Microsphere lithography for scalable polycrystalline diamond- based near-infrared photonic crystals fabrication

Wedemonstrate the fabrication of a polycrystalline diamond-based two-dimensional photonic crystal (PhC) slab using microsphere lithography (MSL). First, the essential issues of MSL on rough diamond surfaces are demonstrated. The peak-to-valley value of the rough surfaces is shown as the most important parameter in choosing the appropriate sphere size for the MSL technique. Second, we fabricate a diamond-based PhC composed of a hexagonal lattice of air holes and tuned to have a leaky mode in the near-infrared wavelength region at 1.31 mu m which is an important telecommunication window. A monolayer of plasma-treated polystyrene microspheres with controllable size and periodicity, combined with a metal mask, are utilised as templates in the fabrication process. The prepared diamond films and photonic crystal are characterised using scanning electron microscopy, atomic force microscopy, Raman spectroscopy, reflection, and transmission measurements. In order to investigate the optical properties of the PhC, the experimental measurements are compared with simulation outputs. The successful employment of MSL on rough diamond films with their unique properties opens the road to the large scale fabrication of highly durable and chemically inert scalable structures. (C) 2017 Elsevier Ltd. All rights reserved.