Perfect reflection by dielectric subwavelength particle arrays: causes, implications, and technology
Perfect reflection by dielectric subwavelength particle arrays: causes, implications, and technology
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DOI：
10.1117/12.2578953
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发表时间：
2021-03
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通讯作者：
R. Magnusson;Y. Ko;K. Lee;Pawarat Bootpakdeetam;Nasrin Razmjooei;F. A. Simlan;Ren-Jie Chen;Joseph A. Buchanan-Vega;D. Carney;Hafez Hemmati;N. Gupta
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作者：
R. Magnusson;Y. Ko;K. Lee;Pawarat Bootpakdeetam;Nasrin Razmjooei;F. A. Simlan;Ren-Jie Chen;Joseph A. Buchanan-Vega;D. Carney;Hafez Hemmati;N. Gupta
谐振介电纳米或微米结构的周期性阵列提供跨光谱带的完美反射，其范围可通过设计控制。在共振时，即使在形成为膜或位于基板上的单个亚波长层中，阵列也会产生这种结果。共振效应（称为导模共振）是一维 (1D) 或二维 (2D) 周期性调制薄膜的基础。 40 年来人们就知道，当入射光与泄漏布洛赫型波导模式耦合时，这些显着效应就会产生，这些波导模式在辐射能量的同时横向传播。周期性晶格的完美反射源自粒子集合，而不是源自组成粒子共振。我们证明完美反射与晶格粒子形状无关，因为它对于所有粒子形状都会出现。布洛赫模式介导的零级反射率的共振波长主要由给定晶格的周期控制。这是因为周期对晶格的均匀有效介质折射率有直接的、主要的影响，晶格控制产生谐振的模式所经历的有效模式指数。近年来，超材料领域蓬勃发展，相关出版物层出不穷。该输出的很大一部分集中在反射器上，声称局部法布里-珀罗或米氏共振会导致完美反射，而忽略泄漏的布洛赫模式视点。在本文中，我们提出了显示横向泄漏布洛赫模式的重要性的关键点，同时揭示了局部模式解释的缺点。总结了相关技术及其应用的现状。最重要的信息是，正是粒子的组合提供了包括完美反射在内的所有重要效果。
Periodic arrays of resonant dielectric nano- or microstructures provide perfect reflection across spectral bands whose extent is controllable by design. At resonance, the array yields this result even in a single subwavelength layer fashioned as a membrane or residing on a substrate. The resonance effect, known as guided-mode resonance, is basic to modulated films that are periodic in one dimension (1D) or in two dimensions (2D). It has been known for 40 years that these remarkable effects arise as incident light couples to leaky Bloch-type waveguide modes that propagate laterally while radiating energy. Perfect reflection by periodic lattices derives from the particle assembly and not from constituent particle resonance. We show that perfect reflection is independent of lattice particle shape in the sense that it arises for all particle shapes. The resonance wavelength of the Bloch-mode-mediated zero-order reflectance is primarily controlled by the period for a given lattice. This is because the period has direct, dominant impact on the homogenized effective-medium refractive index of the lattice that controls the effective mode index experienced by the mode generating the resonance. In recent years, the field of metamaterials has blossomed with a flood of attendant publications. A significant fraction of this output is focused on reflectors with claims that local Fabry-Perot or Mie resonance causes perfect reflection with the leaky Bloch-mode viewpoint ignored. In this paper, we advance key points showing the essentiality of lateral leaky Bloch modes while laying bare the shortcomings of the local mode explanations. The state of attendant technology with related applications is summarized. The take-home message is that it is the assembly of particles that delivers all the important effects including perfect reflection.