水溶性CdTe量子点的三阶光学非线性极化特性  

The property of third-order optical nonlinear susceptibility ofwater soluble CdTe quantum dots

作　　者：吴文智[1] 郑植仁[1] 金钦汉[2] 闫玉禧[2] 刘伟龙[1] 张建平[1,3] 杨延强[1] 苏文辉[1] 

机构地区：[1]哈尔滨工业大学,凝聚态科学与技术研究中心,哈尔滨150001 [2]吉林大学,化学学院微分析仪器研究所,长春130021 [3]中国人民大学化学系,北京100872

出　　处：《物理学报》2008年第2期1177-1182,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10774034,10674034,60478015)资助的课题.~~

摘　　要：利用超短脉冲Z扫描技术和光学Kerr效应研究了以巯基丙酸为稳定剂的CdTe量子点水溶液的三阶光学非线性极化特性.在532nm,30ps和800nm,130fs脉冲激光激发下,发现分别具有正负相反取值的三阶光学非线性折射率,自由载流子吸收和双光子吸收分别是这两种脉冲激光激发下三阶光学非线性吸收的起因.测量得到CdTe量子点的三阶光学非线性极化率约为CS2的3·2倍,在520—700nm光谱区的CdTe量子点的光学响应时间小于400fs.The property of optical nonlinear susceptibility of the CdTe quantum dots （QDs） has been studied by using Z-scan and optical Kerr effect technique. Laser-induced sign reversal of the nonlinear refractive index of CdTe quantum dots appears under femtosecond and picosecond pulse excitation. Two-phonon absorption and free carrier absorption in the nanometer-sized CdTe are the possible origins of the nonlinear absorption. This material has the ultrafast response time of less than 400 fs in optical switching operation, and the peak Kerr transmittance is found to be 3.2 times greater than that of the standard CS2 liquid Kerr medium.

关 键 词：CdTe量子点(QDs) Z扫描 三阶光学非线性极化特性 双光子吸收 

分 类 号：O437[机械工程—光学工程]