Transient Reorientation of a Doped Liquid Crystal System under a Short Laser Pulse  

作　　者：李涛 项颖 刘忆锟 王坚 杨顺林 

机构地区：[1]College of Chemistry and Life Science, China Three Gorges University, Yichang 443002 [2]School of Information Engineering, Guangdong University of Technology, Guangzhou 510006 [3]Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, PO Box 912, Beijing 100083 [4]State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275 [5]South China Institute of Environmental Science, MEP, Guangzhou 510006 [6]Success Electronics Co. Ltd., Shenzhen 518132

出　　处：《Chinese Physics Letters》2009年第8期223-226,共4页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China under Grant No 10674033, the Natural Science Foundation of Guangdong Province （8151009001000055）, and the Science and Technology Program of Guangdong Province （2007B010600060）.

摘　　要：The transient optical nonlinearity of a nematic liquid crystal doped with azo-dye DR19 is examined. The optical reorientation threshold of a 25-μm-thick planar-aligned sample of 5CB using a 50 ns pulse duration 532nm YAG laser pulse is observed to decrease from 800 mJ/mm^2 to 0.6 mJ/mm^2 after the addition of i vol% azo dopant, a reduction of three orders of magnitude. When using a laser pulse duration of 10ns, no such effect is observed. Experimental results indicate that the azo dopant molecules undergo photoisomerization from trans-isomer to cis-isomer under exposure to light, and this conformation change reorients the 5CB molecules via intermolecular coupling between guest and host. This guest-host coupling also affects the azo photoisomerization process.The transient optical nonlinearity of a nematic liquid crystal doped with azo-dye DR19 is examined. The optical reorientation threshold of a 25-μm-thick planar-aligned sample of 5CB using a 50 ns pulse duration 532nm YAG laser pulse is observed to decrease from 800 mJ/mm^2 to 0.6 mJ/mm^2 after the addition of i vol% azo dopant, a reduction of three orders of magnitude. When using a laser pulse duration of 10ns, no such effect is observed. Experimental results indicate that the azo dopant molecules undergo photoisomerization from trans-isomer to cis-isomer under exposure to light, and this conformation change reorients the 5CB molecules via intermolecular coupling between guest and host. This guest-host coupling also affects the azo photoisomerization process.

关 键 词：sea surface nonliear interaction numerical method 

分 类 号：O437[机械工程—光学工程] TN201[理学—光学]