Propagation of light beams along line defects formed in a-Si/SiO2 three-dimensional photonic crystals: Fabrication and observation

Abstract

We have fabricatedoptical waveguides in three-dimensional (3D) photonic crystals and observed propagation of light beams. Light beams with wavelengths of 1.15 μm propagate along the line defects formed in the 3D photonic crystals. The 3D photonic crystals consist of a- Si/SiO 2 multilayers laminated alternately by rf bias sputtering on a periodically hollowed silica substrate with a triangular lattice. The pit diameter is 0.2 μm and the pitch of the lattice is 0.5 μm. The thickness of each laminated layer is 0.2 μm. Line defects are formed normal to the surface by laminating a- Si/SiO 2 multilayers with ten periods on the substrate in which the corrugation patterns have been omitted in a certain area corresponding to the core. The measurements of transmittance normal to the surface show that the wavelength of 1.15 μm used in observation of propagation is in the passband for the one-dimensional periodic region corresponding to the core and in the stop band for the 3D periodic region corresponding to the cladding, respectively. Measurements show good agreement with finite-difference time-domain calculations.