Fourier analysis of Bloch wave propagation in two-dimensional photonic crystals

摘要

Electromagnetic Bloch waves are the standard representation of the optical field in two-dimensional photonic crystals (2D-PhCs). We present an intuitive description of Bloch waves based on their Fourier transform into series of electromagnetic plane waves. The contribution of each plane wave to the global energy and group velocity is detailed and the valid domain of this decomposition is discussed. This approach enables a continuous description of light propagation from the homogeneous medium to the strongly modulated PhC case and resolves inconsistencies that result from band folding. Finally this model provides a clear physical understanding of the negative refraction effects observed in 2D-PhCs.