Rodrigues Sean P, Lan Shoufeng, Kang Lei, Cui Yonghao, Panuski Patrick W, Wang Shengxiang, Urbas Augustine M, Cai Wenshan
School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Nat Commun. 2017 Feb 27;8:14602. doi: 10.1038/ncomms14602.
Chiral media exhibit optical phenomena that provide distinctive responses from opposite circular polarizations. The disparity between these responses can be optimized by structurally engineering absorptive materials into chiral nanopatterns to form metamaterials that provide gigantic chiroptical resonances. To fully leverage the innate duality of chiral metamaterials for future optical technologies, it is essential to make such chiroptical responses tunable via external means. Here we report an optical metamaterial with tailored chiroptical effects in the nonlinear regime, which exhibits a pronounced shift in its circular dichroism spectrum under a modest level of excitation power. Strong nonlinear optical rotation is observed at key spectral locations, with an intensity-induced change of 14° in the polarization rotation from a metamaterial thickness of less than λ/7. The modulation of chiroptical responses by manipulation of input powers incident on chiral metamaterials offers potential for active optics such as all-optical switching and light modulation.
手性介质呈现出的光学现象会产生与相反圆偏振截然不同的响应。通过将吸收性材料进行结构工程设计成手性纳米图案以形成能提供巨大旋光共振的超材料，可以优化这些响应之间的差异。为了在未来光学技术中充分利用手性超材料固有的双重性，通过外部手段使这种旋光响应可调至关重要。在此，我们报道了一种在非线性 regime 中具有定制旋光效应的光学超材料，它在适度的激发功率下其圆二色光谱会出现明显的偏移。在关键光谱位置观察到强烈的非线性旋光，从超材料厚度小于λ/7 时，偏振旋转的强度诱导变化为 14°。通过操纵入射到手性超材料上的输入功率来调制旋光响应，为诸如全光开关和光调制等有源光学提供了潜力。
