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IEEE AP/MTT – Dr. Chengjun Zou – Electrically tunable dielectric metasurfaces facilitated by the photoalignment of liquid crystals
November 30, 2018 @ 10:00 am - 11:00 am
Optical metasurfaces based on dielectric resonators have established as an efficient platform for realizing a multitude of optical functionalities. Recently, tunable optical dielectric metasurfaces have attracted increased research interest, and various tunable dielectric metadevices have been demonstrated. Infiltrating dielectric metasurfaces with nematic liquid crystals (LCs) represents an efficient and convenient tuning approach, which is compatible with established LC industrial technologies. Here we demonstrate two electrically tunable LC-infiltrated dielectric metasurfaces working at near-infrared and visible wavelengths, respectively. For the first time to our knowledge, we have utilized a LC photoalignment material to realize LC-tunable metasurface devices with drastic improvement of their tuning performance and reproducibility. We demonstrate that the metasurfaces can be electrically tuned into and out of the so-called Huygens’ regime of spectrally overlapping electric and magnetic dipolar resonances by application of an external voltage, achieving a modulation depth of over 70% at 1070 nm. Furthermore, we demonstrate a switchable silicon transmissive display with 53% contrast, operating in the visible spectral range. As an outlook, we explore phase-only tuning by applying simultaneous electrical and thermal stimuli to the LC-infiltrated dielectric Huygens’ metasurfaces.
Dr. Chengjun Zou received his Ph.D in Engineering from The University of Adelaide in 2017 supported by the Adelaide Graduate Research Scholarship. From July to November 2016, he was a visiting researcher at RMIT University funded by the Australian Nanotechnology Network. Since April 2017, he works as a postdoctoral researcher on tunable optical dielectric metasurfaces at Abbe Center of Photonics, Friedrich Schiller University Jena, Germany. He received the 2017 Gertrude Rohan memorial prize from The University of Adelaide and the 2018 E. Altschuler AP-S Magazine Prize Paper Award from the IEEE Antennas and Propagation Society.