2D photonic crystals based on alumina: new methods for formation

Summary form only given, as follows. We present methods developed to form two-dimensional photonic crystals for the visible and near IR spectra. Based on aluminium oxide, the photonic crystals comprise column-like periodic structures of triangular lattice configuration. For a perfect structure, two trends of growth - self-ordered and artificially guided - have to be kept. We propose two prepatterning techniques: (i) using an optical grating, where the relief of the grating is transferred to the surface of aluminium; (ii) interference lithography, a very promising technique. For the second case, the superpositioning of beams with interference patterns of a desired configuration, including flexible change of periodicity, are the main advantages against the grating imprint. The point-like initiation on the aluminium substrate that matches strictly the place of each void, together with successfully adjusted conditions of anodisation, defines the perfect structure. From optical characterisation and calculation, the existence of a photonic band gap in the visible has been confirmed.