광학 메타표면을 통한 다기능적 파면제어: 고해상도 다중컬러 홀로그램 및 이중모드 암호화 디스플레이에 대한 연구

Abstract

Metasurfaces consisting of subwavelength antenna arrays have demonstrated many promising applications such as achromatic focusing, multicolor holography and high-resolution color printing. However, practical use of metasurfaces is still hindered by functional limitations and manufacturing constraints. For example, metasurface-based multicolor holograms suffer from low resolution and irreducible noise. Moreover, the manufacturing of metasurfaces is yet impossible due to high cost and low productivity of conventional metasurface fabrication methods. This dissertation is dedicated to the practical use of optical metasurfaces by establishing novel design principles and developing scalable nanofabrication methods. One of the design principles developed in this work fulfills multicolor holograms by arbitrary dispersion control without any limitations such as low resolution and irreducible noise. Another principle realizes unprecedented optical devices that show colored reflective images under white light illumination, but reveal encoded secret information in the form of hologram under the illumination of coherent light. A low-cost scalable manufacturing method is also developed based on nanoparticle composites, and the experimental demonstration of metasurfaces based on this method confirms that indeed metasurfaces can be manufactured at low cost and high throughput. Considering the bottlenecks to the practical use of metasurfaces, these works will provide real opportunities to commercialize metasurface-based ultrathin optical devices in the future.