Dielectric metasurfaces for optical field imaging devices,

active optical elements and optimized photonic devices

■ Abstract

Optical dielectric metasurfaces have shown great advances in the last two decades and become promising candidates for next-generation free-space optical elements. In addition to their compatibility with scalable semiconductor fabrication technology, metasurfaces have provided new and efficient ways to manipulate diverse characteristics of light. In this talk, we demonstrate the potential of dielectric metastructures in the realization of compact imaging devices, reconfigurable optical elements, and inverse-designed metasurfaces. With the metasurfaces’ extreme capability to simultaneously control phase and polarization, we first showcase their potential toward optical field imaging applications. In this regard, we demonstrate a system of dielectric metasurfaces and designed random metasurfaces for single-shot phase gradient microscopes and computational complex field imaging system, respectively. Then, we propose nano-electromechanically tunable resonant dielectric metasurfaces as a general platform for active metasurfaces. For example, we demonstrate two different types of the phase and amplitude modulators. While one utilizes resonant eigenmodes in the lattice such as leaky guided mode resonances and bound-states in the continuum modes, the other is based on the high-Q Mie resonances in the dielectric nanostructures where symmetry is broken. In addition to the modulation of the phase and amplitude, we also show tuning of strong chiroptical responses in dielectric chiral metasurfaces. Next, we briefly present our works on new inverse-design methods and experimental demonstrations of inverse-designed multi-layer metasurfaces. Not only do they provide increased degree of freedom in the design space, but also overcome limits of conventional design methods of the metasurfaces.

■ Biography

(1) Educations

- Ph.D. Electrical Engineering, California Institute of Technology, 2016. 9 ~ 2021.6

- Thesis advisor: Professor Andrei Faraon

- Thesis title: Dielectric metasurfaces for integrated imaging devices and active optical elements

- B.S. Electrical and Computer Engineering, Seoul National University, 2016.8

(2) Employments

-Research Scientist, Center for quantum information, Korea Institute of Science and Technology, South, 2022.9 ~ currrent

- Postdoctoral Resarcher at Nanoscale and Quantum Photonics Lab at Stanford (with Prof. Jelena Vučković) (2021.7-2022.8)

■ Contact : 정윤찬 교수(yoonchan@snu.ac.kr)