Chen Chun-Wei, Hou Chien-Tsung, Li Cheng-Chang, Jau Hung-Chang, Wang Chun-Ta, Hong Ching-Lang, Guo Duan-Yi, Wang Cheng-Yu, Chiang Sheng-Ping, Bunning Timothy J, Khoo Iam-Choon, Lin Tsung-Hsien
Department of Photonics, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan.
Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
Nat Commun. 2017 Sep 28;8(1):727. doi: 10.1038/s41467-017-00822-y.
Although there have been intense efforts to fabricate large three-dimensional photonic crystals in order to realize their full potential, the technologies developed so far are still beset with various material processing and cost issues. Conventional top-down fabrications are costly and time-consuming, whereas natural self-assembly and bottom-up fabrications often result in high defect density and limited dimensions. Here we report the fabrication of extraordinarily large monocrystalline photonic crystals by controlling the self-assembly processes which occur in unique phases of liquid crystals that exhibit three-dimensional photonic-crystalline properties called liquid-crystal blue phases. In particular, we have developed a gradient-temperature technique that enables three-dimensional photonic crystals to grow to lateral dimensions of 1 cm (30,000 of unit cells) and thickness of 100 μm ( 300 unit cells). These giant single crystals exhibit extraordinarily sharp photonic bandgaps with high reflectivity, long-range periodicity in all dimensions and well-defined lattice orientation.Conventional fabrication approaches for large-size three-dimensional photonic crystals are problematic. By properly controlling the self-assembly processes, the authors report the fabrication of monocrystalline blue phase liquid crystals that exhibit three-dimensional photonic-crystalline properties.
尽管人们为制造大型三维光子晶体以充分发挥其潜力付出了巨大努力，但迄今为止开发的技术仍面临各种材料加工和成本问题。传统的自上而下制造方法成本高且耗时，而自然自组装和自下而上制造方法往往导致高缺陷密度和有限尺寸。在此，我们报告通过控制在具有三维光子晶体特性（称为液晶蓝相）的液晶独特相态中发生的自组装过程，制造出了超大的单晶光子晶体。特别是，我们开发了一种梯度温度技术，使三维光子晶体能够生长到横向尺寸约为1厘米（约30,000个晶胞），厚度约为100微米（约300个晶胞）。这些巨大的单晶表现出具有高反射率、所有维度上的长程周期性以及明确晶格取向的极其尖锐的光子带隙。用于制造大尺寸三维光子晶体的传统方法存在问题。通过适当控制自组装过程，作者报告了具有三维光子晶体特性的单晶蓝相液晶的制造。
