Zhang Feifei, Atsumi Taisuke, Xu Xiaolun, Murai Shunsuke, Tanaka Katsuhisa
Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
Light, Nanomaterials, Nanotechnologies (L2n), University of Technology of Troyes (UTT) & CNRS ERL 7004, 12 rue Marie Curie, Troyes, France.
Nanophotonics. 2021 Nov 29;11(2):275-288. doi: 10.1515/nanoph-2021-0327. eCollection 2022 Jan.
To date, the plasmonic nanostructure utilized for magneto-optical (MO) enhancement has been limited to noble metals with resulted enhancement in the green-red part of visible spectrum. In this study, we fabricated a diffractive hexagonal array composed of Al nanoparticles (NPs) with a thin 7.5 nm ferromagnetic film and pushed the enhanced Faraday rotation (FR) into the blue to green range of the visible light. The freedom and ability to control the working spectral region in the whole visible range from 400 to 800 nm were also demonstrated by changing the lattice constant and the dielectric environment of plasmonic nanostructures. Particularly, in the blue range we obtained the maximum FR 0.57° at 410 nm with a broad boosting region around 0.5° from 400 to 500 nm. Moreover, the largest FR 1.66° was shown at 638 nm by tuning the dielectric environment into a higher refractive index medium. The results of our investigation demonstrate the potential of Al-based magnetoplasmonic effect and offer opportunities to push the MO spectral response out of visible range into the ultraviolet-blue range.
迄今为止，用于磁光（MO）增强的等离子体纳米结构仅限于贵金属，其增强作用出现在可见光谱的绿-红部分。在本研究中，我们制备了一种由铝纳米颗粒（NPs）组成的衍射六边形阵列，并在其上覆盖了一层7.5 nm厚的铁磁薄膜，从而将增强的法拉第旋转（FR）扩展到可见光的蓝-绿范围。通过改变等离子体纳米结构的晶格常数和介电环境，还展示了在400至800 nm的整个可见光范围内控制工作光谱区域的自由度和能力。特别是，在蓝色范围内，我们在410 nm处获得了最大法拉第旋转角0.57°，在400至500 nm范围内有一个约0.5°的宽增强区域。此外，通过将介电环境调整为更高折射率的介质，在638 nm处显示出最大法拉第旋转角1.66°。我们的研究结果证明了基于铝的磁等离子体效应的潜力，并为将磁光谱响应从可见光范围扩展到紫外-蓝光范围提供了机会。
