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题名	量子调控小量子系统克尔非线性研究
作者	孙辉
学位类别	博士
答辩日期	2008
授予单位	中国科学院上海光学精密机械研究所
导师	龚尚庆
关键词	量子调控 克尔非线性 自相位调制 交叉相位调制 电磁诱导透明 Fano干涉 隧穿诱导透明 光孤子
其他题名	Quantum coherent control of Kerr nonlinearity in small quantum system
中文摘要	量子调控是近年来量子光学和激光物理等学科的交叉前沿研究领域。其非线性光学特性研究可以推动量子光学与激光物理等学科的发展，同时对于如量子信息科学等许多新兴与交叉学科的发展具有重要意义。将量子调控非线性光学特性研究从原子系统推广到半导体纳米微结构不仅有助于理解半导体结构中的量子相干效应，而且为基于半导体微结构中相干效应的光学器件提供理论依据。 本论文主要就多能级原子系统与半导体量子阱结构中的克尔非线性方面的量子调控进行了深入研究，并对其可能的应用进行了简单的探讨，取得了一些创新性研究成果。主要包括： 1. 研究了Tripod型四能级原子与四个激光场相互作用系统中相对相位对电磁诱导透明以及自相位调制的相干调控效应。在适当选择驱动场强度的条件下，通过对它们之间的相对相位的调控可实现弱吸收的自相位调制增强。 2. 基于电磁诱导透明探讨了四个激光场与双Lambda型原子相互作用系统中的相对相位对交叉相位调制的相干调控效应。通过对相对相位的适当调控可获得大的交叉相位调制，而线性吸收和非线性吸收可以同时完全被抑制，对该系统在相位门方面的潜在应用的可能性也进行了简单探讨。 3. 基于激发子带与连续态之间的相互作用导致的Fano干涉效应，探讨了非对称GaAs双量子阱结构中的Fano干涉对吸收与自相位调制的影响。Fano干涉引起激发态子带的Stark能级移动可导致自相位调制增强，而线性与非线性吸收可以同时被完全抑制。 4. 基于隧穿诱导透明，研究了非对称AlGaAs/GaAs双量子阱结构中共振隧穿对交叉相位调制的量子调控效应。研究结果表明该结构中共振隧穿对交叉相位调制表现为干涉增强，并结合隧穿诱导透明，可实现弱吸收的大交叉相位调制。进一步对非线性相移的计算表明该结构在低光强下的全光开关方面有潜在应用。 5. 用电子隧穿耦合替代控制场，对非对称双量子点结构中的超慢光孤子进行了探讨。研究结果表明该结构中的自克尔非线性可以平衡群速度色散导致超慢群速度的亮孤子与暗孤子产生，用偏置电压控制电子隧穿耦合强度，可以实现对光孤子群速度的有效调控。
英文摘要	Study on quantum coherent control is the cross-research area of laser physics, quantum optics and other disciplines. Further research in quantum coherent control of the nonlinear optical properties not only propel the development of these subjects but also have significant contributions to the emerge and progress of new subjects such as quantum information, uantum computation and other rising or cross disciplines. There is great interest in extending the quantum coherent control from atomic system to semiconductor nano materials, not only for the understanding of the nature of quantum coherence in semiconductors but also for the possible mplementation of optical devices based on these coherent properties. In this thesis, we mainly investigate the quantum coherent control of Kerr nonlinearity in atomic scheme and semiconductor quantum wells. The main innovative and important results are: 1. The enhancement of Kerr nonlinearity is investigated in phase-dependent double electromagnetically induced transparency (EIT) medium, in which the four levels are interacted with four laser fields. We find, in this laser-atom interacting system, that appropriate choice of the relative phase and intensities of the driven fields could lead to giant Kerr nonlinearity [self-phase modulation (SPM)], while the linear and nonlinear absorptions are very weak and can be neglected simultaneously. 2. We investigate a four-level double-Lambda atomic scheme interacting with four laser fields in a closed-loop configuration, and study the Kerr nonlinearity associated with cross phase modulation (XPM) based on EIT. By choosing the relative phase appropriately, large XPM can be achieved, while the linear and two-photon absorptions can be canceled completely. 3. The enhancement of Kerr nonlinearity (SPM) in an asymmetric double GaAs quantum well is investigated based on Fano interference, which is caused by tunneling from the excited subband to the continuum. In our structure, the ac-Stark energy shift of the excited subband could lead to the enhancement of the strength of SPM, while the linear and nonlinear absorptions can be canceled completely and simultaneously. 4. We propose an asymmetric double AlGaAs/GaAs quantum well structure with a common continuum to generate a large XPM. It is found, owing to the constructive interference in XPM induced by resonant tunneling and tunneling induced transparency (TIT), that a large XPM can be achieved with vanishing linear and two-photon absorptions. Our numerical findings show that this structure has the potential application in all-optical switching at low light level. 5. We show the formation of ultraslow bright and dark solitons in an asymmetric double quantum dots structure. In this structure, the pump field is replaced by electron-tunneling coupling. With appropriate conditions we demonstrate that the interplay between dispersion and self-Kerr nonlinearity results in the generation of ultraslow bright and dark solitons, whose group velocity can be controlled by bias voltage.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/15217]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	孙辉. 量子调控小量子系统克尔非线性研究[D]. 中国科学院上海光学精密机械研究所. 2008.

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