熱銣原子中Λ型電磁波引發透明的實驗研究

本論文是熱銣原子biphoton單光子源的前期基礎實驗。由於熱原子運動產生的都卜勒效應(Doppler effect)會使光場有額外的吸收損耗，這一點對於光子級別的實驗來說可能會是致命性，導致實驗徹底失敗。因此，研究熱原子中的電磁波引發透明效應(Electromagnetically Induced Transparency，簡稱EIT)並達到足夠高的透明度是非常必要的。本論文採用的EIT模型為Λ-type，為了得到與理論模型最接近的光與原子交互作用的機制，必須將Population集中在某單一的塞曼能階(Zeeman state)。如何利用光抽運(optical pumping)將Population集中在 |5S1/2F=2，m=2>是本論文的研究主要內容，我們藉由補償地磁減少拉莫爾進動(Larmor precession)和利用高頻正弦波調變幫浦場(Pump field)使高速度群原子的幫浦效果變好，讓Population集中在|5S1/2F=2，m=2>，最後我們得到最佳的EIT光譜，其穿透率達到76%。

關鍵字

電磁波引發透明

並列摘要

The main work of this thesis is one of the bases for a biphoton single-photon source experiment in hot rubidium atoms. Due to Doppler effect, the thermal atomic motion causes additionally-absorbed loss for the light field, which may be fatal for a photon-level experiment and lead to a complete failure in experiment. Therefore, it is necessary to improve the Electromagnetic Induced Transparency (EIT) performance to achieve a sufficiently high degree of transparency. In this thesis, a Λ-type model is used to demonstrate EIT and population must be concentrated in one single Zeeman state in order to get the closest interaction between light and atoms with theoretical model. The main contents of this thesis is using optical pumping to make the population concentrated in the |5S1/2F=2，m=2>. We improve the pumping effect for high-speed atoms, via compensating geomagnetic field to reduce Larmor precession and using a high-frequency sine-wave modulated pump field to make the population could be concentrated in the |5S1/2F=2，m=2>. Finally, we observe the optimal EIT spectrum with 76% transmission.

並列關鍵字

Electromagnetically Induced Transparency

參考文獻

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[4] Georg Heinze, Christian Hubrich, and Thomas Halfmann，“Stopped Light and Image Storage by Electromagnetically Induced Transparency up to the Regime of One Minute s”，PRL 111, 033601 (2013).

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[6] Yong-qing Li and Min Xiao，“Enhancement of nondegenerate four-wave mixing based on electromagnetically induced transparency in rubidium atoms”，Opt. Lett.21(14), 1064-1066 (1996).

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熱銣原子中Λ型電磁波引發透明的實驗研究

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