Patterning and pixelation of colloidal photonic crystals for addressable integrated photonics

Abstract

Patterning colloidal photonic crystals are a first step to the realization of integrated photonic circuits. In this paper, we introduce a new way to pattern colloidal photonic crystals by applying ultrasonication to selectively remove certain parts of the colloidal photonic crystal film from the substrate. These patterns with hydrophobicity can further function as templates to direct the growth of another layer of colloidal photonic crystal in order to reach dual-patterned photonic crystals with distinct hydrophilic and hydrophobic domains. The dual-patterns are responsive to water vapor, which can reversibly switch the reflection color of the hydrophilic regions on and off many times, while the hydrophobic parts are almost unaffected.