Prajapati Ashish, Nissan Yuval, Gabay Tamir, Shalev Gil
Department of Electrical and Computer Engineering, Ben-Gurion University of the Negev, POB 653, Beer-Sheva 8410501, Israel.
The Ilse-Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, POB 653, Beer-Sheva 8410501, Israel.
Materials (Basel). 2018 Mar 19;11(3):445. doi: 10.3390/ma11030445.
Silicon light funnels are three-dimensional subwavelength structures in the shape of inverted cones with respect to the incoming illumination. Light funnel (LF) arrays can serve as efficient absorbing layers on account of their light trapping capabilities, which are associated with the presence of high-density complex Mie modes. Specifically, light funnel arrays exhibit broadband absorption enhancement of the solar spectrum. In the current study, we numerically explore the optical coupling between surface light funnel arrays and the underlying substrates. We show that the absorption in the LF array-substrate complex is higher than the absorption in LF arrays of the same height (~10% increase). This, we suggest, implies that a LF array serves as an efficient surface element that imparts additional momentum components to the impinging illumination, and hence optically excites the substrate by near-field light concentration, excitation of traveling guided modes in the substrate, and mode hybridization.
硅光漏斗是相对于入射照明呈倒锥形状的三维亚波长结构。光漏斗（LF）阵列由于其光捕获能力可作为高效吸收层，这与高密度复杂米氏模式的存在有关。具体而言，光漏斗阵列对太阳光谱表现出宽带吸收增强。在当前研究中，我们通过数值方法探究了表面光漏斗阵列与下层衬底之间的光学耦合。我们表明，LF阵列 - 衬底复合体中的吸收高于相同高度的LF阵列中的吸收（增加约10%）。我们认为，这意味着LF阵列作为一种高效的表面元件，为入射照明赋予额外的动量分量，从而通过近场光集中、衬底中传播导模的激发以及模式杂化来光学激发衬底。
