Liquid crystalline photonic crystals for ultrafast (linear and nonlinear) photonics

Dr. Iam-Choon Khoo

The Pennsylvania State University

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Abstract

Bulk/crystalline reorientation by an external field resulting in changes in the optical properties of the liquid crystals and trigger the desired operations such as polarization switching and control in ubiquitous devices such as cell phones, TV and computer display panels employ to effect. These processes are characterized by response times in the milliseconds to microseconds time sales and the fundamental optical physics underlying these processes are now quite well understood. In this talk, I will focus on the relatively less-explored electronic ultrafast [ps and fs] response of LC molecules to an optical fields and unravel some myths about liquid crystals in general, and revealed the uncanny abilities of liquid crystals to modulate ultrafast laser pulses in particular. Owing to the unique combination of photonic crystal and liquid crystalline properties, the performance characteristics of LC photonic crystals in the ultrafast time scales rival most state-of-the-art materials used for such operations, including all optical self-compression/stretching and polarization switching of optical vector fields of common (linear, elliptical) or complex (azimuthal, radial) polarization states New theoretical insights into nonlinear optical processes of the liquid crystals as well as the optical fields will be presented along with experimental confirmations with ps/fs laser pulses.

About the speaker

Dr. Iam Choon Khoo received his Ph. D. in Physics [Quantum Optics] from the University of Rochester in 1976.. He is currently the W. E. Leonhard Professor of Electrical Engineering at the Pennsylvania State University. He is a Life Fellow of IEEE, and Fellow of The Optical Society (OSA), UK Institute of Physics and The Electromagnetic Academy. He has previously served a three-year term as Chair of the United States Advisory Committee/International Commission for Optics [US National Academies (Sciences and Engineering)] and also Vice President of Technical Affair [IEEE Photonic Society. He is the author, co-author of ~ 300 technical publications, and several books on liquid crystal optical physics and nonlinear optics. Among the dozens of international conference he has chaired/co-chair, he is the initiator/organizer/char of the first Nonlinear Optics Conference (Hawaii, 1990) and Chair of the yearly Liquid Crystal Conference (San Diego) since 1995. He has served as the External Ph. D. Examiner – Trinity College (Physics), Dublin, Ireland (2001); Chalmers University (Physics), Sweden (2002); Cambridge University (Electrical Engineering), UK (2005); The University of Wollongong, (School of Mathematics and Applied Statistics) Australia (2013) and Tampere University of Technology (Physics/Photonics), Finland (2018). [https://sites.psu.edu/eekhoo/dr-iam-choon-khoo/]

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