All-Optical Photorefractive Effect in Bihole-Transporting System Polymeric Composites
HUANG Mao-Mao1, CHEN Zhi-Jian1, ZHANG Jie1, WEI Qun1, LIU Yi-Hong1, GONG Qi-Huang1, BAI Yao-Wen2, CHEN Xiao-Fang2, WAN Xin-Hua2, ZHOU Qi-Feng2
1Department of Physics, State Key Laboratory for Mesoscopic Physics, Peking University, Beijing 100871
2Department of Polymer Science and Engineering, College of Chemistry, Peking University, Beijing 100871
All-Optical Photorefractive Effect in Bihole-Transporting System Polymeric Composites
1Department of Physics, State Key Laboratory for Mesoscopic Physics, Peking University, Beijing 100871
2Department of Polymer Science and Engineering, College of Chemistry, Peking University, Beijing 100871
Abstract： Photorefractive (PR) composites based on poly(N-vinylcarbozale) and azobenzene have been fabricated. Two-beam-coupling and four-wave-mixing phenomena were observed in the absence of an external electric field or prepoling. The maximum two-beam-coupling gain coefficient and the refractive index modulation were measured to be 79cm-1 and 2.2×10-4 respectively. The all-optical-PR phenomenon is explained based on the photoassisted poling of the azo dye by the synergism of the photoisomerization and the longitudinal electric field due to longitudinal intensity gradient of writing light beams. The bi-hole-transporting system provides more charge-carrier traps resulting in improvement of PR performance.
2004, Vol. 21 
