Portal Sabine, Corbella Carles, Arteaga Oriol, Martin Alexander, Mandal Trinanjana, Kahr Bart
Department of Mechanical and Aerospace Engineering, George Washington University, Washington, DC 20052, USA.
Experimental Physics II, Ruhr-University Bochum, 44780 Bochum, Germany.
Nanomaterials (Basel). 2023 Aug 2;13(15):2235. doi: 10.3390/nano13152235.
Optically anisotropic materials were produced via colloidal lithography and characterized using scanning electronic microscopy (SEM), confocal microscopy, and polarimetry. A compact hexagonal array mask composed of silica sub-micron particles was fabricated via the Langmuir-Blodgett self-assembly technique. Subsequently, the mask pattern was transferred onto monocrystalline silicon and commercial glass substrates using ion beam etching in a vacuum. Varying the azimuthal angle while etching at oblique incidence carved screw-like shaped pillars into the substrates, resulting in heterochiral structures depending on the azimuthal angle direction. To enhance the material's optical properties through plasmon resonance, gold films were deposited onto the pillars. Polarimetric measurements were realized at normal and oblique incidences, showing that the etching directions have a clear influence on the value of the linear birefringence and linear dichroism. The polarimetric properties, especially the chiroptical responses, increased with the increase in the angle of incidence.
通过胶体光刻技术制备了光学各向异性材料，并使用扫描电子显微镜（SEM）、共聚焦显微镜和偏振测量法对其进行了表征。通过朗缪尔-布洛杰特自组装技术制备了由二氧化硅亚微米颗粒组成的紧密六边形阵列掩膜。随后，利用真空离子束蚀刻将掩膜图案转移到单晶硅和商用玻璃基板上。在倾斜入射蚀刻时改变方位角，在基板上刻出螺旋状柱体，根据方位角方向产生异手性结构。为了通过等离子体共振增强材料的光学性能，在柱体上沉积了金膜。在垂直入射和倾斜入射下进行了偏振测量，结果表明蚀刻方向对线性双折射和线性二向色性的值有明显影响。偏振特性，尤其是手性光学响应，随着入射角的增加而增强。
