Photonic crystal waveguides and resonators

Near stop-band edges, periodically microstructured media (photonic crystals) exhibit strong temporal and spatial dispersion, properties which have been used since the late 1970s to design miniature integrated optical components. Towards the end of the 1980s, it was suggested that appropriately designed photonic crystals could display a photonic bandgap, i.e., have no photonic states in at least two dimensions for certain ranges of wavelength. This has caused fresh interest in propagation in periodic media, and is leading to a number of genuinely new applications. This paper looks at this fast-moving direction taken by research on photonic crystals and devices based on them.