Dielectric media can exhibit band gaps for light, in direct analogy with electronic band gaps in semiconductors. In electronic systems, such band gaps underpin semiconductor logic and computer technologies, which have driven the digital revolution. In dielectric media, light propagation is governed not only by material composition but also by structure and topology. When the refractive index contrast is sufficiently high and the material is arranged in specific geometries, interference effects emerge on length scales comparable to the wavelength of light, allowing light propagation to be manipulated or suppressed. Controlling light propagation in dielectric media has therefore become a central theme of modern physics, due to its already vast technological applications and its potential for further developments. There are two complementary routes to control light propagation in dielectric media: photonic crystals and amorphous photonic structures.

In this thesis, we present the fabrication, optical, and numerical characterization of both photonic crystals and amorphous photonic structures with photonic properties in the near and mid-infrared regime. We use a state of the art direct laser writing lithography tool and advanced material processing to fabricate photonic materials with different refractive indices. For photonic crystals, we present experimental realizations of Weaire–Phelan foam structures as photonic crystals. We introduce a new method to create photonic materials based on the infiltration of titania into inverse templates. We demonstrate the capability of this method by fabricating a pure titania woodpile PC with a full PBG in the near infrared regime.

We conduct a comprehensive investigation of amorphous photonic structures. We report on the fabrication of three-dimensional, silicon-based amorphous gyroid networks, a novel class of disordered photonic materials based on the concept of local self-uniformity. The optical characterization of these disordered networks is performed using spectroscopic measurements; in particular, we conduct polarization-resolved spectroscopy, which allows us to investigate both ballistic and multiply scattered light components. We show that light transport in these systems cannot be described by classical diffusion theory.