Quasi Symmetric Moderate Refractive Index Photonic Crystal Waveguides on Mesoporous Substrates

我们提出了光波在含有有限二维光子晶格结构的聚合物波导薄膜中传播的基本方面的研究。我们最近在这种由纳米结构非晶聚合物制成的具有中等折射率对比度的有限二维光子晶体板波导中发现了单折射率受限波传播和止隙。研究这种新型光子晶体概念的动机源于这些材料在1.3 μ m波长处（某些聚合物也在1.5 μ m波长处）的低本征光学损耗，以及可以实现的大模式分布。在未来的技术应用中，当这种波导与单模硅光纤耦合时，这些可能会起到保持插入损耗小的作用。本课题的第一部分是对我们最近工作的延伸，旨在阐明几何参数和对称性对聚合物光子晶体平板波导中波传播的影响。在这里，我们感兴趣的是研究无摄动晶格和线性缺陷。在第二部分中，我们想要阐明在什么条件下光子晶体聚合物板的双约束引导光波是可能的。最后，我们计划研究光波在由新型光电聚合物制成的光子晶体板中的传播。例如，我们打算阐明这种结构中窄带缺陷态的电光调谐电位。对于我们系统的理论计算，我们使用三维有限差分时域和平面波方法来研究不同频率，偏振和传播方向的波的透射和反射。我们将通过电子束光刻和反应性离子刻蚀技术实现有前途的低损耗结构，然后对它们进行光谱表征。

We propose the research on fundamental aspects of optical wave propagation in thin polymer waveguiding films containing finite two dimensional (2d) photonic crystal lattice structures. We recently found singly index confined wave propagation and stop gaps in such finite 2d photonic crystal slab waveguides made from nanostructured amorphous polymers with a moderate refractive index contrast. The motivation to investigate this novel photonic crystal concept stems from the low intrinsical optical losses in these materials at 1.3µm wavelength (and also at 1.5µm in certain polymers) and from the large mode profiles that can be achieved. These may play a role to keep insertion losses small when such waveguides are coupled to monomode silica fibers in future technical applications. Extending our recent work, the proposed project intends, in the first part, to clarify the influence of geometrical parameters and symmetry on the wave propagation in polymer photonic crystal slab waveguides. Here, we are interested in investigating unperturbed lattices and linear defects. In the second part, we want to clarify under which conditions doubly confined guiding of light waves in photonic crystal polymer slabs is possible. Finally, we plan to investigate optical wave propagation in photonic crystal slabs made from novel electrooptical polymers. For instance, we intend to elucidate the electrooptical tuning potential of narrow band defect states in such structures. For theoretical calculations of our systems we use 3d-finite difference time domain and plane wave methods to investigate the transmission and reflection of waves of different frequencies, polarizations and directions of propagation. We will realize promising low loss structures by electron beam lithography and reacitive ion etching techniques and then characterize them spectroscopically.