Abstract
To fabricate terahertz photonic crystals via a particle assembly technique, sufficient understanding of the effect of particle size dispersity on the photonic band gap may aid the development of new processes and structures. In this study, a combination of experimental and numerical approaches was used to investigate the substantial effect of polydispersity. Polymer-inverted fcc crystals with structural errors were prepared from self-assembled and intentionally polydispersed metal particles. As the polydispersity increased, the band gap reduced and then steeply decreased above a particle size distribution of 4%. Comparison of this experimental spectrum with an analytical spectrum showed that the gap reduction originated due to the displacement of particles from ideal lattice points produced by the polydispersity but not due to the polydispersity itself. This result will aid the development of a new assembly technique for three-dimensional terahertz photonic crystal devices.