Creating bio-inspired hierarchical 3D-2D photonic stacks via planar lithography on self-assembled inverse opals

TL;DR

This paper introduces methods to create bio-inspired hierarchical 3D-2D photonic stacks by combining planar lithography and self-assembled inverse opals, enabling complex architectures similar to butterfly wing scales.

Contribution

It develops two novel techniques to deposit patterned planar layers on inverse-opal photonic crystals, merging top-down and bottom-up fabrication for advanced photonic structures.

Findings

Successfully fabricated hierarchical structures resembling butterfly wings.

Demonstrated controllable patterning on 3D photonic crystals.

Potential applications in omnidirectional coloration and photonic devices.

Abstract

Structural hierarchy and complex 3D architecture are characteristics of biological photonic designs that are challenging to reproduce in synthetic materials. Top-down lithography allows for designer patterning of arbitrary shapes, but is largely restricted to planar 2D structures. Self-assembly techniques facilitate easy fabrication of 3D photonic crystals, but controllable defect-integration is difficult. In this paper we combine the advantages of top-down and bottom-up fabrication, developing two techniques to deposit 2D-lithographically-patterned planar layers on top of or in between inverse-opal 3D photonic crystals and creating hierarchical structures that resemble the architecture of the bright green wing scales of the butterfly, Parides sesostris. These fabrication procedures, combining advantages of both top-down and bottom-up fabrication, may prove useful in the development of omnidirectional coloration elements and 3D-2D photonic crystal devices.