Diamond-Structured Titania Photonic-Bandgap Crystals from Biological Templates

Photonic crystal scales with a diamond-based lattice from the weevil Lamprocyphus augustus are transformed into a high-dielectric titania replica by a biotemplating double-imprint route. Multidirectional optical reflectance spectroscopy of the replicated structure gives an angle-independent reflection band in the visible spectrum, in agreement with photonic band structure calculations, which reveal the formation of a complete photonic bandgap at visible frequencies.