Interplay of Bloch waves and scattered waves in real photonic crystals

Light propagates inside an ideal and infinite photonic crystal when the Bloch condition is satisfied and any allowed light wave is decomposed in a basis of propagating Bloch waves [1]. In real photonic crystals, light propagation is modified due to unavoidable fabrication-induced structural imperfections in size, positions, and permittivity of the building blocks, as well as the finite size of the crystal. The unavoidable deviations from perfect periodicity result in scattering [2, 3]. Here, we seek to understand the nature of waves inside a real photonic crystal since inevitable disorder plays a significant role in wave propagation.