Trendafilov Simeon, Allen Jeffery W, Allen Monica S, Dev Sukrith U, Li Ziyuan, Fu Lan, Jagadish Chennupati
Air Force Research Laboratory, Munitions Directorate, Eglin AFB, Valparaiso, FL 32542, USA.
Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601, Australia.
Sensors (Basel). 2021 Aug 11;21(16):5420. doi: 10.3390/s21165420.
Semiconductor nanowire arrays have been demonstrated as promising candidates for nanoscale optoelectronics applications due to their high detectivity as well as tunable photoresponse and bandgap over a wide spectral range. In the infrared (IR), where these attributes are more difficult to obtain, nanowires will play a major role in developing practical devices for detection, imaging and energy harvesting. Due to their geometry and periodic nature, vertical nanowire and nanopillar devices naturally lend themselves to waveguide and photonic crystal mode engineering leading to multifunctional materials and devices. In this paper, we computationally develop theoretical basis to enable better understanding of the fundamental electromagnetics, modes and couplings that govern these structures. Tuning the photonic response of a nanowire array is contingent on manipulating electromagnetic power flow through the lossy nanowires, which requires an intimate knowledge of the photonic crystal modes responsible for the power flow. Prior published work on establishing the fundamental physical modes involved has been based either on the modes of individual nanowires or numerically computed modes of 2D photonic crystals. We show that a unified description of the array key electromagnetic modes and their behavior is obtainable by taking into account modal interactions that are governed by the physics of exceptional points. Such models that describe the underlying physics of the photoresponse of nanowire arrays will facilitate the design and optimization of ensembles with requisite performance. Since nanowire arrays represent photonic crystal slabs, the essence of our results is applicable to arbitrary lossy photonic crystals in any frequency range.
半导体纳米线阵列因其高探测率以及在宽光谱范围内可调的光响应和带隙，已被证明是纳米级光电子应用的有前途的候选者。在红外（IR）领域，这些特性更难获得，纳米线将在开发用于检测、成像和能量收集的实用设备中发挥主要作用。由于其几何形状和周期性，垂直纳米线和纳米柱器件自然适用于波导和光子晶体模式工程，从而产生多功能材料和器件。在本文中，我们通过计算建立理论基础，以便更好地理解控制这些结构的基本电磁学、模式和耦合。调整纳米线阵列的光响应取决于操纵通过有损耗纳米线的电磁功率流，这需要深入了解负责功率流的光子晶体模式。先前关于建立所涉及的基本物理模式的已发表工作要么基于单个纳米线的模式，要么基于二维光子晶体的数值计算模式。我们表明，通过考虑由例外点物理支配的模式相互作用，可以获得对阵列关键电磁模式及其行为的统一描述。这种描述纳米线阵列光响应基本物理原理的模型将有助于设计和优化具有所需性能的组件。由于纳米线阵列代表光子晶体平板，我们结果的本质适用于任何频率范围内的任意有损耗光子晶体。
