Liquid Crystals for Ultrafast Nonlinear-, Quantum-, and Neuromorphic Computing Optics

Abstract

Liquid crystals possess several highly desirable (often unique) physical attributes. Beyond display screens in ubiquitous devices such as computers, TVs and cell phones, liquid crystals have played an increasing role in a wide range of optical and photonics platforms and bio-chemical sensing devices. This talk focuses on recent grounds breaking developments in the studies of two chiral liquid crystalline materials: cholesteric liquid crystals (CLC) and Blue-Phase liquid crystals (BPLC) that exhibit, respectively, 1-D and 3-D chiral photonic crystals properties. Newly developed fields-guided self-assembly techniques enabled fabrication of CLC with extraordinary dimensions and large areal monocrystalline BPLC with tunable crystalline symmetries. Some examples of novel uncanny abilities of these chiral photonic crystals include ultrafast (ps and fs) pulse laser modulations, and femtosecond switching of complex vector and vortex beams without accessory optics or electronics, as well as efficient entangled photon generation by nonlinear parametric frequency conversion in CLC’s with Ferroelectric constituents. The talk will conclude with a discussion of ongoing work at Penn State on using low-power coherent or incoherent light sources and linear scattering in liquid crystalline cells to perform energy efficient nonlinear neuromorphic optical computing.

Bio

Iam Choon Khoo received his Ph. D. in Physics [theoretical quantum optics] from the University of Rochester. He is currently William E. Leonhard Professor of Electrical Engineering at Penn State. His research interests are in foundational optical physics and nonlinear optics of liquid crystalline materials and reconfigurable micro- and nanostructures, and their applications in switching, compression and stretching of ps and fs pulsed laser, and emergent energy-efficient neuromorphic optical computing paradigms. He has authored/co-author 8 books, 3 patents, 747 publications (302 refereed journals and Proceedings) and given over 440 presentations (with 234 Invited and 36 Keynote/Plenary). He is a Fellow of IEEE, Optica, UK Inst. of Phys., the Electromagnetic Academy, and a member of SPIE. He received several awards at PSU (Outstanding Research; Premier Research; Faculty Scholar Medal for Physical Science and Engineering) and the 2024 SPIE Maria Goeppert Mayer Award in Photonics [https://spie.org/news/iam-choon-khoo-the-2024-spie-maria-goeppert-mayer-award-in-photonics]. His had served a 3-year term as Chair of the US Advisory Committee at the National Academies (NAS and NAE) and as Vice President for Technical Affairs in IEEE-Photonics Society, and a 5-year term as Vice President in the International Commission for Optics. He is the adviser/mentor of 33 Ph. D. graduates, and a committee member of over 65 Ph. D. graduates at PSU, and had served as the external Ph. D. examiner for oversea universities, including: Trinity College (Ireland), Chalmers University (Sweden), Cambridge University (UK), The University of Wollongong (Australia), and Tampere University of Technology (Finland).