论文标题
自组装的胶体晶体中的随机性可以通过粒子形状和内部结构扩大光子带隙
Randomness in self-assembled colloidal crystals can widen photonic band gaps through particle shape and internal structure
论文作者
论文摘要
使用计算机模拟，我们探讨了自组装光子晶体中热噪声诱导的随机性如何影响其光子带隙（PBG）。我们考虑一个二维光子晶体，该晶体由无限长度的平行介电硬杆组成，带有圆形或方形横截面。我们发现PBG可以在各种中间堆积密度中存在。违反直觉，尽管在任何自组装结构中固有的随机性，但最大的带隙并不总是出现在晶体最有序的堆积密度上。对于在中间堆积密度下具有方形横截面的杆，我们发现自组装（即热）系统的横向磁性（TM）带隙可以大于在完美平方晶格中排列的相同杆的横向磁带隙。通过考虑空心杆，我们发现横向电动（TE）模式的带隙可以大大增加，而TM模式的横向距离可以显着改善固体棒。我们的研究表明，尽管由热噪声引起的位置和定向随机性，但粒子形状和内部结构仍可用来设计自组装系统的PBG。
Using computer simulations, we explore how thermal noise-induced randomness in a self-assembled photonic crystal affects its photonic band gaps (PBGs). We consider a two-dimensional photonic crystal comprised of a self-assembled array of parallel dielectric hard rods of infinite length with circular or square cross section. We find the PBGs can exist over a large range of intermediate packing densities. Counterintuitively, the largest band gap does not always appear at the packing density where the crystal is most ordered, despite the randomness inherent in any self-assembled structure. For rods with square cross section at intermediate packing densities, we find that the transverse magnetic (TM) band gap of the self-assembled (i.e. thermal) system can be larger than that of identical rods arranged in a perfect square lattice. By considering hollow rods, we find the band gap of transverse electric (TE) modes can be substantially increased while that of TM modes show no obvious improvement over solid rods. Our study suggests that particle shape and internal structure can be used to engineer the PBG of a self-assembled system despite the positional and orientational randomness arising from thermal noise.
