논문 해외 국제전문학술지(SCI급) Self-assembled nano–lotus pod metasurface for light trapping
- 학술지 구분 국제전문학술지(SCI급)
- 게재년월 2021-05
- 저자명 Nayeun Lee, Reehyang Kim, Ju Young Kim, Jong Beom Ko, Sang-Hee Ko Park, Sang Ouk Kim, Mark L Brongersma, Jonghwa Shin
- 학술지명 ACS Photonics
- 발행처명 American Chemical Society
- 발행국가 해외
- 논문언어 외국어
- 전체저자수 8
- 원문 링크 https://doi.org/10.1021/acsphotonics.0c01882
홈페이지논문 초록 (Abstract)
Concentration of electromagnetic waves in deep-subwavelength volumes has been widely investigated as a direct way of enhancing light-matter interactions. However, a homogeneous array of subwavelength nanogaps suitable for visible light localization and enhancement is difficult to realize due to the limitations of conventional lithography techniques. Here, a uniform array of ultrasmall plasmonic resonators with precisely controlled nanogaps (“nano–lotus pods”) is presented for the visible light confinement and realized without any photo- or beam-based lithography steps. The unit motif of this metasurface with a physical volume of 52 × 60 × 40 nm3 is designed to resonantly trap visible light into an effective mode volume of 1.57 × 10–5λ03. Each nano–lotus pod can be considered as a curved metal–insulator–metal waveguide which exposes both of its end faces and thus hot spots with the strongest electric fields on the outermost flat surface. To realize this unique nanostructure, a template-stripping method is employed in conjunction with block copolymer self-assembly and atomic layer deposition which guarantee a homogeneous array over large areas. It is experimentally demonstrated that the proposed metasurface can be used as a highly uniform and flat substrate for surface-enhanced Raman spectroscopy of various analytes, especially a stiff two-dimensional material.