Reflection Properties of Metallic Helical Metamaterials

In the last few years, much attention has been paid to the researches of metallic helical metamaterials due to their giant circular dichroism for transmitted lights. However, so far as we know, there is little work concerning the study of their reflection properties, which are also significant questions for the helical metamaterials. In this work, we study the reflection properties of the helical metamaterials by using the Finite-Difference Time-Domain (FDTD) method. The circular dichroism and the reflected polarization states of left-handed single-, double-, triple-, and quadruple-helical structures are investigated, respectively. It's found that both the single- and the double-helical structures perform giant circular dichroism, and their reflected polarization states are related to the handedness of helical structure; while triple- and quadruple-helical structures exhibit no circular dichroism at all, and their reflected polarization states are irrelevant to the handedness of helical structure.