电场控制胶体光子晶体对激光输出波长的调谐研究

Due to the band edge enhancement and local field enhancement effects, photonic crystals can be used as resonant cavity of laser, while lasing wavelength can be easily tuned by changing the wavelength position of photonic band gap. In this research, after silica coating and surface modification with negatively charged functional groups, monodispersed microspheres will be suspended in a liquid phase such as water or ionic liquid. If forces among the microspheres such as interparticle electrostatic repulsion, gravity, and buoyancy are balanced, they can self-assemble into long-range ordered crystalline arrays in solution without contacting each other, namely ionic colloidal crystals. When applying an external electric field, the balance among the forces will be broken and consequently change the interparticle distance. Thus, the wavelength position of photonic band gap of colloidal photonic crystal can be modulated, and the wavelength tuning of lasing output can be realized. Comparing with the traditional responsive photonic crystals based on polymeric backbone materials, this ionic colloidal photonic crystal lasing system shows advantages as electro-tunability, faster response rate, better reversibility and stability. These advantages may pave the way to the real application of electro-tuning photonic crystal laser.

因带边增强效应和局域场增强效应，光子晶体可以作为谐振腔被用于激光体系且激光输出波长可以通过改变光子带隙波长位置来进行调谐。在本课题中，通过将单分散高折光率微球表面进行二氧化硅包覆和负电荷基团修饰，在水或离子液体中分散，微球颗粒间的静电排斥力与重力、浮力等达到平衡，形成长程有序三维排列，即胶体悬浮液光子晶体。施加外加电场，微球颗粒间受力平衡被改变，使微球间距也发生改变，进而引起光子晶体光子带隙波长位置的变化，最终实现激光输出波长的调谐。相比于传统基于聚合物骨架材料的响应性光子晶体，这种胶体悬浮液光子晶体激光体系具有可电场调控的、响应时间快、稳定性强等优点，对电场调控光子晶体激光的实际应用有重要意义。

因带边增强效应和局域场增强效应，光子晶体可以作为谐振腔被用于激光体系且激光输出波长可以通过改变光子带隙波长位置来进行调谐。在本课题中，通过将单分散高折光率微球表面进行二氧化硅包覆和负电荷基团修饰，或将单分散Fe3O4微球表面修饰聚吡咯烷酮（PVP），在水或乙醇中分散，在电场下获得ZnS@SiO2微球与电场之间引力和颗粒间的静电排斥力的平衡，或在磁场下获得Fe3O4@PVP微球间磁极-磁极作用力与静电排斥力的平衡。形成长程有序排列，即胶体悬浮液光子晶体。改变外加电场或外加磁场，微球颗粒间受力平衡被改变，使微球间距也发生改变，进而引起光子晶体光子带隙波长位置的变化，最终实现激光输出波长的调谐。相比于传统基于聚合物骨架材料的响应性光子晶体，这种胶体悬浮液光子晶体激光体系具有可电场调控的、响应时间快、稳定性强等优点，对电场调控光子晶体激光的实际应用有重要意义。本项目已实现磁场控制光子晶体激光输出波长的调谐，波长调谐范围达20 nm。电场控制光子晶体激光输出波长调谐的工作仍在进行当中。