Optical Nonlinearities Enhanced by Near-Field Diffraction in Artificial Dielectric Nanostructures

9912476范曼鉴于高带宽光纤所提供的通信容量的巨大增加，很快就需要新技术来提供超高带宽交换和网络功能。光纤中的可用带宽目前主要利用波长和时分复用技术，这两种技术都越来越依赖于利用直接有效的非线性光相互作用来产生、检测、切换、复用和解复用光信息携带波的能力。使用现有非线性光学材料和器件的这些技术的能力和应用的增长受到效率的限制（由于相对较小的有效非线性系数和由减相施加的短有效相互作用长度）。本提案的目标是在人工纳米结构中利用近场相互作用进行有效的光学非线性发展的基础研究。拟议的办法将集中于：(i)通过工程纳米结构来增强光学非线性，表现出局部场的集中；（ii）结合光学非线性增强，因为超短激光脉冲可以实现非常高的场效应；（iii）工程宽带相位匹配的纳米和微观结构，以满足光电和成像系统的需要（例如，利用光子晶体的独特特性，允许在宽角度和波长范围内工作）。本提案的具体目标包括这些新型非线性光学纳米结构的严格建模，设计，制造和表征。还将特别强调我们的最终目标，即使用这些增强的光学非线性来构建功能性中光器件和组件，这些器件和组件将对光通信网络（例如波长转换器，时空和时空解复用器，开关等）和成像系统（例如生物医学成像的时间门控）产生重大影响。以及额外的新应用（例如高阶谐波产生用于高分辨率光学光刻）。本文的研究成果不仅将对光通信网络和成像系统的全光非线性处理器的发展产生重大影响，而且还将为研究中尺度光学体系结构中近场非线性光学效应提供基础技术。这些研究还将促进近场非线性介质纳米结构中的矢量光波衍射、纳米结构材料中非线性光学过程的理解以及使用沉积和离子注入技术制造此类器件等领域的基础科学和工程。该项目也将在研究生和本科阶段的科学和工程人力资源的教育和发展中发挥独特的作用，正如我们之前在NSF的支持下（在期刊和会议上发表了100多篇论文，完成了6个博士学位和5个硕士学位，NSF REU为8名本科生，目前指导10名博士生）。***

9912476FainmanGiven the enormous increase in communication capacity provided by high bandwidth optical fibers, new technologies will soon be necessary to provide ultra-high bandwidth switching and networking capabilities. The bandwidth available in optical fibers is currently exploited using wavelength and time division multiplexing techniques, both of which increasingly rely on the ability to generate, detect, switch, multiplex and demultiplex optical information-carrying waves using direct efficient nonlinear optical interactions. Growth in the capabilities and applications of these technologies using existing nonlinear optical materials and devices is limited by efficiency (due to the relatively small effective nonlinear coefficients and the short effective interaction lengths imposed by dephasing).The goal of this proposal is to conduct basic research towards the development of efficient optical nonlinearities exploiting the near field interactions in artificial nanostructures. The proposed approach will focus on: (i) enhancement of optical nonlinearities by engineering nanostructures that exhibit local-field concentration, (ii) incorporation of the optical nonlinearity enhancement due to the very high field effects achievable with ultrashort laser pulses, and (iii) engineering broadband phase-matching nano- and micro-structures to meet the needs of optoelectronic and imaging systems (e.g., using the unique properties of photonic crystals to allow operation in broad angular and wavelength bands). The specific objectives of this proposal include rigorous modeling, design, fabrication and characterization of these novel nonlinear optical nanostructures. Special emphasis will also be given to our ultimate objective of using these enhanced optical nonlinearities to build functional meso-optic devices and components that will have a significant impact on optical communication networks (e.g. wavelength converters, space-to-time and time-to-space demultiplexers, switches, etc.) and imaging systems (e.g. time-gating for biomedical imaging), as well as on additional novel applications (e.g. higher order harmonic generation for high-resolution optical lithography).The proposed research will not only have a significant impact on the development of all-optical nonlinear processors for optical communication networks and imaging systems, but also result in development of the basic technology for studying the near field nonlinear optical effects in meso-scale optical architectures. The proposed studies will also advance the basic science and engineering in such areas as vector optical wave diffraction in near-field nonlinear dielectric nanostructures, understanding of nonlinear optical processes in nanostructured materials, and fabrication of such devices using deposition and ion implantation techniques. The proposed project will also play a unique role in the education and development of human resources in science and engineering at the graduate and undergraduate levels, as under our prior NSF support (contributing to over 100 manuscripts in refereed journals and conference presentations, the completion of 6 Ph.D. and 5 M.Sc. degrees, NSF REU for 8 undergraduate students, and the current supervision of 10 Ph.D. students).***