New Methods of the Measurement of Electro-Optic Constants in Organic Materials

本研究的目的是发展一种新的测定电光常数和相关非线性光学系数的方法，并探索可用于电光和非线性光学器件的有机材料。制备了一个法布里-珀罗（FP）腔样品用于测量。在没有起偏器和检偏器对的情况下，使用纵向方案测量探测光的透射率变化。由于薄铝电极也被用作FP腔的反射镜，因此可以以极高的灵敏度检测由于吸收变化或反射率变化引起的透射率变化，其灵敏度低至10 Ω<-6>。除了这些优点之外，低电压（5-10 V）对于这种薄膜样品是足够的。本文提出了一种利用马赫-曾德尔干涉仪的新方法。这种方法可以更清楚地分离EO常数的真实的实部和虚部。为了提高干涉仪的信噪比，实现宽波段电光信号的检测，研制了一种反馈稳定系统，并测量了掺4-二乙氨基-4 '-硝基二苯乙烯（DEANS）的聚碳酸酯薄膜、聚丁二炔（PDA-3BCMU）薄膜和其它有机材料（包括几种聚合物）的电光常数。测量了掺杂在聚合物中的半导体微晶的光致发光电调制谱。

Purposes of this research are the development of a new method for the determination of the electro-optic (EO) constants and relevant nonlinear susceptibilities and the investigation of the useful organic materials which can be used the EO and nonlinear optical devices.A new convenient method is developed for the determination of the EO constants. A sample of Fabry-Perot (EP) cavity is prepared for the measurement, Without a polarizer and analyzer pair, transmittance change of probe light is measured using a longitudinal scheme, Since the thin aluminum electrodes are also used as mirrors of the FP cavity, the transmittance change due to either absorption change or eflactive index change can be detected with extremely high sensitivity down to 10^<-6>, In addition to these merits, low applied voltage (5-10 V) is sufficient for this thin film samples. The obtained signals are processed and analyzed by a microcomputer.Another new method using a Mach-Zehnder Interferometer is developed. The real and imaginary parts of the EO constants can be more clearly separated by this method. A feed-back system for the stabilization of the Interferometer is developed to improve signal to noise ratio and detect the EO signal at wide wavelength region.The EO constants of a thin film of polycarbonate doped with 4-diethylamino-4'-nitrostilbene (DEANS), a polydiacetylene (PDA-3BCMU) film, and other organic materials including several polymers are measured. The electromoduration spectrum of photoluminescence in semiconductor microcrystallites doped in polymer are also measured.