I. C. Khoo
Pennsylvania State University
地点：唐仲英楼B501
时间：2015-09-18 10:00
A critical analysis of various all major mechanisms for optical nonlinearities of nematic as well as Blue-Phase liquid crystals is presented, along with feasibility demonstrations of femtoseconds pulse compression, all-optical switching with nanoseconds – CW laser and tuning/modulations of micro- or nano-photonic structures [1-3]. Specifically, we will delve into individual molecular electronic nonlinearities with femtoseconds [4] response speed as well as slower (nanoseconds – milliseconds) collective molecular responses such as laser induced crystalline axis rotation, reorientation and lattice distortion. The merits and limitation of nematics are discussed together with some recent results with Blue Phase liquid crystals that could circumvent some of the limitations.
Dr. Khoo is internationally known for his pioneering and leading work in liquid crystals, and in nonlinear optical phenomena and applications. He has been a faculty member at Penn State since 1984, where he has established and directed the Nonlinear Optics and Liquid Crystal Research Laboratory. Over the years, his laboratory has received research funding from various Government agencies including:- the National Science Foundation, Defense Advanced Research Projects Agency, Navy Air Development, Air Force Office of Scientific Research, Air Force Phillips Laboratory, and the Army Research Office. Prof. Khoo is a Fellow of the Optical Society of America, IEEE, The United Kingdom Institute of Physics and The Electromagnetic Academy. He has previously served a three-year term as Vice President of Technical Affair for the IEEE-Lasers and Electro-Optics Society and as Chair of the United States Advisory Committee/International Commission for Optics of the US National Academies. He is the author, co-author of over 600 technical publications and several books on nonlinear optics and liquid crystal optical physics. Ongoing research activities in his laboratory and collaborative research programs are centered on nonlinear and electro- optical properties of liquid crystals and nano-structured novel refractive metamaterials, and studies of optical wave mixings, optical switching and modulation, optical limiting and sensor protection enabled by unique properties of these optical materials.