表面等离子体沟道波导实现高效三次谐波产生与受激三光子下转换的理论研究  

Plasmonic Slot Waveguides for Third Harmonic Generation and Third-Order Parametric Down-Conversion

作　　者：孙云旭[1] 张剑宇[1] 

机构地区：[1]哈尔滨工业大学深圳研究生院,广东深圳518055

出　　处：《光学学报》2015年第A01期308-313,共6页Acta Optica Sinica

基　　金：深圳基础研究计划（JCYJ20140417172417146）

摘　　要：三次谐波产生（THG）与三光子参量下转换（TPDC）由于频率跨度大，相位匹配条件很难实现。波导模式色散是有效补偿材料色散的工具。但是THG或TPDC的非线性极化强度为奇函数，如果模场分布存在正负分布，则奇函数几乎为0。提出非对称等离子体沟道波导设计，沟道中引入高阶非线性有机材料（DDMEBT）。晶体硅（Si）在沟道底部以破坏波导的对称性。金属包层采用损耗较小的银（Ag）。通过设计波导几何参数，在基频（FF）零阶模式和第三次诣波（TH）一阶模式间获得了有效的相位匹配条件（PMC），相应THG或TPPC的重叠积分远高于对称波导情况。The researches of third harmonic generation （THG） and third-order parametric down-conversion （TPDC） always encounter the problem of phase mismatching with such a large frequency span. Waveguides modal dispersion is an effective tool to compensate the material dispersion. However, the nonlinear polarization form of THG or TPDC is an odd function that will be almost zero if the mode field distribution contains opposite sign components. Several asymmetric plasmonic slot waveguides infiltrated in nonlinear organic material （2-[-4（dimethylamino）phenyl^-3-f[-4- （dimethylamino） phenyl~ ethynylgbuta-1, 3-diene-1, 1, 4-tetracarbonitrile） （DDMEBT） with high third-order susceptibility are proposed. Silicon （Si） is used to fill the bottom metallic slot region to break the symmetry of the waveguide. Silver （Ag） is considered to be the metal medium due to its low loss. The needed phase-matching condition （PMC） is satisfied between the zeroth mode at fundamental frequency （FF） and the first mode at third harmonic （TH） by appropriate designing the waveguide geometrical parameters. The corresponding overlap factor for THG or TPDC is much larger than the symmetric distribution.

关 键 词：非线性光学 参量下转换 等离子体沟道波导 相位匹配 模式色散 

分 类 号：TN929[电子电信—通信与信息系统]