The Chiral Metamaterial and Its Strong Optical Activity and Negative Refractive Index

The basic principle of negative refractive index in chiral metamaterial is introduced.The structure models of several chiral metamaterials are described.The research advances of the optical activity,circular dichroism and negative refractive index for the chiral metamaterials in microwave region,infrared and visible light region are reviewed.The problems of losses and homogeneity in the chiral metamaterials are pointed out.