Preserving Spin States upon Reflection: Linear and Nonlinear Responses of a Chiral Meta-Mirror
Preserving Spin States upon Reflection: Linear and Nonlinear Responses of a Chiral Meta-Mirror
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DOI：
10.1021/acs.nanolett.7b03882
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发表时间：
2017-11-01
期刊：
影响因子：
10.8
通讯作者：
Cai, Wenshan
中科院分区：
文献类型：
--
作者：
Kang, Lei;Rodrigues, Sean P.;Cai, Wenshan
传统的金属反射镜通过反转传播矢量的方向，使正入射的圆偏振波的自旋反转。改变或保持携带数据的光波的自旋状态是满足光子信息处理边缘的关键需求。在这项工作中，我们报道了一种手性超材料反射镜，它强烈吸收一个自旋态的圆极化波，并以保持圆极化的方式反射相反自旋态的圆极化波。在近红外波段，实验观察到反射中的圆二向色响应大到类似于0.5。通过成像由对映体单体组成的合成图案，我们直接看到了我们的工程元镜的两个关键特征，即手性选择性吸收和反射后的偏振保存。在线性区之外，圆极化激发下的手性共振增强了光-物质相互作用，极大地提高了超材料在非线性区进行手性选择性信号产生和光学成像的能力。手性元镜具有巨大的旋光响应和自旋选择性近场增强特性，在极化敏感电光信息处理和生物传感等领域具有广阔的应用前景。
Conventional metallic mirrors flip the spin of a circularly polarized wave upon normal incidence by inverting the direction of the propagation vector. Altering or maintaining the spin state of light waves carrying data is a critical need to be met at the brink of photonic information processing. In this work, we report a chiral metamaterial mirror that strongly absorbs a circularly polarized wave of one spin state and reflects that of the opposite spin in a manner conserving the circular polarization. A circular dichroic response in reflection as large as similar to 0.5 is experimentally observed in a near-infrared wavelength band. By imaging a fabricated pattern composed of the enantiomeric unit cells, we directly visualize the two key features of our engineered meta-mirrors, namely the chiral-selective absorption and the polarization preservation upon reflection. Beyond the linear regime, the chiral resonances enhance light-matter interaction under circularly polarized excitation, greatly boosting the ability of the metamaterial to perform chiral-selective signal generation and optical imaging in the nonlinear regime. Chiral meta-mirrors, exhibiting giant chiroptical responses and spin-selective near-field enhancement, hold great promise for applications in polarization sensitive electro-optical information processing and biosensing.