Extremely High Nonlinear Organic Crystals

9307182张提出了一类特殊的非线性有机晶体的光学非线性的研究。首席研究人员建议将这种晶体用于高速集成电路的光电表征。这种在Ge上合成并在Rensselaer上重结晶的非线性有机晶体表现出极高的非线性。在我们所知的所有天然无外偏材料中，这些有机晶体发射出最强的光致太赫兹辐射场。提出了一种利用新发展的超快光电子技术测量有机晶体二阶非线性极化率的方案。通过分析来自这些晶体的亚皮秒光整流辐射的相位和幅度，将识别出独立的非零极化率张量元素的比率。探讨了它们在飞秒光激发后的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，用于超高速集成电路中太赫兹带宽电磁信号的非接触喷射和检测。这项拟议的工作有望对这些非线性有机晶体的物理理解产生重大影响，并有望为这些晶体的光电表征提供重要的应用。***

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. ***