Journal article

High-quality photonic crystals with a nearly complete band gap obtained by direct inversion of woodpile templates with titanium dioxide

  • Marichy, Catherine Department of Physics, University of Fribourg, Switzerland - Laboratoire des Multimatériaux et Interfaces - UMR 5615 CNRS / UCBL, Université Claude Bernard Lyon, France
  • Muller, Nicolas Department of Physics, University of Fribourg, Switzerland
  • Froufe-Pérez, Luis S. Department of Physics, University of Fribourg, Switzerland
  • Scheffold, Frank Department of Physics, University of Fribourg, Switzerland
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Published in:
  • Scientific Reports. - 2016, vol. 6, p. 21818
English Photonic crystal materials are based on a periodic modulation of the dielectric constant on length scales comparable to the wavelength of light. These materials can exhibit photonic band gaps; frequency regions for which the propagation of electromagnetic radiation is forbidden due to the depletion of the density of states. In order to exhibit a full band gap, 3D PCs must present a threshold refractive index contrast that depends on the crystal structure. In the case of the so-called woodpile photonic crystals this threshold is comparably low, approximately 1.9 for the direct structure. Therefore direct or inverted woodpiles made of high refractive index materials like silicon, germanium or titanium dioxide are sought after. Here we show that, by combining multiphoton lithography and atomic layer deposition, we can achieve a direct inversion of polymer templates into TiO₂ based photonic crystals. The obtained structures show remarkable optical properties in the near-infrared region with almost perfect specular reflectance, a transmission dip close to the detection limit and a Bragg length comparable to the lattice constant.
Faculté des sciences et de médecine
Département de Physique
  • English
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