在這項工作中，我們研究了在熱室和磁光阱 (MOT) 中具有倒梯型激發的銣雷德堡原子。這種激發方式允許藉由較短波長（偵測）雷射將原子從基態激發到中間態，然後跟著長波長（耦合）雷射到達雷德堡態藉由躍遷 5S1/2 → 6P1/2 → nS 或 nD。在我們的實驗中，耦合雷射為 1010 nm，它由超過 1 W 的放大外腔二極管雷射 (ECDL) 產生，並鎖頻在波長計上。 421 nm 偵測雷射光由倍頻 840 nm 半導體雷射系統產生，能夠掃描足夠寬的頻率範圍。
通過觀察蒸氣室中包括三對 nS-nD 能階的 EIT 光譜，已經成功地產生了 87Rb 的各種雷德堡躍遷。藉由利用在 MOT 中更靈敏的陷阱損失檢測，還觀察到 92S 的微弱躍遷，並且發現 nD 狀態的 EIT 強度大約是 nS 狀態的 2.4 倍。還研究了 EIT 信號與偵測光功率的關係，並顯示為線性關係。我們研究的雷德堡態的絕對頻率被測量到 32 MHz 的精度，並且與更新的量子缺陷理論 (QDT) 一致。這項工作旨在研究異核雷德堡原子之間的相互作用，例如銣 (Rb) 和鉀 (K) 在更大的主量子數 (n) 下，其中 Förster 能量轉移變得很重要。

In this work, we study Rubidium Rydberg atoms with the inverted ladder-type excitation in both a hot cell and magneto-optical trap (MOT). This excitation scheme allows exciting the atoms from the ground state to the intermediate state by a shorter-wavelength (probe) laser, then following a long-wavelength (coupling) laser to reach the Rydberg states, through the transition 5S1/2 → 6P1/2 → nS, or nD. In our experiments, the coupling laser is 1010 nm, which was generated from an amplified external-cavity diode laser (ECDL) with more than 1 W, and was locked to a wavelength meter. The 421 nm probe laser is from a frequency-doubled 840 nm semiconductor laser system, which is capable of scanning in a sufficiently wide range of frequencies.
Various Rydberg transitions of 87Rb have been successfully produced via observing the EIT spectrums, including three pairs of nS-nD levels, in the vapor cell. The weak transition to the 92S state was also observed by utilizing the more sensitive trap loss detection in the MOT. The magnitude of EIT spectrums of nD states was found to be roughly 2.4 times larger than that of nS states. The probe power dependence of the EIT signal was also studied and showed as a linear proportion. The absolute frequencies of the Rydberg states under our investigation were measured to the accuracy of 22 MHz and in good agreement with the updated quantum defect theory (QDT). This work is toward the study of the interaction between dual species Rydberg atoms, such as Rubidium (Rb) and Potassium (K) at a large principal quantum number (n), where the Förster energy transfer becomes important.

摘要 I
Abstract II
Acknowledgments III
Contents IV
List of Tables V
List of Figures VI
Chapter 1. Introduction 1
1.1 Motivation 1
1.2 Outline 2
Chapter 2. Theoretical Background 4
2.1 Rubidium Characteristics 4
2.2 Rydberg Atoms 6
2.3 Electromagnetically Induced Transparency 8
2.4 Inverted Ladder-Type Excitation 10
Chapter 3. Experimental Apparatus 12
3.1 Blue Laser System 12
3.1.1 Master Laser and Tapered Amplifier System 12
3.1.2 Second Harmonic Generation (SHG) 13
3.2 NIR Laser System 15
3.2.1 External-Cavity Diode Laser 15
3.2.2 Tapered Amplifier 17
3.3 Rubidium Cell 19
Chapter 4. Rydberg Excitation In Rubidium Cell 20
4.1 Experimental Setup 20
4.2 Results And Discussion 24
Chapter 5. Rydberg Excitation In Rubidium MOT 35
5.1 Experimental Setup 35
5.2 Results And Discussion 35
5.3 Absolute frequencies measurement of transitions between the ground state and Rydberg states 37
Chapter 6. Conclusion And Future Work 39
6.1 Conclusion 39
6.2 Future work 40
References 41

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