Angle- and spectrally-resolved Bragg scattering on two-dimensional silicon-based photonic crystals

Georg von Freymann1, •Wolfpeter Koch2, Martin Wegener1,2, Marcus Diem3, Antonio Garcia-Martin3, Surresh Pereira3, Kurt Busch3, Jörg Schilling4, Ralf B. Wehrspohn4 und Ulrich Gösele4
1Institut für Nanotechnologie, Forschungszentrum Karlsruhe, 76021 Karlsruhe
2Institut für Angewandte Physik, Universität Karlsruhe (TH), 76128 Karlsruhe
3Institut für Theorie der Kondensierten Materie, Universität Karlsruhe (TH), 76128 Karlsruhe
4Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle

We show that the envelope of the diffraction efficiency of a two-dimensional silicon photonic crystal can exhibit spectral regions of very small diffraction efficiency ( 10-4), while in other regions, the diffraction efficiency is near unity. In the experiment, light from a halogen lamp is coupled into a balanced Michelson interferometer. At the end mirrors, one of which is replaced by the photonic crystal, the light is focused to a spot diameter of about 100 mm, which illuminates the entire height of the sample. The spectrum is obtained from the Fourier transform of the interferogram. The experimental results on hexagonal, silicon-based photonic crystals agree qualitatively with corresponding numerical calculations. Furthermore, we point out the crucial influence of the surface termination for reflection experiments and speculate about possible applications of such additional spectral filters in Raman and photoluminescence spectroscopy.