Gu Guoqiang, Shao Liyang, Song Jun, Qu Junle, Zheng Kai, Shen Xingliang, Peng Zeng, Hu Jie, Chen Xiaolong, Chen Ming, Wu Qiang
Opt Express. 2019 Dec 23;27(26):37771-37780. doi: 10.1364/OE.27.037771.
Recently, a type of curved light beams, photonic hooks (PHs), was theoretically predicted and experimentally observed. The production of photonic hook (PH) is due to the breaking of structural symmetry of a plane-wave illuminated microparticle. Herein, we presented and implemented a new approach of utilizing the symmetry-broken of the microparticles in material composition for the generation of PHs from Janus microcylinders. Finite element method-based numerical simulation and energy flow-represented theoretical analysis were used to investigate the field distribution characteristics and formation mechanism of the PHs. The full width at half-maximum (FWHM) of the PH (∼0.29λ) is smaller than the FWHM of the photonic nanojet (∼0.35λ) formed from a circular microcylinder with the same geometric radius. By changing the refractive index contrasts between upper and lower half-cylinders or rotating the Janus microcylinder relative to the central axis, the shape profiles of the PHs can be efficiently modulated. The tunability of the PHs through simple stretching or compression operations for the Janus microcylinder constituted by one solid inorganic half-cylinder and the other flexible polymer half-cylinder was studied and discussed as well.
最近，一种弯曲光束，即光子钩（PHs），在理论上被预测并通过实验观察到。光子钩（PH）的产生是由于平面波照射的微粒结构对称性的破坏。在此，我们提出并实现了一种利用材料组成中微粒的对称性破坏从Janus微圆柱体产生光子钩的新方法。基于有限元法的数值模拟和以能流表示的理论分析被用于研究光子钩的场分布特性和形成机制。光子钩的半高宽（FWHM）（约0.29λ）小于由具有相同几何半径的圆形微圆柱体形成的光子纳米射流的半高宽（约0.35λ）。通过改变上下半圆柱体之间的折射率对比度或使Janus微圆柱体相对于中心轴旋转，可以有效地调制光子钩的形状轮廓。还研究并讨论了由一个固体无机半圆柱体和另一个柔性聚合物半圆柱体构成的Janus微圆柱体通过简单的拉伸或压缩操作对光子钩的可调性。
