群速度调控与反直觉色散现象研究

The control of group velocity is always one of the basic issues in the study of pulse propagation in photonic devices. By controlling the dispersion relations of photonic devices, a variety of fast-light and slow-light phenomena have been realized. How to use a single system for the tunable manipulation from superluminal to subluminal group velocities has attracted great attention. Recently we have discovered the counterintuitive dispersion effect in the slab (or cavity) containing the active atoms, however, there remain the related controversial issues yet to be resolved. We are going to explore the coupling systems which consist of a cavity (a single slab or multi-layered structures) doped with various types of atoms, by taking into account the feedback mechanism from the interfaces of the structures, in order to find the new physical mechanisms of manipulating the group velocities flexibly. We will plan to figure out the universal features of various types of light pulses propagating through the fast- and slow-light photonic devices and the corresponding metric methods. Furthermore, we will try to resolve the dispute on counterintuitive dispersion phenomenon, and further explore its physical origin. Through our efforts on both theoretical and numerical methods, we try to obtain (or design) the photonic devices with the broadband abnormal dispersion and give a deep insight on the physical meaning of fast- and slow-light effects. Our study will be helpful and valuable in the application of designing new photonic devices and be significant in the application of full-optical information processing.

群速度调控一直是研究脉冲信号在光子器件中传播的基本问题之一。通过控制光子器件的色散关系，人们可以实现各类快光和慢光现象。同时如何利用单个系统实现灵活的群速度快光与慢光的操控也是该领域研究的热点之一。最近我们发现在平板或腔内掺杂增益原子可实现反直觉色散关系，但与之相关的争议问题尚有待解决。本项目拟从构建掺杂不同原子与腔（平板或多层介质）耦合系统出发，考虑到结构界面的反馈机制，寻找灵活调控群速度的新物理机制；分析各类脉冲信号在快光与慢光光子器件中的普适特点及度量方法；解决有关反直觉色散现象争议，进一步探究反直觉色散现象的物理根源。我们希望通过理论分析和数值模拟等多方面研究，结合电磁波、激光物理和量子光学的理论方法，研究新型色散关系，设计或获得具有宽带反常色散的光子器件，以便深层次理解群速度快光、慢光的物理意义。该项目的研究将对设计新型光子器件及丰富全光信息处理有极具重要的意义。

脉冲群速度一直是研究脉冲信号在光子器件中传播的最基本的物理量之一,为提高光子器件的信息处理能力，调控群速度是最基本的手段之一。通过控制光子器件的色散关系，人们可以实现各类快光和慢光现象；同时如何利用单个系统实现灵活的群速度快光与慢光的操控也是该领域研究的热点之一。本项目结合电磁波、激光物理和量子光学的理论与实验方法，研究新型色散关系。通过本项目的研究,我们发现在平板或腔内掺杂增益原子可实现反直觉色散关系，考虑了光脉冲在不同色散体系中的群速度调控现象。实验上分析了各类脉冲信号在快光与慢光光子器件中用保真度度量的普适性；进一步探究了奥托结构的表面等离子共振处发现存在反直觉的色散效应，以及在含单层石墨烯的多层结构中太赫兹频率区域的光脉冲反射在表面等离子共振处实现可调群速度控制。研究了四能级多普勒展宽原子体系中的光脉冲慢光与快光传输行为。与此同时，我们还在研究经费的资助下，建立了产生光场调控的光学实验平台，研究了新型结构光场的传输和新型光学材料的光谱特性。该项目的研究有利于人们设计或获得具有宽带反常色散的光子器件、以便深层次理解群速度快光、慢光的物理意义；同时对设计新型光子器件及丰富全光信息处理有极具重要的意义。