Fabrication and characterization of silicon woodpile photonic crystals with a complete bandgap at telecom wavelengths.

By using direct laser writing into a novel commercially available photoresist and a silicon-double-inversion procedure followed by tempering of the silicon structures, we realize high-quality centered-tetragonal woodpile photonic crystals with complete photonic bandgaps near 1.55 microm wavelength. The 6.9% gap-to-midgap ratio bandgap is evidenced by the comparison of measured transmittance and reflectance spectra with band-structure and scattering-matrix calculations.