光学暗态及其对亚波长波导传输特性的调制

发布时间：2018-04-04 21:32

本文选题：光学暗态　切入点：等离子诱导透明　出处：《哈尔滨工业大学》2015年硕士论文

【摘要】：金属—介质—金属(Metal-Dielectric-Metal,MDM)表面等离激元(Surface Plasmon Polaritons,SPPs)波导结构中光的传播及耦合特性已经得到了广泛研究,因其能够有效突破光学衍射极限的束缚,能将光场束缚在纳米尺度并进行灵活可控地传输调控,因而广泛应用于微钠光学领域。正因为表面等离激元对光在纳米尺度或深亚波长尺度上的束缚和操控能力,我们可以利用基于SPP的等离子波导系统中模拟实现很多原子系统中的特殊光调控效应,比较重要的是电磁诱导透明(Electromagnetically Induced Transparency,EIT)和Fano共振等。本文针对以上特点,结合理论分析及数值电磁仿真,从光学明态和暗态及其相互作用的角度研究光在表面等离子波导系统中的传输特性及其调控机理和手段。首先,针对MDM波导中传输SPP波的相关特点以及谐振腔模式耦合特性,系统地分析了光学明态,尤其是光学暗态以及它们之间的相互作用在MDM波导系统中对透射谱的调控。结果表明光学暗态在不同作用方式下能够显著地调节透射谱线形,形成类似于EIT的等离子诱导透明(Plasmon Induced Transparency,PIT)现象。针对多模耦合共振系统,我们使用时域耦合模理论(Temporal Coupled Mode Theory,TCMT)分析了正交和非正交模式对MDM波导透射谱的调制情况。理论和数值结果表明存在正交模式的共振系统的透射谱迥异于非正交模式的情形。当两个正交模式的频率差减小到特定阈值以下,就会形成全透特性,因此可以说这两个模式对于波导系统来说都是不可见的。基于有限元方法的全波数值模拟结果能够有效地与理论分析吻合。此外,针对多模(多腔)耦合共振系统的周期性MDM波导结构,提出结合时域耦合模理论和传输矩阵方法,研究了由多重Bragg反射引起的Bragg带隙和局域共振态形成的“极化子”(Polariton)带隙,以及两者相互作用对波导透射谱的调制特性。结果表明不同的周期长度引起的Bragg带隙和在空间上通过级联共振腔相互耦合形成的杂化模式“极化子”带隙一旦发生部分或者全部重叠,那么在重叠谱区域就会形成一个微通带(mini-band),在这里表面等离子体波发生明显的相干隧穿效应,表现为透射谱中形成了明显的多PIT现象。本文研究结果对于设计新型亚波长相干波导器件具有一定指导意义,可用于构建基于MDM结构的滤波器、路由器、以及加减器等。
[Abstract]:The propagation and coupling characteristics of light in the surface of metal-dielectric metallic-metallic-metallics (MDM) surface surface Plasmon Polaritons (SPPsS) waveguide have been extensively studied because it can effectively break through the confinement of optical diffraction limit.It is widely used in the field of microsodium optics due to its ability to bind the light field to nanometer scale and to control the transmission flexibly.Because of the ability of surface isopherons to bind and manipulate light on nanometer scale or deep subwavelength scale, we can simulate and realize the special optical modulation effect in many atomic systems by using SPP based plasma waveguide system.The most important ones are electromagnetically Induced transparent and Fano resonance.In view of the above characteristics, combined with theoretical analysis and numerical electromagnetic simulation, this paper studies the transmission characteristics of light in the surface plasma waveguide system from the point of view of optical light state and dark state and their interaction, as well as the control mechanism and means.Firstly, aiming at the characteristics of transmitting SPP waves in MDM waveguides and the coupling characteristics of resonator modes, the optical light states, especially the optical dark states and their interactions in the MDM waveguide system, are systematically analyzed.The results show that the optical dark state can significantly adjust the transmission line shape in different modes of action and form plasmon Induced transparent bit phenomenon similar to that of EIT.For multimode coupled resonance systems, the time domain coupled mode theory (Temporal Coupled Mode Theoryn) is used to analyze the modulation of transmission spectra of MDM waveguides by orthogonal and non-orthogonal modes.The theoretical and numerical results show that the transmission spectra of resonance systems with orthogonal modes are different from those of non-orthogonal modes.When the frequency difference between the two orthogonal modes is reduced to below a specific threshold, the fully permeable characteristics will be formed, so it can be said that the two modes are invisible to the waveguide system.The results of full wave numerical simulation based on finite element method are in good agreement with theoretical analysis.In addition, for the periodic MDM waveguide structure of multi-mode (multi-cavity) coupled resonance system, a time-domain coupled mode theory and a transmission matrix method are proposed.The Bragg band gap caused by multiple Bragg reflection and the polaron band gap formed by the local resonance state are studied, and the modulation characteristics of the waveguide transmission spectrum by the interaction of the two kinds of band gaps are studied.The results show that the band gap of Bragg caused by different period length and the hybrid mode "polaron" band gap formed by coupling each other through cascaded resonators in space are partially or completely overlapped.Then a micro-passband mini-band is formed in the overlapping spectrum region where the coherent tunneling effect of the surface plasma wave is obvious and the phenomenon of multiple PIT is formed in the transmission spectrum.The results of this paper are useful for the design of new subwavelength coherent waveguide devices, and can be used to construct filters, routers, adders and subducers based on MDM structure.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN25

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