銣原子蒸氣之電磁誘發吸收研究

Electromagnetically Induced Absorption in Rubidium Gas

林國豐(Kuo-Feng Lin)

指導教授 ： 韓殿君

國立中正大學/理學院/物理學系/碩士(2015年)

摘要

本論文主要探討熱銣原子氣體中的電磁誘發吸收效應(electromagnetically induced absorption)。在實驗方面，先利用線偏振探測光進行吸收光譜測量。研究中發現小於銣原子自然線寬(約4 MHz)的強吸收峰。再者，我們使用相位移干涉術量測探測光經過銣原子造成之額外光學相位變化，且觀測到群折射率約為-1800的超光速現象(superluminal behavior)。
我們也以圓偏振探測光進行電磁誘發吸收效應的吸收光譜量測，並發現量測呈現隨耦合光強增強而更加分離的二吸收峰。為量測圓偏振探測光經過銣原子造成額外光學相位變化，本實驗因此引入偏振正交干涉術(polarization quadrature interferometry)。此外，我們也研究外加磁場下銣原子電磁誘發吸收效應的變化。研究發現，當增加磁場時，原本電磁誘發吸收的現象逐漸轉換成電磁誘發透明的情況(electromagnetically induced transmission)。
為理解實驗觀測，我們也以Lezama於1998年提出的理論為基礎，發展出一套能夠模擬熱銣原子氣體在不同偏振之探測光與耦合光的電磁誘發吸收效應模型。本論文將對該理論模型與上述實驗結果一併做詳細介紹與討論。

關鍵字

相位移干涉術 ； 銣原子 ； 電磁誘發吸收

並列摘要

We experimentally study the electromagnetically induced absorption (EIA) [1] in hot rubidium atoms. The EIA phenomenon has long been thought as due to coherent transfer of phase and population among the states via spontaneous decay. The typical EIA effects follow the so-called Lezama condition [2]. Nevertheless, anomalous EIA which essentially violates the Lezama criteria was also observed [3]. Chou and Evers proposed a theoretical model which could explain the anomalous EIA and predicted new effects due to quantum interference [4]. In this report, we will show our progress on experimental study and preliminary results on EIA and its anomalous effects. We will also present a theoretical model as well.

並列關鍵字

Phase shifting interferometry ； Rubidium ； Electromagnetically Induced Absorption

參考文獻

[1] A. V. Taichenachev,A. M. Tumaikin, and V. I. Yudin “Electromagnetically induced absorption in a four-state system” Phys. Rev. A 61, 011802 (1999)

[2] A. Lezama, S. Barreiro, and A. M. Akulshin “Electromagnetically induced absorption” Phys. Rev. A 59, 4732 (1998)

[3] A. Lezama, S. Barreiro, A. Lipsich, and A. M. Akulshin “Coherent two-field spectroscopy of degenerate two-level systems” Phys. Rev. A 61, 013801 (1999)

[4] 劉智遠, “相位移干涉術於銣原子報和吸收光譜量測”, 中正大學物理研究所碩士論文(2013)

[5] C. Goren, A. D. Wilson-Gordon, M. Rosenbluh, and H. Friedmann, “Electromagnetically induced absorption due to transfer of coherence and to transfer of population” Phys. Rev. A 67, 033807 (2003)