A. Richel et al., Observation of Bragg reflection in photonic crystals synthesized from air spheres in a titania matrix, APPL PHYS L, 76(14), 2000, pp. 1816-1818
Three-dimensional photonic crystals made of close-packed air spheres in an
interconnected titania matrix have been fabricated using a self-organized t
emplate of polystyrene microspheres of 400 nm diameter. The matrix was obta
ined by vacuum-assisted infiltration of a precursor, with subsequent remova
l of the microspheres by calcination. Electron microscopy has confirmed the
ordering of the structure and the presence of features likely to enlarge t
he photonic band gap. The reflection spectra of the crystal measured at dif
ferent angles of incidence are consistent with Bragg's law and with theoret
ical calculations, confirming the photonic nature of the material. (C) 2000
American Institute of Physics. [S0003-6951(00)04914-7].