Physics and Astronomy Colloquium

           Tuesday, February 13, 2001, 4:10 pm 
           Room 118 Physics-Astronomy Building
           Refreshments at 3:45 pm in Room 224


      COLLOIDAL SELF-ASSEMBLY AND PHOTONIC CRYSTALS

      Pierre Wiltzius, Bell Labs

Colloids have the interesting property of self-assembling into 
3-dimensional periodic structures. These colloidal crystals can 
be made from suspensions of monodisperse, low-index of refraction 
(n ~ 1.5) silica or polystyrene spheres. If the lattice constants 
of the crystals are comparable to the wavelength of visible or 
near-infrared light they act like three-dimensional gratings. I will 
review our progress towards making photonic band gap structures and 
switchable gratings by introducing high-dielectric constant materials 
and liquid crystals into the microperiodic assemblies.