  Photonic crystals with a sufficiently high refractive index contrast display
partial or full band gaps. However, imperfections in the metamaterial cause
light scattering and extinction of the interfering propagating waves. Positive
as well as negative defect volumes may contribute to this kind of optical
perturbation. In this study, we fabricate and characterize three-dimensional
woodpile photonic crystals, with a pseudo-bandgap for near-infrared optical
wavelengths. By direct laser writing, we intentionally introduce random defects
in the periodic structure. We show that we can model random defect scattering
by considering the difference between the disordered and the regular structure.
Our findings pave the way towards better control and understanding of the role
of defects in photonic materials that will be crucial for their usability in
potential applications.
