Controlling Nonlinear and Quantum Dynamics in Multi-Level Coherent Media

近十年来，多层原子系统中的原子相干性和量子干涉效应引起了人们的广泛关注。在实验中已经观察到许多有趣的效应，如电磁感应透明（EIT）、光速的急剧减慢、光脉冲在原子组装中的存储以及增强的非线性光学过程。该基金支持的研究将包括与极弱激光束（单光子水平）相互作用的多层次原子系统的非线性和量子动力学效应的研究。这些研究将增加对基础物理学的基本理解，并导致新效应的发现。在实验中，诱导原子相干性将极大地改变和控制多层系统的线性和非线性光学性质。此外，这些多层原子将被放置在光学腔内，以便研究其他有趣的非线性和量子动力学现象，如控制混沌，单光子开关，量子逻辑门和量子隧道。这些基础研究将为光电器件带来新的发现和新的设计概念。在这些控制良好的实验室系统中，理解和控制非线性和量子动力学行为（如混沌、随机共振和隧道效应）可以对具有类似复杂非线性动力学行为的许多其他科学领域产生重大影响，如气候、化学、生物科学、医学科学和物理学的其他分支。研究低光强多层次相干EIT系统中的非线性和量子效应，对于开发用于量子信息处理和量子网络的单光子全光开关或量子逻辑门至关重要，并有助于未来的技术进步。本研究的另一个重要好处是培养从事现代光学实验室基础和应用研究项目的研究生和本科生。

Atomic coherence and quantum interference effects in multi-level atomic systems have attracted great attention in the past decade. Many interesting effects have been observed experimentally such as electromagnetically induced transparency (EIT), dramatic slowing of the speed of light, storage of light pulses in atomic assembles, and enhanced nonlinear optical processes. The research supported by this grant will include studies of nonlinear and quantum dynamical effects in multi-level atomic systems interacting with extremely weak laser beams (at the single-photon level). These studies will increase fundamental understanding of basic physics and lead to discoveries of novel effects. Both linear and nonlinear optical properties in multi-level systems will be greatly modified and controlled experimentally by the induced atomic coherence. Additionally these multi-level atoms will be placed inside an optical cavity so that additional interesting nonlinear and quantum dynamical phenomena can be studied, such as controlling chaos, single-photon switching, quantum logic gates, and quantum tunneling. These fundamental investigations will lead to new discoveries and novel design concepts for optoelectronic devices. Understanding and controlling nonlinear and quantum dynamical behaviors (such as chaos, stochastic resonance, and tunneling) in these well-controlled laboratory systems can have great impacts in many other areas of sciences with similar complicated nonlinear dynamical behaviors, such as climate, chemistry, biological science, medical science, and other branches of physics. Investigations of nonlinear and quantum effects in the multi-level coherent EIT systems with low light intensities will be essential in developing single-photon all-optical switching or quantum logic gates for quantum information processing and quantum networking, and contributing to future technology advances. Another important benefit in the proposed research is training graduate and undergraduate students working in the fundamental and applied research projects in modern optical laboratory.