Transient Reorientation of a Doped Liquid Crystal System under a Short Laser Pulse
LI Tao1, XIANG Ying2,3, LIU Yi-Kun4, WANG Jian5, YANG Shun-Lin6
1College of Chemistry and Life Science, China Three Gorges University, Yichang 4430022School of Information Engineering, Guangdong University of Technology, Guangzhou 5100063Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, PO Box 912, Beijing 1000834State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 5102755South China Institute of Environmental Science, MEP, Guangzhou 5100066Success Electronics Co. Ltd., Shenzhen 518132
Transient Reorientation of a Doped Liquid Crystal System under a Short Laser Pulse
LI Tao1, XIANG Ying2,3, LIU Yi-Kun4, WANG Jian5, YANG Shun-Lin6
1College of Chemistry and Life Science, China Three Gorges University, Yichang 4430022School of Information Engineering, Guangdong University of Technology, Guangzhou 5100063Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, PO Box 912, Beijing 1000834State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 5102755South China Institute of Environmental Science, MEP, Guangzhou 5100066Success Electronics Co. Ltd., Shenzhen 518132
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 50ns pulse duration 532nm YAG laser pulse is observed to decrease from 800mJ/mm2 to 0.6mJ/mm2 after the addition of 1 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.
Abstract：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 50ns pulse duration 532nm YAG laser pulse is observed to decrease from 800mJ/mm2 to 0.6mJ/mm2 after the addition of 1 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.
LI Tao;XIANG Ying;LIU Yi-Kun;WANG Jian;YANG Shun-Lin. Transient Reorientation of a Doped Liquid Crystal System under a Short Laser Pulse[J]. 中国物理快报, 2009, 26(8): 86108-086108.
LI Tao, XIANG Ying, LIU Yi-Kun, WANG Jian, YANG Shun-Lin. Transient Reorientation of a Doped Liquid Crystal System under a Short Laser Pulse. Chin. Phys. Lett., 2009, 26(8): 86108-086108.
[1] Durbin S D et al 1981 Phys. Rev. Lett. 47 1411 [2] Hsiung H et al 1984 Phy. Rev. A 30 1453 [3] Hu X D et al 2003 Acta Phys. Sin. 52 192 (inChinese) [4] Janossy I 1994 Phys. Rev. E 49 2957 [5] Gibbons W M et al 1991 Nature 351 49 [6] Chen A G and David J B 1992 Opt. Lett. 17 441 [7] Andy Y G FUH et al 2003 Jpn. J. Appl. Phys. 424406 [8] Lin Z Y et al 2000 Phys. Lett. A 270 326 [9] Xiang Y et al 2008 J. Appl. Phys. 104 063107 [10] Xiang Y et al 2006 Phys. Lett. A 357 159 [11] Khoo I C et al 1993 IEEE J. Quantum Electron. 29 1444 [12] Iacobescu G et al 2008 J. Magn. Magn. Mater. 320 2180 [13] Simoni F et al 1999 J. Phys.: Condens. Matter 11 439 [14] Egami C and Suzuki Y 1997 Appl. Phys. B 64471 [15] Serak S V et al 2002 Liquid Crystals 29 19 [16] Kovalev A et al 2000 Opt. Commun. 183 503 [17] Rodriguez F J et al 2005 J. Chem. Phys. 123204706
2009, Vol. 26 
