Enhanced circular dichroism based on the dual-chiral metamaterial in terahertz regime**Project supported by the National Natural Science Foundation of China (Grant Nos. 11174051, 11374049, and 11204139), the Natural Science Foundation of Jiangsu Province of China (Grant No. BK20131283), and the Fundamental Research Funds for the Central Universities, China.

Abstract

The obvious circular dichroism (CD) and optical activity can be obtained based on the chiral metamaterial due to the plasmon-enhanced effect, which is very attractive for future compact devices with enhanced capabilities of light manipulation. In this paper, we propose a dual-chiral metamaterial composed of bilayer asymmetric split ring resonators (ASRR) that are in mirror-symmetry shape. It is demonstrated that the CD can get enhancement in the terahertz regime. Moreover, the CD can be further improved by modulating the asymmetry of ASRR. The enhanced CD effect in the terahertz regime has great potential applications in sensing, biomedical imaging, and molecular recognition.