Fabrication and optical characterisation of SiO₂opal and SU-8 inverse opal photonic crystals

High-quality photonic crystals of SiO2 spheres and air spheres are fabricated using self-assembling processes and infiltration method with thermal-assistant cell method. Their photonic band structures are characterised by reflectivity spectra measurements. It shows that the tunable optical stop bands are determined by refractive index contrast, diameter of spheres and angle of light illumination. The experimental results of reflectivity spectra agree very well with the results obtained by theoretical Bragg diffraction and photonic band calculations.