Diffraction efficiency and guided light control by two-dimensionalphotonic-bandgap lattices

摘要

We report on the measurement of the diffraction efficiency ofntwo-dimensional photonic-bandgap lattices consisting of a triangularnarray of circular air holes etched in a semiconductor waveguide. We usenthe spontaneous emission of the material as an internal point source.nCombined with previous reflectivity and transmission measurements, thendiffraction data allow us to assess the total amount of out-of-planenlosses experienced by a guided wave traversing the dielectric lattice,nas a function of the lattice pitch. We found that these losses arenparticularly weak for some range of parameters, especially in thenphotonic bandgap of interest. We discuss the reasons why they can bensubstantial with other parameters