發(fā)布時間：2018-06-04 21:32

  本文選題：超冷銫分子 + 光締合�。� 參考：《山西大學》2016年博士論文

【摘要】：超冷分子因為其具有極低的溫度和豐富的振轉能級,使得人們可以在量子機制下更為本質地研究分子間的相互作用和分子反應的動力學過程,而且已經被應用于精密測量、多體物理、量子模擬、量子計算和量子信息工程等眾多物理前沿問題的研究,引起了科學家們廣泛的興趣。目前,制備超冷分子的主要方法有：超冷原子的光締合和Feshbach共振以及經二者有效結合形成的受激拉曼絕熱轉移。考慮到受激拉曼絕熱轉移的初始態(tài)為短壽命的Feshbach分子態(tài),理論上基于Feshbach共振增強的光締合效應,提出了具有長壽命的超冷散射態(tài)原子在Feshbach共振附近的受激拉曼絕熱轉移。本論文以研究Feshbach共振操控超冷銫分子的光締合為目的,實現了Feshbach共振增強的光締合。將經過簡并的三維拉曼邊帶冷卻的銫原子樣品裝載到磁懸浮交叉的光學偶極阱中,測量了光阱中超冷銫原子的光締合光譜和d波Feshbach共振,研究了超冷銫原子在d波Feshbach共振附近的光締合,獲得了Feshbach共振增強的光締合,同時為了解釋Feshbach共振誘導光締合中的Fano效應,建立了原子-分子系統(tǒng)中由磁光量子干涉形成的Fano共振理論。此外,針對光締合過程中光締合激光光強誘導原子-分子共振躍遷頻率偏移的現象,我們詳細研究了外部均勻偏置磁場和Feshbach共振對超冷分子光締合過程中光致頻移率的影響,獲得了外磁場和Feshbach共振可控制的光致頻移,利用Fano共振理論很好的解釋了Feshbach共振可控制的光致頻移。本論文的主要工作可以概括如下：1.利用經優(yōu)化拉曼激光失諧后的簡并的三維拉曼邊帶冷卻技術,將磁光阱中的銫原子樣品冷卻到1.7gK,并制備到Zeeman能級F=3,mF=3上。這樣就可以有效的抑制處于Zeeman能級F=3,mF=3上銫原子的非彈性吸熱碰撞,且能夠提高接下來光學偶極阱裝載的效率。2.通過磁懸浮技術將經優(yōu)化的簡并的三維拉曼邊帶冷卻后的銫原子樣品高效的裝載到交叉的大體積光學偶極阱中,實驗上測量了不同的磁懸浮磁場對磁懸浮光學偶極阱裝載率的影響,并從理論上給出了很好的解釋。3.研究了光阱中超冷銫原子的光締合和Feshbach共振,獲得了超冷銫分子長程激發(fā)態(tài)0g-的振轉光譜,觀測到處于能級F=3,mF=3上的銫原子在48G處的d波Feshbach共振。4.研究了超冷銫原子d波Feshbach共振附近的光締合,獲得了Feshbach共振增強的光締合,通過考慮Feshbach共振對光締合中Franck-Condon因子的影響,解釋了Feshbach共振增強的光締合。建立了原子-分子系統(tǒng)中由磁光量子干涉引起的Fano共振模型,對Feshbach共振附近光締合率展現出的Fano效應進行了解釋；同時,測量了不同均勻偏置磁場下的光締合,發(fā)現了大范圍外部磁場可控制的光締合,并對其進行了分析。5.測量了外部均勻偏置磁場對超冷銫原子光締合過程中光致頻移的影響,發(fā)現可大范圍調諧的外部磁場可以被用來控制該頻移率；同時,研究了Feshbach共振對光致頻移率的影響,用原子-分子系統(tǒng)中的Fano共振理論對Feshbach共振附近光致頻移率的變化進行了模擬,實驗和理論符合很好。
[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.
【學位授予單位】：山西大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：O561

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本文編號：1978897