Dependence of Nonlinear Optical Response of Anatase TiO2 on Shape and Excitation Intensity

作     者：郭路华 王迎威 蒋永强 肖思 何军 

作者机构：Hunan Key Laboratory of Super Microstructure and Ultrafast Process School of Physics and Electronics Central South University Changsha 410083 

出 版 物：《Chinese Physics Letters》 (中国物理快报（英文版）)

年 卷 期：2017年第34卷第7期

页      面：266-270页

核心收录：

学科分类：070207[理学-光学] 080901[工学-物理电子学] 07[理学] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 080401[工学-精密仪器及机械] 0804[工学-仪器科学与技术] 0805[工学-材料科学与工程（可授工学、理学学位）] 0704[理学-天文学] 0803[工学-光学工程] 0702[理学-物理学] 

基　　金：Supported by the National Natural Science Foundation of China under Grant Nos 11404410 and 11504105 

主　　题：NP Dependence of Nonlinear Optical Response of Anatase TiO2 on Shape and Excitation Intensity NLO TiO 

摘      要：Nonlinear optical （NLO） properties of anatase TiO2 with nanostructures of nanopaxticle （NP）, nanowire （NW） and annealed nanowire （NWA） are studied by open-aperture and closed-aperture Z-scan techniques with a fem- tosecond pulsed laser at wavelengths of 532 nm and 780 nm simultaneously. At 532 nm, when increasing excitation intensity, NLO absorption of TiO2 NPs transforms from saturable absorption to reverse-saturable absorption. However, NWs and NWAs exhibit the opposite change. At 780nm, all samples show reverse-saturable absorption, but have different sensitivities to excitation intensity. Due to the larger surface-to-volume ratio of NPs and less defects of NWAs by annealing, nonlinear optical absorption coet^icients follow the order NPs≥ NWs≥ NWAs. The results also show that these shape and annealing effects axe dominant at low excitation intensity, but do not exhibit at the high excitation intensity. The NLO refractive index of NPs shows a positive linear relationship with the excitation intensity, whereas NW and NWAs exhibit a negative linear relationship. The results could provide some foundational guidance to applications of anatase TiO2 in optoelectronic devices or other aspects.