Surface-emitting laser designs based on one- and two-dimensional photonic crystals

Summary form only given. We propose a class of laser designs based on 1D and 2D photonic crystals (PCs), which result in surface emitting lasers with a fabrication process similar to that used in edge-emitting DFB feedback lasers. The basic principle employed is based on our recent discovery that the output coupling characteristics of 2D gratings (or PCs) are significantly different from 1D gratings. In 2D PCs, phase-matching conditions result in the coupling of light to one or a discrete number of directions instead of a cylindrical wave. We have designed numerous combinations of lasers and couplers, which have the potential to couple to a single spot normal to the plane of the waveguide. The lasers are experimentally realized with organic semiconductors and involve photoexcitation of patterned combinations of organic semiconductor and dielectrics. The patterning is accomplished by advanced optical or electron-beam lithography followed by dry etching and the subsequent deposition of the organic gain medium as a thin coating. One design that has been successfully implemented is a square 2D PC, which functions as a laser and output coupler. We have investigated the physics of 2D photonic crystal lasers and find that they may be useful for high-power lasers. We have experimentally realized such lasers with lattices possessing square, triangular, and honeycomb symmetries. However, for many applications, conventional 1D lasers are quite sufficient. A potentially promising design ensconces a 2D photonic crystal within a set of 1D gratings. For a square PC four 1D gratings are required. The 2D PC can then act as an output coupler/mixer for 1D lasers. In this manner, it is possible to create a compact surface-emitting laser combining the advantages of 1D DFB lasers and 2D photonic crystal couplers.