Luo Kaiwen, Huang Zhijing, Lv Xianpeng, Qiu Wentao, Guan Heyuan, Yang Tiefeng, Grosjean Thierry, Lu Huihui
Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Department of Optoelectronic Engineering, Jinan University Guangzhou 510632 China
School of Electronics and Communication, Guangdong Mechanical and Electrical Polytechnic Guangzhou 510550 China.
Nanoscale Adv. 2023 Feb 6;5(6):1664-1671. doi: 10.1039/d2na00899h. eCollection 2023 Mar 14.
We study the magnetic spin-locking of optical surface waves. Through an angular spectrum approach and numerical simulations, we predict that a spinning magnetic dipole develops a directional coupling of light to transverse electric (TE) polarized Bloch surface waves (BSWs). A high-index nanoparticle as a magnetic dipole and nano-coupler is placed on top of a one-dimensional photonic crystal to couple light into BSWs. Upon circularly polarized illumination, it mimics the spinning magnetic dipole. We find that the helicity of the light impinging on the nano-coupler controls the directionality of emerging BSWs. Furthermore, identical silicon strip waveguides are configured on the two sides of the nano-coupler to confine and guide the BSWs. We achieve a directional nano-routing of BSWs with circularly polarized illumination. Such a directional coupling phenomenon is proved to be solely mediated by the optical magnetic field. This offers opportunities for directional switching and polarization sorting by controlling optical flows in ultra-compact architectures and enables the investigation of the magnetic polarization properties of light.
我们研究了光学表面波的磁自旋锁定。通过角谱方法和数值模拟，我们预测旋转的磁偶极子会产生光与横向电（TE）偏振布洛赫表面波（BSW）的定向耦合。将作为磁偶极子和纳米耦合器的高折射率纳米颗粒放置在一维光子晶体顶部，以将光耦合到BSW中。在圆偏振照明下，它模拟旋转的磁偶极子。我们发现，入射到纳米耦合器上的光的螺旋度控制着出射BSW的方向性。此外，在纳米耦合器两侧配置相同的硅条形波导，以限制和引导BSW。通过圆偏振照明，我们实现了BSW的定向纳米路由。这种定向耦合现象被证明仅由光磁场介导。这为通过在超紧凑结构中控制光流进行定向切换和偏振分选提供了机会，并能够研究光的磁偏振特性。
