新型偶氮苯衍生物的三阶非线性光学特性  

Third-order nonlinear optical properties of an azobenzene derivate

作　　者：李梦梦[1] 朱宝华[1] 冉霞[1] 刘波[1] 郭立俊[1] 

机构地区：[1]河南大学光生物物理研究所,物理与电子学院,开封475004

出　　处：《物理学报》2016年第2期142-147,共6页Acta Physica Sinica

摘　　要：本文以30 ps的脉冲激光为激发光源,用Z扫描技术研究了偶氮苯类材料4-羟基-4’-羧基偶氮苯(BN)和N-(3,4,5-辛氧基苯基)-N’-4-[(4-羟基苯)偶氮苯]1,3,4-恶二唑(AOB-t8)及金属复合物(Au/AOB-t8)的三阶非线性光学性质,并从理论上进行了分析和计算.结果表明,AOB-t8的三阶非线性极化率是BN的1.38倍,其非线性光学效应的增大是由共轭链增长、大π键增多引起的.结果同时给出,AOB-t8的三阶非线性极化率是其与金纳米颗粒复合物的4.7倍,这种与金属复合产生的非线性光学效应的减弱是金属引入的局域场效应与有机分子大π键作用之间相互抵消导致的.In recent years, azobenzene derivates have received much attention for their potential application in optical data storage, biophotonics, holographic memories and waveguide switches optical sensors, and sensitive optical components from laser damage in both civilian and military applications. Experimental and theoretical studies demonstrate clearly the effect of the sonor-pi-acceptor （D-π-A） conjugation on the steady-state and time-resolved PL spectra of azobenzene derivate films in multifarious situations, but comparatively little is concerned about the two-photon absorption and re- fraction involved in a single benzene ring. Furthermore, the excitation laser source on the azobenzene derivates in some investigations is continuum laser or nanosecond pulsed laser, where it is hard to avoid thermal effect on nonlinear optical （NLO） process produced by these lasers. To explore the origin of the azobenzene derivates＇ D-π-A conjugation-dependent NLO process is a challenging task and has great signicance in describing the molecular structures of these azobenzene nanostructures as well as improving the performance of azobenzene derivates＇ devices. The D-π-A conjugation of azoben- zene functional material can be modified by mixing the azobenzene derivates with metal nanoparticles, so it is convenient to study how the D-π-A conjugation affects the NLO properties by using the azobenzene derivate-metal composites. In this letter, the D-π-A conjugation-dependent NLO absorption and refraction of the two kinds of azobenzene derivates 4-（（4＇-hydroxybenzene） azo） benzyl acid （BN） and N-（3, 4, 5-octanoxyphnyl）-N＇-4-[（4-hydroxypheny1） azopheny1]1, 3, 4-oxadiazole （AOB-t8） are investigated by Z-scan technology using 32 ps laser pulse width at 532 nm. The azobenzene derivates＇ surface is modified using the D-π-A conjugation control and overcoating Au nanoparticles on the azobenzene derivates; and the Au/AOB-t8 composites, BN and AOB-t8 are characterized by Z-scans and absorption/fluo

关 键 词：偶氮苯衍生物 三阶非线性 表面等离子体共振 局域场 

分 类 号：O437[机械工程—光学工程]