New route to three-dimensional photonic bandgap materials:: Silicon double inversion of polymer templates

High-refractive-index, 3D photonic crystals (see Figure) are produced by silicon double inversion of a polymer woodpile template fabricated by multiphoton direct laser writing. The method incorporates silica chemical vapor deposition fine-tuning of the filling fraction of an intermediate silica inverted woodpile, and thus the ability to tailor the width of the complete photonic band gap of the silicon woodpile.