Transient and Stationary Multiwave Mixings in Highly Nonlinear Thin Materials

本课程将涉及高度非线性材料薄结构中瞬态多波混合的实验和理论研究。实验中使用的主要材料是液晶，但一些研究也将扩展到半导体材料，以进一步建立理论和观察的普遍性。在这些介质中，主要研究人员最近的理论和实验表明，许多有用的多波混频效应可以有效地发生在平稳状态和瞬态状态。提出的研究将深入研究这些效应的几个基本有趣和重要的方面，特别是在瞬态状态下。这些包括：在高度非线性薄材料中，强烈的时空自相和互相调制/移位和侧衍射所起的作用，这些作用总是伴随着有效的波混频；相位调制效应与其他几何/光学/材料参数的相互关系，如激光脉冲宽度和强度、材料响应时间和非线性（电子、热、取向、局部或扩散等）、相互作用长度、波混频角、各向异性和双折射、极化、温度等。这一研究计划将产生新的基本测量和理论形式，用于定量描述和应用指南，包括波束和图像放大器，波束组合和转向，相位共轭器和基于相干多波混频效应的自抽运振荡器等广泛的新型非线性器件。

This program will involve experimental and theoretical studies of transient multiwave mixings in thin structures of highly nonlinear materials. The principal materials to be used in the experiments are liquid crystals, but some studies will also be extended to semiconductor materials to further establish the generality of the theories and observations. In these media, recent theories and experiments by the principal investigators have demonstrated that many useful multiwave mixing effects can occur efficiently in the stationary regime as well as in the transient regimes. The proposed studies will delve into several fundamentally interesting and important aspects of these effects, especially in the transient regime. These include: the roles played by intense temporal and spatial self- and mutual-phase modulations/shifts and side diffractions that invariably accompany efficient wave mixing in highly nonlinear thin materials; the interrelationship between the phase modulation effects and other geometrical/optical/material parameters such as the laser pulse width and intensities, material response time and nonlinearity (electronic, thermal, orientational, local or diffusive, etc.) the interaction length, wave mixing angle, anisotropy and birefringence, polarization, temperature, etc. This program of research will result in new fundamental measurements and theoretical formalisms for quantitative descriptions of, and application guidelines for, a broad new class of nonlinear devices including beam and image amplifiers, beam combining and steering, phase conjugator and self-pumped oscillators, based on coherent multiple wave mixing effects.