题　目：Shaping focus beyond the diffraction limit with complex fields
报告人：Prof. Qiwen Zhan（美国戴顿大学）
时　间：7月3日（周五），上午10：00
地　点：物理馆512会议室
Abstract:
Recently there is an increasing interest in complex optical fields with spatially variant amplitude, phase and/or polarization within the beam cross-section. Scalar optical vortices carrying orbital angular momentum and vectorial vortices such as radially, azimuthally polarized beams are among the most intensively studied examples. The added degrees of freedom arising from the amplitude, phase and polarization diversity within the beam cross-section enables scientists and engineers to break the limits imposed by conventional wisdom in many applications. In this talk I will give brief introduction of the fundamentals of various complex optical fields and their methods of generation. Systematic approaches using these complex fields for comprehensive three-dimensional focal field engineering are reviewed and exotic optical focal field distributions beyond the diffraction limit are demonstrated as examples. Field manipulation, focusing and confinement through the interactions of these complex fields with nanostructured materials and surfaces and their applications will also be presented.
Brief Bio:
Dr. Qiwen Zhan is Professor of Electro-Optics and Electrical & Computer Engineering, Director of the Nano Electro-Optics Laboratories, and Managing Director of the Fraunhofer Research Center at the University of Dayton. He received BS in physics from the University of Science and Technology of China in 1996 and Ph.D. in Electrical Engineering from the University of Minnesota in 2002. Prof. Zhan’s research has attracted more than $4M as PI and more than $7M as co-PI. He has published 1 book, 7 book chapters, more than 150 journal and conference publications, delivered many conference presentations and invited talks/lectures/seminars, and possessed 6 US patents/patent applications. Dr. Zhan is a Topical Editor for Applied Optics, Guest Editor for Optics Express, Special Symposium Chair of CLEO and Chair of the Polarization Technical Group of the OSA. Prof. Zhan is elected Fellow of the OSA and Fellow of the SPIE. He is also a senior member of the IEEE, IEEE Photonics Society and a member of the AAAS.