Sidewall control of multistate switchable photonic devices

由于光电信交换机中的双/多稳定将实现(I)在停电后增强的网络安全性，因为该设备将继续运行并且是光学透明的，并且(Ii)冗余管理，其中可以容易地实施半永久重新路由，因此，多级、多稳定的可切换相位结构的开发对于光子交换非常重要。在这个项目中，我们以最近的工作为基础，通过在平面取向液晶层中微结构侧壁来控制取向，不仅证明了双稳的可能性，而且证明了多稳的可能性。这种方位双稳态先前已经在使用限制衬底之一上的表面栅格、表面双栅格和柱子的周期阵列的液晶器件中被报道过。然而，在所提出的工作中，侧壁的使用避免了与表面结构的折射率匹配的需要，并允许基片表面具有更多的功能，例如，使得它可以用作有源波导包层。应用数学家莫特特伦博士(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了可行性的实际演示。该项目寻求资金，以创造具有稳定静态的新型结构，研究状态之间的动态转换，并研究多稳态结构的光学和衍射性质。

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.