum information engineering. The research on the problem has aroused wide interest of scientists. At present, the main methods for preparing supercooled molecules are: the optical association of supercooled atoms and the Feshbach resonance and the stimulated Raman adiabatic transfer formed by the effective combination of two. Considering the short life Feshbach molecular state of the initial state of the stimulated Raman adiabatic transfer, the theory is based on the Feshb The enhanced optical association effect of ACh resonance is proposed. The stimulated Raman adiabatic transfer of ultra cold scattering atoms with long life near the Feshbach resonance is proposed. This paper aims to study the optical association of the ultra cold cesium molecules controlled by Feshbach resonance, and realizes the Feshbach resonance enhanced optical association. The atomic samples are loaded into the optical dipole trap of the magnetic levitation cross, and the optical association spectra and d wave Feshbach resonance of the ultra cold cesium atoms in the optical trap are measured. The optical association of the supercooled cesium atoms near the d wave Feshbach resonance is studied. The Feshbach resonance enhanced photoassociation is obtained, and the Fano effect in the Feshbach resonance induced light association is also understood. The Fano resonance theory formed by magneto-optical quantum interference in the atomic and molecular system is established. In addition, in view of the phenomenon that the light association laser intensity induces the frequency shift of the atomic and molecular resonance transition in the light association process, we have studied the frequency shift rate of the external uniform bias magnetic field and the Feshbach resonance in the process of the hyper cold molecular light association. The effect of the external magnetic field and Feshbach resonable optical frequency shift is obtained. Using the Fano resonance theory, the controllable frequency shift of Feshbach resonances is well explained. The main work of this thesis can be summarized as follows: 1. using the degenerate three-dimensional Raman side band cooling technology after the detuning of the optimized Raman laser, the cesium source in the magneto optical trap is used. The sub samples are cooled to 1.7gK and are prepared on the Zeeman level F=3, mF=3. This can effectively inhibit the inelastic absorption of cesium atoms on the Zeeman level F=3, mF=3, and can improve the efficiency of the next optical dipole trap loading.2. through the magnetic levitation technology to reduce the cesium atomic sample after the optimized degenerate three dimensional Raman side band. The effect of different magnetic levitation magnetic fields on the loading rate of magnetic suspended optical dipole is experimentally measured with high efficiency loading into a cross large optical dipole trap, and a good explanation of.3. is given in theory to study the optical association and Feshbach resonance of supercooled cesium atoms in the optical trap. The long range excited state of 0g- of the supercooled cesium molecule is obtained. The d wave Feshbach resonance.4. at 48G on the energy level F=3 and mF=3 has been observed to study the optical association near the d wave Feshbach resonance of the supercooled cesium atom, and the Feshbach resonance enhanced optical association was obtained. The Feshbach resonance enhanced optical connective was explained by considering the effect of Feshbach resonance on the Franck-Condon agent in the optical association. Fano resonance model induced by magneto-optical quantum interference in atomic and molecular systems is established to explain the Fano effect shown by the optical association rate near the Feshbach resonance. At the same time, the optical association of different uniform bias magnetic fields is measured, and the optical association of the magnetic field controlled by a large external magnetic field is found and the.5. measurement is analyzed. The effect of the external uniform bias magnetic field on the photoinduced shift in the optical association process of the supercooled cesium atom is found. It is found that the wide tunable external magnetic field can be used to control the frequency shift rate. At the same time, the effect of Feshbach resonance on the frequency shift rate is studied. The optical frequency shift near the Feshbach resonance is used by the Fano resonance theory in the atomic molecular system. The change of rate is simulated, and the experiment and theory are in good agreement.
【学位授予单位】：山西大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O561

【参考文献】