Robustness and fragility of photonic bandgap in photonic amorphous diamond structures

Abstract

The robustness and fragility of the photonic bandgap (PBG) in disordered or modified photonic amorphous diamond (PAD) structures were investigated via numerical calculations. The original PAD has a rod-connected random network structure with a highly ordered local tetrahedral configuration, and it forms a sizable PBG. Our calculations indicated that the PBG of PAD is relatively robust against the introduction of positional disorder that distorts the local tetrahedral configuration, but considerably fragile against the fragmentation of the network structure. PBG formation in a higher frequency region was found in a PAD structure of isolated dielectric spheres. Based on these findings, the physical origin of PBG formation in PADs has been discussed in light of the picture of dielectric and air bands.