| Summary: | 碩士 === 國立中山大學 === 光電工程學系研究所 === 106 === 2D layer structures have been attracted plenty of attention due to their remarkable properties and application potential. To realize 2-D material nonlinear optical applications, including wavelength generation, ultrafast optical processing, and saturable absorber for ultrafast laser, the information of optical nonlinearity property for given material is very important. In this thesis, using home-made Z-scan measurement with tunable peak intensity ranging from 103 to 108 W/cm2, Ge/SiC super-lattice layers structure and Bi2Te3 were studied.
In the first part, using HVPE growth, Ge/Si super-lattice layer structures were fabricated. The thickness of Ge or SiC was 10nm and the name of Ge/SiC pair and total thickness are 10 and 200nm, respectively. The clear power dependent Z-scan measurement was observed. The increasing saturation intensity from to and almost fixed two photon absorption coefficient of as increasing excitation peak intensity from 15.8 to 132 were analyzed. The n2 of around 4.12 was accordingly estimated.
In the second part, ultra-low peak intensity (103 to 105 W/cm2) z-scan measurement was proposed and buildup for understanding the discontinuity of conventional nonlinear transmission with low and high pulse energy. The two photon absorption behavior was observed and is with tremendous large coefficient of for excitation power of 100W. This can be therefore used to interpret and resolve the discontinuity. The clear self-defocusing phenomena was investigated as well.
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