【摘要】 <正> 二阶非线性光学聚合物是最有希望实现在电光器件方面应用的材料之一.该类材料的非线性光学系数很高,响应速度快,与半导体材料的相容性较好,且比有机和无机晶体的制备更方便.目前所用的电光调制器多为光传输型,高光学活性的极化聚合物一般光学损耗较大,尤其是其吸收波段更大,使得调制器只能在其透明波段内使用,否则,传输型波导器件由于这种损耗将无法使用.而空间更多还原

【Abstract】 A novel cross-linked polyurethane with high second-order nonlinear optical(NLO) activity and high thermal stability was synthesized from disperse Red-19 and the trimer of 2,4-toluene diisocyanate. The electro-optical coefficient(r33) of the polyurethane and the electro-optical modulation efficiency of the spatial modulator were measured at lasers of 632, 650, 832 and 980 nm by the improved attenuated-total-reflection technology after the polyurethane was poled and cured. The results indicate that r33 and the modulation efficiency increase in the absorption region of the polyurethane with the descending of the incident laser wavelength. Further theoretical and experimental researches show that the enhancement of the electro-optical effect is resulted from the complex refractive index change. The change increased with the ab-sorbance of the polyurethane due to the resonance of the NLO polyurethane and the incident laser. As a result, for spatial electro-optical(EO) modulator like attenuated-total-reflection EO modulator, the absorption region can be effectively utilized notonly because the effective optical path length is much shorter that of a waveguide EO modulator and optical losses do not present a serious problem but also because the electro-optical effect will be strengthened by the resonance.更多还原