本論文包含兩個主題。第一部分研究無旋轉波近似下幾種原子與光的相互作用。第二部分研究駐波場耦合的電磁自感透明系統的反射和透射。它們的簡介如下。 / 第一部分。旋轉波近似即忽略掉原子與光相互作用哈密頓量中的反旋轉波項。它的有效性來自於能量守恆定律。但是在時間尺度非常小的情況下，根據海森堡不確定性原理，能量的不確定性可以很大，所以旋轉波近似不能應用于短時間行為的研究，比如量子芝諾和反芝諾效應，蘭姆位移，非共振極化以及超輻射和亞輻射中的能移。為超越旋轉波近似，我們對哈密頓量採用了么正變換。在變換之後的基矢之間，只有由帶修正係數的旋轉波項造成的躍遷。 / 我們從原子和真空的相互作用開始。對於氫原子來說，自由真空中沒有量子反芝諾效應，但是如果對真空態密度用腔或特異性材料做一些調製，量子反芝諾效應就會出現，蘭姆位移也會改變。我們接著研究原子和非真空光場的相互作用。我們計算了滿足光學定理的兩能級原子極化率。然後我們把么正變換用到了兩個全同原子和真空的相互作用，並計算了超輻射和亞輻射的輻射譜以及量子芝諾和反芝諾效應。 / 第二部分。在電磁自感透明系統裏，如果耦合光場為駐波，介質的極化率就會受到週期性調製而形成一維光子晶體。和傳統的傳輸矩陣不同的是，我們採用了麥克斯韋-劉維爾耦合波方程來處理這個系統並得到了光子晶體能帶的一個新的評判標準。起關鍵作用的物理量為非線性耦合係數除以波矢錯差和線性極化率的和，也就是非線性因素除以線性因素。 / 首先，我們研究了光子能帶的位置和寬度與實驗參數的量化關係。然後我們研究了溫度升高时光子晶體的融化以及向多普勒無關的多波混頻的轉化。如果在兩束對向傳播的耦合場之間引入失諧，駐波場的包絡會形成一個“飛行“的光子晶體。因為多普勒效應，順著飛行方向或者逆著飛行方向的探測光在一維光子晶體的坐標系裏具有不同的頻率。在靜止坐標系看，透射譜會在頻率上錯開並形成光學二極體。 / This thesis includes two topics. Part 1 is on the various atom-photon interactions without rotating-wave approximation (RWA). Part 2 is on the reflection and transmission in a standing wave coupled electromagnetically induced transparency (EIT) system. / Part 1. In the RWA, the counter-rotating terms in the atom-photon interaction Hamiltonian are neglected. Its validity is the result of energy conservation. However, if the time scale is sufficiently small, the uncertainly in the energy can become large, according to the Heisenberg uncertainty principle. Thus the RWA can not be applied in the study of the short time behavior, such as the quantum Zeno effect (QZE) and anti-Zeno effect (QAZE), the Lamb shift, the non-resonant polarizability and shifts in the superradiance and subradiance. To go beyond RWA, we apply a unitary transformation on the Hamiltonian. In the transformed basis, there are only secular transitions due to rotating terms with modified coupling constants. / We start from the interactions between atom and vacuum. For the hydrogen atom, there is no QAZE in free vacuum. However, with the modification in the density of states of the vacuum by a cavity or a meta-material, the QAZE appears and the Lamb shift changes. We then turn to the atom in light field, where the polarizability of a two-level atom is calculated and the results satisfy the optical theorem. The unitary transformation is then applied to two identical atoms interacting with vacuum. Their various emission spectra of the superradiance and subradiance and the QZE and QAZE are studied. / Part 2. In an EIT system, if the coupling field is a standing wave, the susceptibility of the medium is periodically modified to form a one-dimensional photonic crystal (1DPC). In contrast to the conventional treatment with transfer matrix, we use Maxwell-Liouville coupled-wave equations and propose new criteria for the bandgap of the photonic crystal (PC). The relevant quantity is the ratio between the nonlinear coupling coefficient and the wave vector mismatch plus the linear susceptibility, which is the nonlinear effect over the linear effect. / First, we study the quantitative relation between the position and width of the photonic bandgap and the experimental parameters. We then show that, as the temperature rises, the 1DPC melts down and enters the Doppler-free wave-mixing regime. By introducing detuning between the two counter-propagating fields in the standing wave, we make the envelope of the standing wave move and form a ‘flying’ 1DPC. Owing to the Doppler Effect, the probe fields propagating along with or counter to the moving direction have different frequencies in the 1DPC frame. In the rest frame, the transmission spectra in two directions are thus shifted with respect to each other and we obtain an optical diode. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Wang, Dawei = 無旋轉波近似下原子-光子相互作用和駐波耦合的電磁自感透明系統 / 王大偉. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 128-135). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Wang, Dawei = Wu xuan zhuan bo jin si xia yuan zi-guang zi xiang hu zuo yong he zhu bo ou he de dian ci zi gan tou ming xi tong / Wang Dawei. / Abstract --- p.iv / Acknowledgements --- p.vii / Table of Contents --- p.xi / List of Figures --- p.xiii / Chapter Part 1 --- Atom-photon interactions without rotating-wave approximation --- p.1 / Chapter Chapter 1 --- Introduction on atom-photon interactions --- p.2 / Chapter 1.1 --- Spontaneous emission --- p.2 / Chapter 1.2 --- Quantum Zeno and anti-Zeno effect --- p.8 / Chapter 1.3 --- Rotating-wave approximation --- p.10 / Chapter 1.4 --- Go beyond the rotating-wave approximation --- p.12 / Chapter 1.5 --- Non-dynamic Lamb shift --- p.15 / Chapter 1.6 --- Summary --- p.17 / Chapter Chapter 2 --- QZE, QAZE and Lamb shift in vacuum --- p.18 / Chapter 2.1 --- Introduction --- p.18 / Chapter 2.2 --- QZE in the free vacuum --- p.19 / Chapter 2.3 --- QAZE in modified vacuum --- p.21 / Chapter 2.4 --- Time Evolution of the Lamb Shift --- p.25 / Chapter 2.5 --- The Lamb shift in modified vacuum --- p.30 / Chapter 2.6 --- Summary --- p.35 / Chapter Chapter 3 --- Atom in light: polarizability and scattering --- p.37 / Chapter 3.1 --- Introduction --- p.37 / Chapter 3.2 --- The polarizability of a two-level atom without RWA --- p.39 / Chapter 3.3 --- The optical theorem --- p.43 / Chapter 3.4 --- The effects of the counter rotating terms --- p.46 / Chapter 3.5 --- The frequency shift --- p.48 / Chapter 3.6 --- Summary --- p.50 / Chapter Chapter 4 --- Spontaneous emission of two identicalatoms --- p.51 / Chapter 4.1 --- Introduction --- p.51 / Chapter 4.2 --- Unitary transform of the Hamiltonian --- p.52 / Chapter 4.3 --- Dynamicevolution --- p.57 / Chapter 4.4 --- Decay rates, Lamb shift and emission spectrum in the longtime limit --- p.59 / Chapter a) --- The decayrates --- p.59 / Chapter b) --- The Lamb shift --- p.60 / Chapter c) --- The emission spectra --- p.62 / Chapter 4.5 --- Short time evolution --- p.68 / Chapter 4.6 --- Summary --- p.70 / Chapter Appendix --- the shifts and decay rates of the symmetric and anti-symmetric states --- p.71 / Chapter Part 2 --- Standing wave coupled electromagnetically induced transparency system --- p.74 / Chapter Chapter 5 --- Introduction on electromagnetically induced transparency --- p.75 / Chapter 5.1 --- The electromagnetically induced transparency --- p.75 / Chapter 5.2 --- The susceptibilities of SWEIT --- p.81 / Chapter 5.3 --- Summary --- p.86 / Chapter Appendix --- the recursion relation and the proof of Eq.(212) --- p.86 / Chapter Chapter 6 --- From photonic crystal to Doppler-free wave-mixing --- p.90 / Chapter 6.1 --- Introduction --- p.90 / Chapter 6.2 --- The Maxwell-Liouville equations --- p.91 / Chapter 6.3 --- The photonic bandgaps --- p.93 / Chapter 6.4 --- The meltdown of the photonic crystal and the pulse matching --- p.99 / Chapter 6.5 --- Summary --- p.106 / Chapter Appendix A --- the Maxwell-Liouville equation --- p.106 / Chapter Appendix B --- a new criterion of photonic band-gaps --- p.109 / Chapter Chapter 7 --- The optical-diode by a flying photonic crystal --- p.112 / Chapter 7.1 --- Introduction --- p.112 / Chapter 7.2 --- Coupled-wave equations of the ‘flying’ photonic crystal --- p.113 / Chapter 7.3 --- The spectra of the optical diode --- p.118 / Chapter 7.4 --- The influence of the experimental parameters --- p.120 / Chapter 7.5 --- Summary --- p.126 / CURRICULUM VITAE --- p.136
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_328150 |
| Date | January 2012 |
| Contributors | Wang, Dawei , 1984-, Chinese University of Hong Kong Graduate School. Division of Physics. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, bibliography |
| Format | electronic resource, electronic resource, remote, 1 online resource (xvi, 137 leaves) : ill. (chiefly col.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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