超高圆二色性近红外全介质二维手性超表面

Ultra-high circular all-dielectric near-infrared two-dimensional chiral metasurface

随着微纳加工技术的发展,手性超表面被证明在光学中有着巨大的应用潜力。传统的金属手性结构,由于其自身存在的欧姆损耗,难以取得理想的圆二色性,而具有良好圆二色性但结构复杂的三维手性结构加工制备困难。采用周期性双Si砖错位拼接的二维全介质手性结构,通过激发介质内部中非正交的面内磁偶极矩和电偶极矩,可以产生明显的光学手性响应,从而得到理想的圆二色性。通过仿真优化,该结构在1550 nm波长附近可以实现超过0.94的超高圆二色性,并且可以实现对入射的左旋圆偏振光到右旋圆偏振光的转化。该全介质二维手性超表面的圆二色性高、结构简单、制备难度低,在近红外偏振成像等领域有着广泛的应用前景。

With the development of micro-nano machining technology,the chiral metasurface has been proved to have great application potential in optics.Traditional metal chiral structures are difficult to obtain ideal circular dichroism due to their own ohmic loss,and three-dimensional chiral structures with good circular dichroism but complex structure are difficult to manufacture.The two-dimensional all-dielectric chiral structure of periodic double-Si bricks was adopted.By exciting the non-orthogonal in-plane magnetic dipole moment and electric dipole moment,the optical chiral response could be generated,and the ideal circular dichroism could be obtained.Through simulation optimization,the structure can achieve ultra-high circular dichroism of more than 0.94 at an operating wavelength near 1550 nm,and can realize the conversion of incident left-circularly polarized light to right-circularly polarized light.This all-dielectric two-dimensional chiral metasurface has the advantages of high circular dichroism,simple structure and low preparation difficulty,and has a wide application prospect in the field of near infrared polarization imaging.