【作者】 张多；

【导师】 吴颖；

【作者基本信息】 华中科技大学 ， 光学， 2013， 博士

【摘要】 量子相干和干涉效应能够使介质的光学特性发生显著的改变，可以用来调控光的吸收、色散、自发辐射以及非线性效应，在激光物理、量子光学、非线性光学、量子信息等诸多领域有着重要的应用。本论文研究了量子相干介质中自发辐射的相干调控和光学双稳态的实现，主要工作包括以下几个方面：1、研究了单带各向同性的光子晶体中五能级原子系统的自发辐射性质。讨论了光子带隙、Rabi频率、外场失谐量以及原子初态布居对自发辐射的影响。结果表明：自发辐射谱非常敏感地依赖于跃迁频率与光子晶体带隙的相对位置，同时自发辐射可以通过适当地调节外部泵浦场和控制场来有效控制。在自发辐射谱中能够观察到一些有趣的现象诸如谱线变窄、谱线增强、谱线抑制以及暗线的出现和多峰结构。这为我们在光子晶体中控制原子的自发辐射提供了一些有利的指导。2、研究了位于各项异性的光子晶体中的四能级原子系统的自发辐射行为。讨论了自由空间和光子带隙库中原子跃迁频率与能带边缘的相对位置、微波场的Rabi频率和失谐量对原子自发辐射性质的影响。3、研究了自由空间中用一个椭圆偏振控制光和一个外磁场控制的双三脚架型五能级冷原子系统的自发辐射性质。利用波函数方法推导出自发辐射谱的分析表达式，结果表明通过调整合适的参数如椭圆极化控制场的左旋和右旋极化部分的相位差、外磁场强度和椭圆极化控制场的Rabi频率，我们可以有效地控制原子的自发辐射特性。这些研究为原子自发辐射的调控提供了更多的自由度。4、利用一个不同程度极化的椭圆偏振光来耦合金刚石氮空位中心，从而研究其在光控制下的零声子线自发辐射特性。研究表明谱线增强、谱线变窄、谱线抑制和零声子线的自发辐射猝灭可以通过调节极化依赖的相位、塞曼移动（外磁场强度）及控制场强度来实现。并在控制场的缀饰态绘景中定性地分析了产生这些结果的物理机制。5、理论上研究了在单向环形腔中被一个椭圆极化控制光和线性极化探测光驱动的三脚架型四能级原子系统的光学双稳态行为。我们讨论了探测场的失谐量、控制场的强度、控制场两极化部分之间的相差以及原子合作参数对光学双稳态的影响。6、研究了在充有金刚石氮空位中心的光学环型腔中实现激光极化依赖和磁场控制的光学双稳态。光学双稳态的曲线能够通过新的物理参量即外磁场的强度和控制场的极化来有效的调控，这与先前的研究有所不同。同时详细讨论了控制场的强度、频率失谐量和合作参数对光学双稳态的影响。研究结果对实现全光双稳转换或编码有一定的参考价值。总之，本论文的研究加深了人们对相干介质中自发辐射的量子调控的认识和理解，也为实验上研究光学双稳态提供了一定的理论依据。这些研究对光学通讯、新型光电子器件的制作，以及全光开光和量子编码也有一定的参考价值。更多还原

【Abstract】 Quantum coherence and interference can change optical properties of the me-dia greatly, and can be used to manipulate and control absorption, dispersion, spon-taneous emission and nonlinear optical effect efficiently, as well as have manyapplications in laser physics, quantum optics, nonlinear optics and quantum infor-mation. In this thesis, we study mainly the quantum manipulation of spontaneousemission and the realization of optical bistability (OB) in coherent media. Themain content is as follows:1. we have theoretically investigated the spontaneous emission spectra of afive-level atom embedded in the photonic crystals (PCs). The influence of the rel-ative position between the transition frequency and the photonic-band-gap (PBG)edge, the detunings and Rabi frequencies of two external driving fields and initialstates of the atomic system on the spontaneous emission spectra are discussed. Itis shown that the spontaneous emission spectra are sensitively dependent on therelative position of the transition frequency to the PBG, and the spontaneous emis-sion can be controlled effectively by appropriately adjusting the external pump andcontrol fields. A few interesting phenomena can be observed in the spontaneousemission spectra, such as spectral-line narrowing, spectral-line enhancement andspectra-line suppression, as well as the appearance of dark lines and multi-peakstructures under certain conditions. This gives us a helpful clue to control thespontaneous emission of an atom in PCs.2. The spontaneous emission properties of a microwave-field-driven four-level atom embedded in anisotropic double-band PCs are investigated. The influ-ences of the band-edge positions, Rabi frequency and detuning of the microwavefield on the emission spectrum are discussed. 3. We have theoretically investigated the spontaneous emission spectra ofa cold double tripod-type five-level atom controlled by an elliptically polarizedfield and an external magnetic field in free space. A wave function approach isused to derive explicit and analytical expressions of atomic spontaneous emissionspectra. The results clearly show that, by choosing appropriate parameters of thecoupled system, such as the intensity of external magnetic field, Rabi frequencyof elliptically polarized control field and the initial probability amplitudes, we canmanipulate the spontaneous emission effectively. These investigations may providemore degrees of freedom to manipulate the atomic spontaneous emission.4. We investigate spontaneous emission properties and control of the zerophonon line (ZPL) from a diamond nitrogen-vacancy (NV) center coherentlydriven by a single elliptically polarized control field. The numerical results showthat a few interesting phenomena such as enhancement, narrowing, suppression,and quenching of the ZPL spontaneous emission can be realized by modulatingthe polarization-dependent phase, the Zeeman shift and the intensity of the controlfield in our system. In the dressed-state picture of the control field, we qualitativelyexplain these results from viewpoint of physics5. We have theoretically investigated the OB behaviors in a tripod-type four-level atomic system driven by an elliptically polarized control field and a linearlypolarized probe field inside the unidirectional ring cavity. We discuss the effectsof the frequency detuning of the probe field, the control field intensity, the relativephase between two electric field components of the control field and the coopera-tion parameter on the behavior of OB.6. We explore laser-polarization-dependent and magnetically controlled OBin an optical ring cavity filled with diamond nitrogen-vacancy (NV) defect centersunder optical excitation. The shape of the OB curve can be significantly modifiedin a new operating regime from the previously studied OB case, i.e., by adjusting the intensity of the external magnetic field and the polarization of the control beam.The influences of the intensity of the control beam, the frequency detuning, andthe cooperation parameter on the OB behavior are also discussed in details. Theseresults are useful in real experiments for realizing an all-optical bistate switchingor coding element.In conclusion, this thesis not only deepens our awareness and understandingof spontaneous emission in quantum coherent media, but also provides thetheoretical foundation for investigating OB in experiment. These investigationsmay have some reference value for optical communications and the fabrication ofnovel optoelectronic devices, as well as all-optical switching and quantum coding.更多还原