Thin-film optical filters with both functions of incident angle and frequency
空间与频率双性能的薄膜光学滤波器

By coupling two doped one-dimensional photonic crystals, a novel photonic crystal film heterostructure with both functions of frequency and spatial filters is proposed. In a broad frequency range, this optical film filter only transmits light of a selective frequency at normal direction and reflects light of this selective frequency at all other directions; while all other frequencies within the broad frequency range are reflected in any directions.