Development of a Photonic Switch via Electro-Capillarity-Induced Water Penetration Across a 10-nm Gap

Eui Sang Yu, Kyomin Chae, Taehyun Kim, Jongsu Lee, Jungmok Seo, In Soo Kim, Aram J. Chung, Sin Doo Lee, Yong Sang Ryu

Research output: Contribution to journalArticlepeer-review


With narrow and dense nanoarchitectures increasingly adopted to improve optical functionality, achieving the complete wetting of photonic devices is required when aiming at underwater molecule detection over the water-repellent optical materials. Despite continuous advances in photonic applications, real-time monitoring of nanoscale wetting transitions across nanostructures with 10-nm gaps, the distance at which photonic performance is maximized, remains a chronic hurdle when attempting to quantify the water influx and molecules therein. For this reason, the present study develops a photonic switch that transforms the wetting transition into perceivable color changes using a liquid-permeable Fabry–Perot resonator. Electro-capillary-induced Cassie-to-Wenzel transitions produce an optical memory effect in the photonic switch, as confirmed by surface-energy analysis, simulations, and an experimental demonstration. The results show that controlling the wetting behavior using the proposed photonic switch is a promising strategy for the integration of aqueous media with photonic hotspots in plasmonic nanostructures such as biochemical sensors.

Original languageEnglish
Article number2107060
Issue number14
Publication statusPublished - 2022 Apr 7


  • Fabry–Perot resonators
  • nanogaps
  • refractive index sensors
  • tunable structural color
  • wetting transition

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Chemistry(all)
  • Materials Science(all)


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