Transmission characterization of drilled alternating-layer three-dimensional photonic crystals

To investigate the photonic band structure of a drilled alternating-layer photonic crystal (DALPC), light transmittances were measured. Electron beam lithography was used to prepare $\mathrm{Si}/{\mathrm{SiO}}_2/\mathrm{air}$ DALPCs that had four periods in the $z$ direction with air holes penetrating the whole structure. The transmittances of TE/TM polarized lights were measured for three directions $\mathrm{(\Gamma –X,}$ $\mathrm{\Gamma –Y,}$ $\mathrm{\Gamma –Z).}$ There was a common transmittance attenuated band at a wavelength of around 1.4 μm in the transmission spectra for all measured directions and polarizations. This agreed well with the photonic band gap (PBG) predicted by calculation. The results supported the good potential of Si-based DALPCs as full PBG materials.