Recently, a two-layer chiral super surface was proposed in the laboratory of micro optics and photonics, School of Optoelectronics Engineering, Changchun University of Science and Technology. Theoretical and numerical simulation showed that the new surface appeared a new optical chiral breaking phenomenon. The relevant research results are published in the International Journal of the optical bulletin. The first author of the paper is a master's student, Zhao Jianhang, a co - author Professor Liu Zhiying and Professor Zhou Jianhong. The work has been supported by the National Natural Science Foundation Project and the "111" program.
Supermaterials, as an artificial synthetic material with supernormal physical properties, have attracted much attention. As a branch of supermaterials, chiral supermaterials exhibit a lot of supernormal properties. Asymmetric transmission characteristics and polarization by two color conversion development, embodied in the same kind of polarized light from two opposite normal incident, the incident light in one direction because of the cross coupling effect in resonance band and ultra surface enhanced transmission, the transmission light will produce orthogonal polarization cross polarization conversion the resulting incident light. The incident light in the other direction will not be blocked by the cross coupling effect of the super surface. This property can be used for the fabrication of micro polarization control devices, which is one of the hot topics in the study of chiral supermaterials.
At present, most of the studies on asymmetric transmission are focused on how to improve the effect of asymmetric transmission, that is, to study the size of asymmetric coefficients. The group members and introduce another classic effect of material - plasmon electromagnetically induced transparency (plasmonic analogue of electromagnetically induced transparency effect, EIT-like effect), without breaking the structure symmetry, break the asymmetric transmission effect in a particular narrow band, is replaced by symmetric transmission effect the.
The members of this research group added periodic structure nanorods in the double deck chiral super surface which originally showed asymmetric transport effect, and stimulated the coupled bright modes and dark modes in the two layers respectively. For the chiral structure, light mode high loss directly coupled with the incident light, produce asymmetric transmission of a wide passband; nanorods are introduced, due to the near field coupling effect, can stimulate a low loss coupled bright dark mode, mode and dark mode, produce interference effect, inhibition of the chiral field in asymmetric transmission passband generates an optical transparent window of chiral breaking. The wavelength of the chiral breaking window can be regulated freely by changing the length of the nanorods. Because of the high sensitivity of EIT phenomenon to refractive index, the super surface not only provides a new path for the design of biological and chemical sensors, but also introduces the EIT phenomenon into the design of optical polarization control devices.