Research Initiation Award: Nonlinear Optical Materials Via Sol-Gel Processing

研究启动奖：通过溶胶-凝胶加工的非线性光学材料

• 批准号: 9009481
• 负责人: Joel Plawsky
• 金额: $ 7万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-06-02 至 1992-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9009481&HistoricalAwards=false
• 关键词: Research; Initiation; Award; Nonlinear; Optical

The discovery of optical second harmonic generation in crystals in 1961 spurred rapid progress in the field of nonlinear optics. Nonlinear optical materials are materials whose optical properties depend upon the intensity of light incident upon them. The nonlinearity could be in the form of an intensity dependent refractive index or a saturable absorption. These materials have practical applications in telecommunications, digital computers, and laser fusion. They have the potential to become future optical semiconductors which can operate at frequencies two to three orders of magnitude higher than current semiconductor technology. The PI plans to explore formation of commercially viable nonlinear optical materials using the sol-gel technique. The sol-gel process is a means for producing inorganic films and monolithic structures from organo-metallic monomeric compounds. The process is analogous to step reaction polymerizations in organic systems where the monomer is usually a metal alkoxide such as tetramethoxysilane. These reactions are run at room temperature, in a common solvent for alkoxide and water, and using either an acid or base catalyst. The sol-gel process will be used to produce new nonlinear optical materials by polymerizing modified alkoxide monomers of the form RSi(OR')3 where R represents an organic functionality demonstrated to have a high nonlinear susceptibility. Work will focus on R-groups which are primarily substituted benzenes, pyridines and azo dyes. Commercially available alkoxides and custom alkoxides synthesized as part of this research will be investigated. Thin film and monolithic materials will be made. To facilitate the observation of second-order nonlinear effects, the dipoles of the organic functionality will be aligned using corona poling. The second-order and third-order susceptibilities of the starting materials as well as the polymerized materials will be assessed using second harmonic generation and four-wave mixing respectively. The strength, chemical and environmental resistances, and thermal stability of the film and bulk materials will also be determined.

1961年晶体光学二次谐波的发现促进了非线性光学领域的迅速发展。非线性光学材料是一种光学性质取决于入射光强度的材料。非线性可以以强度相关折射率或饱和吸收的形式出现。这些材料在电信、数字计算机和激光聚变方面有实际应用。它们有可能成为未来的光学半导体，可以在比当前半导体技术高两到三个数量级的频率上工作。PI计划利用溶胶-凝胶技术探索商业上可行的非线性光学材料的形成。溶胶-凝胶法是一种从有机金属单体化合物中生产无机薄膜和整体结构的方法。该过程类似于有机体系中的阶跃反应聚合，其中单体通常是金属醇氧化合物，如四甲基氧基硅烷。这些反应是在室温下进行的，在醇氧化物和水的共同溶剂中，使用酸或碱催化剂。溶胶-凝胶工艺将用于通过聚合形式为RSi（OR’）3的改性醇氧单体来生产新的非线性光学材料，其中R代表具有高非线性敏感性的有机官能团。工作将集中在r基团上，主要是取代苯、吡啶和偶氮染料。作为本研究的一部分，将对市售的烷氧化物和定制的烷氧化物进行研究。薄膜和单片材料将被制造出来。为了方便观察二阶非线性效应，将利用电晕极化对有机官能团的偶极子进行排列。起始材料和聚合材料的二阶和三阶磁化率将分别用二次谐波产生和四波混频来评估。薄膜和块状材料的强度、耐化学性和环境性以及热稳定性也将被确定。