Effects of external electric field upon the photonic band structure in synthetic opal infiltrated with liquid crystal

Based on the electrically controlled birefringence effects of a nematic liquid crystal, a tunable photonic band gap crystal has been fabricated by infiltrating nematic liquid crystal into the voids of synthetic opal composed of silica spheres. A reversible shift of the photonic band gap position and a change of transmittance through the composite opal can be induced by applying an external electric field.