9632937 Scherer The analogy between electromagnetic wave propagation in multi-dimensional periodic structures, and electron wave propagation in real crystals, have proven to be a very fruitful one. Initial efforts were motivated by the prospect, of a "photonic bandgap"; a frequency band in 3-dimensional dielectric structures, in which electromagnetic waves are forbidden, irrespective of propagation direction in space. These 3-dimensionally periodic dielectric structures are frequently called "photonic crystals". These can be useful in opto-electronics as electromagnetic microcavities for so-called "zero-thresold lasers" and single-mode light emitting diodes. Such structures would exhibit inhibited spontaneous emission, which could lower the power requirements and increase reliability, particularly of optical arrays. Alternately, such structures can show enhanced spontaneous emission which would allow faster modulation speeds for optical interconnects. This renewal grant is funded in parallel with a substantially identical one by Prof. Ely Yablonovich at UCLA. Funding allows continuation of the joint Caltech/UCLA effort to develop the technology for making 3-dimensional photonic crystal structures at the scale of optical wavelengths, and to improve the structural precision and midgap reflectivity of these structures. Such refined photonic crystal structures shculd lend themselves to opto-electronic technology, and they be generically useful in optical science. ***
