Semiconductor 2D and 3D photonic crystals

Summary form only given. Much interest has been drawing in photonic crystals in which the refractive index changes periodically. A photonic bandgap is formed in the crystals, and the propagation of electromagnetic waves is prohibited for all wave vectors. Various important scientific and engineering applications such as control of spontaneous emission, zero-threshold lasing, very sharp bending of light, and so on, are expected with the photonic bandgap and the artificially introduced defect states and/or light-emitters. In this presentation, the present status of semiconductor 3D and 2D photonic crystals is reviewed. For 3D photonic crystals, the development of complete photonic: crystals at optical wavelengths and the applications to ultrasmall optical circuits have been demonstrated. On the 2D photonic crystals, a coherent lasing action due to coupling of six equivalent light-waves, and a trapping and emission of photons by single defect have been demonstrated.