表面修饰的Ag_2S纳米微粒的光学非线性特性  

Third-Order Nonlinearities of Ag_2S Nanoparticles Capped with 2,2’-Bipyridine and Hexametaphosphate

作　　者：王刚[1] 崔一平[1] 张宇[2] 汪昕[2] 傅德刚[2] 陆祖宏[2] 

机构地区：[1]东南大学电子工程系,南京210096 [2]东南大学分子与生物分子电子学实验室,南京210096

出　　处：《光学学报》2001年第2期218-221,共4页Acta Optica Sinica

基　　金：国家自然科学基金! (6 97710 16 )

摘　　要：用胶体法制备了表面分别修饰六偏磷酸钠 (HMP)和 2 ,2’ 联吡啶 (BPy)的Ag2 S纳米微粒。通过背向简并四波混频实验装置对它们在单光子非共振区域的三阶光学非线性进行了实验研究 ,分别测量了两种Ag2 S纳米微粒在它们超滤液中三阶非线性极化率 χ( 3 ) 随浓度的变化 ,并拟合得到了两种纳米微粒的三阶非线性极化率。实验结果表明 ,双光子共振增强是实验中非线性极化的主要过程 。Two kinds of Ag 2S nanoparticles with different surface capping molecules (2,2’ bipyridine and hexametaphosphate ) were prepared by colloidal chemical method. Their third order nonlinear optical properties have been studied in non resonance region of one photon via degenerate four wave mixing in phase conjugation geometry. The results show that two photon resonant process greatly contributes to the third order nonlinearities of Ag 2S nanoparticles. It is also found that the third-order susceptibicities χ (3)  are intensively subjected to the surface capping molecules. This phenomenon is interpreted in terms of local field enhancement effect related to refractive index of the media around nanoparticles.

关 键 词：简并四波混频 三阶非线性电极化率 纳米微粒 非共振非线性 双光子吸收 局域场效应 硫化银 表面修饰 AG2S 

分 类 号：TB383[一般工业技术—材料科学与工程] O437[机械工程—光学工程]