February 27, 2009:  Mikael Rechtsman, CIMS

Upper bounds on photonic bandgaps
  

 A 20-year search has been on to find photonic crystals (periodic dielectric structures) with the largest
 possible full photonic bandgaps. A large, robust bandgap is key to the many applications of these materials,
 which include near-lossless waveguiding, optical filtering, optical computing, and others. A number
 of three-dimensional structures with large gaps have been proposed (e.g., a diamond lattice of spheres,
 the "Woodpile" structure), and in two dimensions, structural optimizations to find the largest-bandgap
 structure have been performed. So far, however, there has been no work on
 finding rigorous limits on how high the bandgap may be. In this talk, I present upper bounds on the
 bandgaps of two- and three-dimensional photonic crystals.