Extremely High Nonlinear Organic Crystals

9307182研究了一类特殊的非线性有机晶体的光学非线性。 首席研究员建议使用这种晶体的光电表征的高速集成电路。 这种在GE合成并在Rensselaer重结晶的非线性有机晶体显示出极高的非线性。 这些有机晶体在我们所知的所有天然非外部偏置材料中发出最强烈的光诱导太赫兹辐射场。 提出了利用超快光电技术测量有机晶体二阶非线性极化率的方案。 通过分析这些晶体的亚皮秒光整流辐射的相位和振幅，将确定独立的非零磁化率张量元素的比例。 探讨了飞秒光激发后，它们在光整流过程中产生太赫兹持续振荡的物理根源。 这种有机晶体将被集成到电光采样系统中，用于非接触式喷射和高速集成电路中太赫兹带宽电磁信号的检测。 拟议的工作预计将有实质性的影响，这些非线性有机晶体的物理理解，也有望提供重要的应用，这将确保这些晶体的光电特性。 ***

9307182 Zhang A study of optical nonlinearities of an unusual class of nonlinear organic crystals is proposed. The principal investigator proposes to use this crystal for optoelectronic characterization of high- speed integrated circuits. This nonlinear organic crystal, which is synthesized at GE and recrystallized at Rensselaer, shows extremely high nonlinearity. These organic crystals emit the most intense optically induced terahertz radiated field among all of the natural non-externally biased materials we know. A plan to measure the second order nonlinear susceptibility of these organic crystals by using a newly developed ultrafast optoelectronic technique is proposed. The ratio of independent nonvanishing susceptibility tensor elements by analyzing the phase and the amplitude of subpicosecond optical rectification radiation from these crystals will be identified. The physics origin of THz persistent oscillation in their optical rectification after femtosecond optical excitation will be explored. This organic crystal will be integrated into an electro-optic sampling system for noncontact ejection and detection of terahertz bandwidth electromagnetic signals in ultrahigh speed integrated circuits. The proposed work is expected to have a substantial impact on the physical understanding of these nonlinear organic crystals and is also expected to provide important applications which will ensue for the optoelectronic characterization of these crystals. ***