Abstract
In the last decade, photonic crystals have attracted an increasing interest, mainly because the optical field, i.e., radiation field and light propagation characteristics can be thereby controlled in principle. This is important not only in the basic science such as physics, but also in developing new devices in optoelectronics. For the latter, it is expected, for example, that using a variety of novel unique features of photonic crystals, an extremely-miniaturized planar light circuit will be developed in future. In this review article, the present status of researches in this field is highlighted. First, several pronounced features of two- and three-dimensional photonic crystals are summarized. Second, some aspects of recent development of the crystals are presented with special concern to two-dimensional ones. Third, examples of controlling optical field are presented, which include laser action, enhancement of second-harmonic generation signal, photonic crystal waveguides, and light delay component.
