Dimensionality effects on the optical diffraction from opal-based photonic structures

We present a comprehensive experimental and theoretical study of visible light diffraction from opal-based photonic structures of different dimensions. We also developed new methodological approaches to collection, processing, and interpretation of experimental diffraction data. The key idea is to analyze the light diffraction data represented in the "incident angle-registration angle" coordinates instead of the widely used "incident angle-registration intensity" coordinates. In such coordinates, a 2D diffraction pattern consists of ovals, while a 3D Bragg diffraction pattern consists of parallel stripes owing to the specular reflection law. Therefore this representation allows one to distinguish easily the patterns originating from 2D diffraction from the ones governed by 3D diffraction. In addition, different types of structural disorder including twinning of the face-centered cubic structure become apparent in the angle coordinates. DOI: 10.1103/PhysRevB.87.125131