时间：2013年07月16日上午11：00-12：00
地点：北京大学深圳研究生院G-205
主办方：新材料学院
Title: Fabrication and Characterization for Visible Chiral Metamaterials
报告人: Gao Wensheng,
Physics Department, The Hong Kong University of Science and Technology
Abstract: Metamaterials use artificial structures to achieve gigantically enhanced properties, even non-existed properties than natural materials. Chiral metamaterial is the branch of metamaterials to use chiral structures to enhance chiral-optical effects, even to get non-existed properties such as negative refraction for circularly polarized light. Series study has been made for the chiral metamaterials work in microwave, THz, and IR range. This talk will focus on our investigation on chiral metamaterials work in visible range, including fabrication by multi-step electron beam lithography and characterization by different technique. I will discuss three of our structures to demonstrate the enhancement of optical activity (OA) and circular dichroism(CD); the asymmetric transmission and the environment effects for chiral metamaterials. Complementary double layers of 6-fold gammadions show significant optical activity and circular dichroism, and I will explain the importance for the three dimensional geometry. Double layer metallic cross gratings show more than optical activity and circular dichroism, asymmetric transmission were also observed, the mechanism and application will be discussed. Planar sawtooth metallic gratings with different dielectric environment show the not only the asymmetric transmission but also the environment effect. Above results open new possibilities for further investigation such as optical isolation, chiral molecular sensing et.al.
Biography: Graduate from Wuhan University and Peking University with bachelor and master degree. Completed the PhD degree in the group of Prof Wing Yim Tam at The Hong Kong University of Science and Technology, and followed by two years postdoctoral research in the same university. Interested in fabrication, characterization and develop possible application for metamaterials.
