Sidewall control of multistate switchable photonic devices

多电平、多稳态可切换相位结构的发展对于光子交换具有重要意义，因为光通信交换机中的双/多稳态将使(i)在停电后增强网络安全性，因为设备将继续运行并具有光学透明性，以及（ii）冗余管理，其中半永久重路由可以很容易地实现。在这个项目中，我们以最近的工作为基础，通过在平面排列的液晶层中微结构侧壁来控制排列，我们已经证明了不仅是双稳定的可能性，而且是多稳定的可能性。这种方位角双稳定性先前已经在使用表面光栅、表面双光栅和在其中一个限制衬底上的柱的周期性阵列的液晶器件中得到了报道。然而，在提议的工作中，侧壁的使用避免了与表面结构的折射率匹配的需要，并允许在基板表面具有更多的功能，例如，它可以用作有源波导包层。应用数学家莫特伦博士（斯特拉斯克莱德大学）和材料物理学家布朗博士（诺丁汉特伦特大学）之间的合作，使这种新方法从理论上的可能性发展到可行性的实际演示。拟议的项目寻求资金来创建具有稳定静态状态的新结构，研究状态之间的动态切换，并研究多稳定结构的光学和衍射特性。

The development of multilevel, multistable switchable phase structures is of significant importance for photonic switching since bi/multistability in optical telecommunications switches will enable (i) enhanced network security after a power outage, since the device would continue to operate and be optically transparent, and (ii) redundancy management, where semi permanent re-routing can easily be implemented. In this project, we build on recent work where we have demonstrated the possibility of not only bistability, but multistability, by micro-structuring the sidewall in a planar aligned liquid crystal layer in order to control alignment. Such azimuthal bistability has previously been reported in liquid crystal devices using surface gratings, surface bi-gratings and periodic arrays of posts on one of the confining substrates. However, in the proposed work the use of the sidewall avoids the need for index matching with surface structures and allows for more functionality in the substrate surface, for instance so that it can be used as an active waveguide cladding. The collaboration between an applied mathematician, Dr Mottram (Strathclyde University), and a materials physicist, Dr Brown (Nottingham Trent University), has allowed this new approach to develop from theoretical possibility to a practical demonstration of feasibility. The proposed project seeks funding to create novel structures that possess stable static states, to investigate dynamic switching between the states, and to investigate the optical and diffractive properties of multistable structures.