Photonic crystals display a periodic modulation of the refractive index. For wavelengths that match the Bragg condition, such materials show a photonic band gap. For sufficient refractive index contrast, a complete band gap emerges. That means that the transmission vanishes and incident light is specularly reflected. Interestingly disordered photonic structures are also candidates for complete band gap materials.
For the first time Frank Scheffold and co-workers (University of Fribourg, Switzerland) have realized hyperuniform disordered materials with a broad and pronounced photonic gap in the shortwave infrared. They fabricated silicon replicas of mesoscale polymeric templates which they obtained via direct laser writing. Due to their unique network structure and their high refractive index these fascinating materials are predicted to possess a complete photonic bandgap in the absence of any long-range order. The experimentally observed gap wavelengths are also found in good agreement with the predictions by numerical calculations.
