腔内电磁诱导透明与光学前驱波研究
文献类型：学位论文
| 作者 | 彭延东 |
| 学位类别 | 博士 |
| 答辩日期 | 2011 |
| 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 ; 张敬涛 |
| 关键词 | 量子相干控制 电磁诱导透明 隧穿诱导透明 光学腔 光学前驱波 多普勒效应 |
| 其他题名 | Investigation of Intracavity Electromagnetically Induced Transparency and Optical Precursors |
| 中文摘要 | 本论文主要讨论了原子系统中电磁诱导透明和半导体纳米微结构中隧穿诱导透明在光学腔线宽、光学前驱波等方面的量子相干控制，取得了如下创新性的结果： （1）提出了利用暗态间相互作用改善光学腔特性的方案。在电磁诱导透明条件下，暗态间相互作用导致超窄透明窗口出现。该透明窗口可以很好的压窄腔线宽，得到超窄腔透射谱。在合适的条件下，双暗态下超窄腔线宽可以比单暗态时小一个量级，而且改变控制场失谐可以得到不同频率的超窄透射谱线。 （2）在双量子点分子中，利用电压控制量子点间隧穿，讨论其对光学腔线宽的影响。研究结果表明，外加偏压影响频率牵引效果和光学腔线宽。调节电压可以得到可调的光学腔窄线宽，并且有效控制光学腔稳频性能，这为设计新型光电器件提供理论参考。 （3）利用非对称双量子阱中共振隧穿增强的克尔非线性从矩形长脉冲中分离出光学前驱波。由于共振隧穿，在共振频率处介质的线性吸收几乎为零，且呈现正常色散。入射脉冲通过该透明窗口，由于慢光效应，主脉冲被延迟，于是光学前驱波从入射脉冲中分离开来。更重要的是，共振隧穿增强了交叉非线性，非线性色散增强了窄透明窗口处的正常色散，更利于得到光学前驱波信号；交叉非线性的增益导致了主脉冲的增强。 （4）基于拉曼增益过程，提出了在 N 型四能级热原子系统中利用多普勒效应增强光学前驱波的方案。原子气体热运动引起色散曲线频移，考虑多普勒效应后，大失谐拉曼共振频率处的反常色散发生陡峭变化，快光效果加速的主脉冲和光学前驱波叠加，极大地增强了脉冲前沿处瞬态信号的强度。另外，我们讨论了介质温度和控制场强度对光学前驱波的影响。 |
| 英文摘要 | In this thesis, we mainly investigate the quantum coherent control of optical cavity based on electromagnetically induced transparency in atomic systems and optical precursors based on tunneling induced transparency in atom-like systems. The main innovative and important results are listed as follows: (1) A scheme for getting a tunable ultranarrow linewidth of a cavity due to an embedded four-level atomic medium with double-dark resonances is proposed. It is shown that the steep dispersion induced by double-dark resonances in the transparency window leads to the ultranarrow transmission peak. Compared with the case of a single-dark-resonance system, the linewidth can be narrowed even by one order under proper conditions. Furthermore, the position of the ultranarrow peak can be engineered by varying frequency detuning of the control fields. (2) Cavity-linewidth narrowing by means of voltage-controlled induced transparency in asymmetric double quantum dot system is theoretically investigated. The impacts of voltage on frequency pulling and cavity linewidth narrowing are discussed. The linewidth and position of the cavity transmission can be engineered by the bias voltage. The scheme may be useful in designing novel optoelectronic devices. (3) Separation of optical precursors from a square-modulated laser pulse through asymmetric double AlGaAs/GaAs quantum wells structure via resonant tunneling is discussed. Destructive interference inhibits linear absorption and a tunneling-induced transparency (TIT) window appears with normal dispersion which delays the main pulse, then optical precursors are obtained. Due to resonant tunneling, constructive interference for nonlinear susceptibility is created. The enhanced dispersion in a narrow TIT window is about one order of magnitude larger than that of the linear case. In this case, the main pulse is much delayed and the precursor signals are easier to be obtained. Moreover, the main pulse builds up due to the gain introduced by the enhanced cross-nonlinearity. (4) We put forward a scheme for enhancement of optical precursors induced by Doppler effect via far-detuning Raman process. The system we consider here is a N-type four-level atomic ensembles, working in an active Raman gain regime and at room temperature. Due to abnormal dispersion between two gain peaks induced by a control field, fast-light-induced interference between optical precursors and main pulse bring enhancement of optical transient pulse at the rising edge of the input pulse. Moreover, abnormal dispersion becomes steep due to Doppler averaging, which leads to much enhanced intensity of the transit spike. Then the transmitted intensity may reach 23 times larger than that of input pulse. Also, the dependence of optical precursors on the temperature of atomic systems and intensity of control fields are discussed. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15667]  |
| 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 | 彭延东. 腔内电磁诱导透明与光学前驱波研究[D]. 中国科学院上海光学精密机械研究所. 2011. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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