胆甾相液晶微激光器的多功能化构筑及结构与性能关系研究

The application of cholesteric liquid crystals (CLCs) in photonic field is now raising more and more scientific concerns. The key is the spontaneous helical structure that leads to the periodic change of refractive index and therefore forms the photonic band gap (PBG). Dye doped cholesteric liquid crystals (DDCLCs) can give rise to a mirrorless and tunable laser emission located at the band edge. Miniaturization of DDCLC lasers for optical integration and lab-on-a-chip applications is important to achieve practical breakthroughs. Different from the single emulsion system composed of liquid crystal droplets, the “core-shell microstructure” in double/multiple emulsions exhibits novel characteristic. This project proposes to adopt microfluidic technology to fabricate specific “core-shell microstructure”-type DDCLC microlasers with one or more stabilized inner cores. The main objective of our research is to optimize the DDCLC proportion, achieve multifunctional microlasers with multi-wavelength/white light emission properties and attempt to improve the laser performance using the surface plasmon resonance (SPR) and multiple scattering effect. Based on the study of structure-property relationship and the mechanism of the interaction between light and the “core-shell microstructure”, we will further investigate pumping methods for optical integration and lab-on-a-chip applications which are based on waveguide-coupling. The current research follows the path of combining “artificial microstructure” with “self-assembly microstructure” and will lead to a novel-class of DDCLC microlasers and provide critical design principles, fabrication technologies and the development of related theories.

胆甾相液晶在光子学领域中的应用日益引起广泛关注，关键在于自发形成螺旋结构导致的空间折射率周期变化。由此形成光子带隙，掺杂染料后可实现无需反射镜、可调谐的带边激光发射。染料掺杂胆甾相液晶（DDCLC）激光器的微型化面向芯片实验室（Lab-on-a-chip）应用，是获得实用化突破的重要途径之一。区别于液晶液滴乳液体系，“核壳微结构”将赋予其新颖的特性。项目提出用微流控技术制备具有单个或多个稳定内核的“核壳微结构”型DDCLC微型激光器，实现液晶体系优化、多功能复合、多波长及白光激光发射，以及利用表面等离子体共振（SPR）效应与多重散射调控、改善激光性能的方法。探索结构与性能之间的关联规律，并在阐释光与“核壳微结构”之间相互作用机理的基础上，研究波导耦合泵浦产生激光发射的技术。项目遵循“人工微结构”与“自组装微结构”结合的路径，为开发一类新型微型激光器提供材料设计思想、关键制备技术与理论积累。

胆甾相液晶在光子学领域中的应用日益引起广泛关注。染料掺杂胆甾相液晶（DDCLC）激光器的微型化面向芯片实验室（Lab-on-a-chip）应用，是获得实用化突破的重要途径之一。本项目研究了双重乳液型DDCLC微激光器，确认在胆甾相液晶核壳微结构中存在分布布拉格反射（DBR，亦即法布-珀罗，Fabry-Pérot，FP）、分布反馈（DFB）及回音壁（WGM）三种模式的激光。研究了具有双增益和单增益的两种类型的三重乳液微激光器的激光发射行为，实现了对多个谐振腔中混合激光模式的灵活控制，并展示了作为具有自校正特性的双波长比值型温度传感的应用。开发了连续批量产生具有可控直径和厚度的胆甾相液晶聚合物（PCLC）微盘的离心微流控技术，分别演示PCLC微盘在微激光器和光学条形码中的潜在应用。进一步研究了双重乳液型胆甾相液晶壳的结构色，获得可磁控移动排列的选择性光反射图案。并借助浮力作用与渗透压差，形成独特的碗状光子学微结构，获得内反射导致的结构色环。这种新结构有望用于光学安全或生物分析编码、应变和温度响应的比色传感器等面向未来液晶非显示应用的先进光子学领域。项目遵循“人工微结构”与“自组装微结构”结合的路径，为开发一类新型微型激光器和结构色介质提供了材料设计思想、关键制备技术与理论积累。