Near-atomically flat, chemically homogeneous, electrically conductive optical metasurface. Issue 19 (7th May 2019)

• Record Type: Journal Article
• Authors: Kim, Jong Uk; Jeon, Suwan; Heo, Minsung; Kim, Hwi-Min; Kim, Reehyang; Kim, Nayoung; Lee, Yong-Hee; Shin, Jonghwa
• Is Part Of: Nanoscale. Volume 11:Issue 19(2019)
• Page Start: 9580
• Page End: 9586
• Publication Date: 2019-05-07
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c8nr10436k
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Near atomically flat, chemically homogeneous, and electrically conductive surfaces with hidden dielectric cavities functioning as new type of optical metasurfaces. Abstract : Metasurfaces, or two-dimensional arrays of subwavelength-scale structures, can exhibit extraordinary optical properties. However, typical metasurfaces have a bumpy surface morphology that may restrict their practical applications. Here, we propose and demonstrate an optical metasurface that is composed of a thin metallic film, with hidden dielectric structures underneath, and a metal back mirror layer. Exploiting the large difference between the Thomas–Fermi screening length for longitudinal electric fields and the skin depth for transverse electromagnetic fields, the near-atomically flat top surface of the proposed structure can appear homogeneous chemically and electrically but highly inhomogenous optically. The size and shape of the hidden dielectric structures as well as the thickness of the top metallic layer can be tailored to acquire desired optical properties. We performed both theoretical and experimental studies of the proposed metasurface, finding a good agreement between them. This work provides a new platform for ultra-flat optical devices, such as a wavelength selective electrode, diffusive back reflector, meta-lens, and plasmonically enhanced optical biosensors.