近红外波段光学手性可调的非对称纳米圆环研究

Research on Optical Chirality of Asymmetric Nanorings

圆偏振光(CPL)和手性分子具有选择性,可用于实现光学手性分辨.高折射率的金属介电纳米颗粒可以增强这种对映选择性,但不同空间结构的对映选择性会产生几乎为零的空间平均增强.然而,解决这一问题的可行方法是改善纳米结构的圆二色性,增加光学手性密度C和不对称因子g.一个金纳米手性圆环(CR)的超表面被设计,利用FDTD solution软件,其结构在近红外波段展现出较强的圆二色性.通过调节平面手性圆环的3个几何参数,包括内半径r、环宽w、环高h,可以实现该结构的圆二色性在近红外波段的大跨度调控,其圆二色性最大峰值分别达到了0.25以及-0.26左右.

Circularly polarized light(CPL)and chiral molecules exhibit enation-selectivity,which can be used to achieve optical chiral resolution.It has been shown that metal-dielectric nanoparticles with a high refractive index can enhance this enantioselectivity,but the enantioselectivity of different spatial structures will produce a nearly zero spatial average enhancement.However,a feasible solution for this problem is to improve the circular dichroism of nanostructures and to increase the optical chirality density C and Kuhn's dissymmetry factor g.a two-dimensional gold nano chiral ring(CR)surface was designed using FDTD.This monomer structure can exhibit strong circular dichroism(CD).A great enhancement of CD and large spans of wavelength bands can be achieved by altering three geometric parameters of the CR,including the inner radius r,ring width w,and ring height h.At the near-infrared wavelength segment,the peak value of the circular dichroism reached 0.25 and -0.26,respectively.