Highly birefringent silicon two-dimensional photonic crystals

Summary form only given. Photonic crystals, even those without a complete photonic band gap, possess numerous novel optical properties associated with the polarization, dispersion and anisotropy characteristics of the photonic bands. One such property is birefringence, which is always present for wavelengths comparable to the lattice constant. Although recent experiments have shown moderately large birefringence in this regime, many theoretical studies have shown that photonic crystals may also possess large birefringence in the long-wavelength limit. Here we report measurements of very large birefringence in two-dimensional silicon photonic crystals in the long-wavelength regime, and find excellent agreement with our calculations for these structures.