Numerical finite-difference time-domain calculation for extreme enhancement of magneto-optical effect at ultraviolet wavelength using Ni-subwavelength grating on SiO2/Ni structure
Numerical finite-difference time-domain calculation for extreme enhancement of magneto-optical effect at ultraviolet wavelength using Ni-subwavelength grating on SiO2/Ni structure
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DOI：
10.1007/s10043-021-00711-2
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发表时间：
2022-01-11
期刊：
影响因子：
1.2
通讯作者：
Naoi，Yoshiki
中科院分区：
文献类型：
--
作者：
Takashima，Yuusuke;Haraguchi，Masanobu;Naoi，Yoshiki
使用 SiO2/Ni 界面处的表面等离子体激元 (SPP) 与 Ni 亚波长光栅 (SWG) 相结合，以数值方式证明了极性克尔磁光 (MO) 效应的极大增强。利用 SiO2/Ni 界面上 SPP 的 ω-k 色散关系，设计 Ni-SWG 的参数以将 SPP 模式与入射光耦合。采用时域有限差分法计算电磁场分布，以估计和讨论设计结构中MO效应的增强情况。结果表明，由于 SPP 激发，所设计结构的光反射率急剧下降。场分布表明，SPP的高电场不仅集中在Ni衬底上，而且还集中在Ni-SWG上，产生的克尔旋转角比没有SPP的高224倍。研究结果为增强MO效应提供了新的方法；我们的结构实现了极大的MO增强，具有广泛应用的巨大潜力。
An extreme enhancement of the polar Kerr magneto-optical (MO) effect was numerically demonstrated using surface plasmon polaritons (SPPs) at the SiO2/Ni interface combined with the Ni-subwavelength grating (SWG). Utilizing the ω–k dispersion relation for the SPP at the SiO2/Ni interface, the parameters of Ni-SWGs were designed to couple the SPP mode with the incident light. The electromagnetic field distribution was calculated using the finite-difference time-domain method to estimate and discuss the enhancement of MO effect in the designed structure. The results indicated that the reflectance of light for the designed structure dramatically decreased owing to SPP excitations. The field distributions revealed that the high electric field of the SPP was concentrated not only on the Ni substrate but also on Ni-SWG, yielding Kerr rotation angle 224 times higher than that without SPP. The results provide a new method for enhancing the MO effect; the extremely large MO enhancement achieved by our structure has a great potential for use in a wide range of applications.