物理与光电・能源学部学术报告

报告题目：From Diffractive optical elements to Meta-surface structure

报 告 人:Prof. Yunlong Sheng （Center of Optics, Photonics, and Lasers, Image Science group, Laval University, Quebec, QC, Canada）

报告时间：2014年7月3日（星期四）上午9：30

报告地点：现光所三楼会议室

报告摘要：Recent progress in 3D imaging and 3D display techniques refreshes the interest in research on the holography. For instance, the binary phase holograms fabricated by e-beam lithography and mass replicable are widely used in the holographic projectors for structured illumination for the 3D sensing, robot vision, the Head Mounted Displays (HMDs), the virtual interface display, the gesture and motion sensing in Kinect for Xbox One. The computer generated hologram (CGH) is a matrix of pixels. The e-beam lithography can provide very high definition (50 nm for instance) depending on the e-beam machines. However, the minimum feature size, e.g. minimum distance between two features on the e-beam mask, can be much larger. Therefore, an e-beam CGH should be designed with a very small pixel size (50 nm) although still respecting the minimum feature size constraint. In this way the number of pixels in the CGH and the number of degree of freedom in the design is dramatically increased to several billion pixels. In order to fully explore the very high number of degree of freedom we have proposed the CGH of triangle, polygonal, trapezoidal or orthogonal apertures and several design optimization approaches. An overview on this technique and some recent realizations will be presented in the conference.

In the meta-surface structure the linear nano-antennas play the role of phase modulators for the surface waves in order to realizer different functionalities. I will review the basic optimization algorithms in the CGH design, e. g. the iterative methods, the simulated annealing and the genetic algorithm, which would serve as references and would be useful in the design of meta-surface structures.

报告人简介：Dr. Yunlong Sheng received B.Sc degree in Thermal physics Engineering from the University of Science and Technology of China in 1964, MSc degree in 1980, Doctor degree in Optics in 1982, and ‘State Doctor’ degree in Physics in 1986 in University of Franche-Comté, France. He joints the Center for Optics, Photonics and Lasers (COPL), University Laval Quebec Canada, since 1985 and is now a full professor.

Dr. Y. Sheng’s research interest involves nano-optics, optical trapping, diffractive optics, computer holography, optical wavelet transform, pattern recognition, optical signal processing, aerial imagery object detection and image processing. Dr. Sheng has published more than 250 technical papers in the international journals with referees and in the international conferences, and holds 2 international patents for invention of the complex fiber Bragg gratings (FBG), which became an industrial product for optical fiber communication.  Dr. Y. Sheng’s publications have received more than 4,000 citations with the h-index of 32.

Dr. Yunlong Sheng has been elected as a Fellow of the International Society of Optical Engineering (SPIE) in 1999 and a Fellow of Optical Society of America (OSA) in 2005. He has served as a topical editor for Optics Letters in 2007-2009, an editor for Applied Optics (2014 - ),  a guest editor for the Special issues, “Diffractive Optics” in Optical Engineering in 1999 and “Applications of Nano-optics” for Applied Optics in 2011, “Optical 3D display and imaging” in Chinese Optics Letters in 2014. Dr. Sheng has served also as a conference chair in the biannual Photonics Asia since more than 14 years, and in the biannual conference in Optical Instrumentation Technology (OIT) in 2008 - 2013. Prof. Y. Sheng is pointed as a member of committee of evaluation of the research grant in Physics for the Natural Sciences and Engineering Council (NSERC) of Canada.

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