基于光栅结构的等离子体复合器件的特性及应用研究

发布时间：2018-06-02 21:57

本文选题：光栅 + 表面等离子体　；参考：《合肥工业大学》2017年硕士论文

【摘要】：近些年来,表面等离子体器件已经成为学术研究的一个重要研究方向和热点。这种等离子器件在光场调控、生物传感和光学缓存等方面有着重要的应用前景。传统的表面等离子体的激发方式如棱镜耦合、波导耦合、近场激发等都有着许多不足之处,阻碍了其在光学方面的发展和应用。而光栅耦合的方式,由于其结构尺寸小、易集成、可精确设计控制等,逐渐成为复合型等离子器件的最佳选择。本文根据等离子体相关理论并借助FDTD数值仿真方法重点研究基于光栅的等离子体复合器件的相关特性及应用。具体研究内容如下:(1)提出了一种基于金属光栅阵列的多光谱、空间选择性的等离子体传感器。通过适当地调整金属光栅阵列的几何参数,可以选择性地在结构的不同区域激发相应的等离子体模式来得到增强的光场。模拟结果显示,这些共振模式可以同时在结构的不同空间位置及不同波长下实现。当生物分子薄膜吸附在光栅内壁时,共振峰有相对大的红移(57nm),相应的强度差也比在金属表面增强近10倍。此外,当单层BSA蛋白分子吸附在光栅内壁时,通过调整内壁宽度可以得到超过80nm的移动。这些结果表明我们所设计的结构可以作为具有空间和频谱选择特性的生物传感器。(2)设计了一种基于增益补偿作用的金属光栅高效折射率传感器。通过分析发现金属欧姆损失效应阻碍了纳米光栅阵列EOT效率的提高。为了补偿金属的固有损耗,我们提出了将金属结构嵌入掺有非线性活性增益物质的媒介中。当增益效率达到相应的阈值时,共振峰λ2对应的品质因素FOM*可以达到39100。这种对环境折射率变化具有超高灵敏度的增益光栅结构将在生物医学及环境探测等方面有广阔的应用。(3)提出了一种基于介质光栅的新型石墨烯等离子体系统。文中系统地研究了石墨烯-渐进硅光栅结构上SPP的局域效应与光学特性。理论及数值结果表明,在一个宽带范围内,不同频率的SPP波将被局域在石墨烯表面的不同位置,可以应用为宽带光谱仪。基于此理论,我们预测了不同频率SPP波在结构表面的局域位置及相应的群速度。通过适当地调节栅压,局域的SPP波可以被释放并继续在石墨烯表面传播或从结构末端输出。接着文中继续研究了该慢光系统的开光特性,结果表明只需调整栅压大小就可动态地控制光开光的“开”和“关”。
[Abstract]:In recent years, surface plasma devices have become an important research direction and hot spot in academic research. This kind of plasma device has important applications in light field control, biosensor and optical buffer. Traditional surface plasma excitation methods such as prism coupling waveguide coupling and near-field excitation have many shortcomings which hinder their development and application in optics. Because of its small size, easy integration, precise design and control, grating coupling has gradually become the best choice for composite plasma devices. Based on plasma correlation theory and FDTD numerical simulation method, this paper focuses on the characteristics and applications of grating-based plasma recombination devices. A multispectral and spatially selective plasma sensor based on metal grating array is proposed. By adjusting the geometric parameters of the metal grating array appropriately, the enhanced light field can be obtained by selectively exciting the corresponding plasma modes in different regions of the structure. The simulation results show that these resonant modes can be realized simultaneously at different spatial positions and different wavelengths of the structure. When the biomolecular film is adsorbed on the inner wall of the grating, the resonance peak has a relatively large red shift of 57 nm, and the corresponding intensity difference is nearly 10 times higher than that on the metal surface. In addition, when the monolayer BSA protein molecules are adsorbed on the inner wall of the grating, the inner wall can be shifted over the 80nm by adjusting the width of the inner wall. These results show that the structure we designed can be used as a biosensor with spatial and spectrum selection characteristics. A metal grating high efficiency refractive index sensor based on gain compensation is designed. It is found that the metal ohmic loss effect hinders the improvement of EOT efficiency of nanocrystalline grating arrays. In order to compensate for the inherent loss of metals, we propose to embed metal structures into media with nonlinear active gain materials. When the gain efficiency reaches the corresponding threshold, the quality factor FOM * corresponding to the resonance peak 位 2 can reach 39100. A novel graphene plasma system based on dielectric grating is proposed, which has high sensitivity to environmental refractive index change and will be widely used in biomedicine and environmental detection. In this paper, the local effect and optical properties of SPP on graphene-progressive silicon grating structure are systematically studied. The theoretical and numerical results show that in a wide band range, SPP waves with different frequencies will be localized at different positions on the surface of graphene and can be used as wideband spectrometers. Based on this theory, we predict the local positions of SPP waves with different frequencies on the structural surface and the corresponding group velocities. By adjusting the gate voltage appropriately, the localized SPP wave can be released and continue to propagate on the surface of graphene or output from the end of the structure. Then the open characteristics of the slow light system are studied. The results show that the "open" and "turn" of the light can be dynamically controlled by adjusting the gate voltage.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN25;TP212

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