Optical studies of metal infiltrated opal photonic crystals

N.Eradat
Department of Physics, University of Utah, Salt Lake City, Utah 84112, USA

J.D. Huang, A.Efros, Z.V.Vardeny,
1Department of Physics, University of Utah, Salt Lake City, Utah 84112,
USA
A.A.Zakhidov, R.H.Baughman
Honeywell Int. Research and Technology Center, Morristown, New Jersey
07962-1021,USA

We have studied the optical properties of metal infiltrated opal photonic crystals, and metallic replicas of Bi, Sb, Hg, and Pb. We observed dramatic differences in reflectivity spectrum of the two kinds of metallic structures with network and cermet topologies. All the metallic photonic crystals showed Bragg stop bands in the visible spectral range. Highly interconnected metal structures, however, showed a decrease in the effective plasma frequency of about one order of magnitude. We report an extra peak in the reflectivity spectra of the latter samples related to surface plasmons. We investigate the effect of the lattice constant in position of this peak. Theoretical calculations considering the metallic mesh inside the opal as a cubic wire network agrees with the experimental results. We expect larger light penetration depth for the studied metallic structures due to the smaller plasma frequency in agreement with Coherent Back Scattering measurements showing a much larger optical mean free path for the metal infiltrated opals compared to the skin depth of the metals.


Supported in part by NEDO international funds in Japan.