Effects of material parameters on the nonlinear refraction of Transparent Conducting Oxides in the Epsilon-Near-Zero spectral region

Transparent Conducting Oxides (TCOs) exhibit a large and ultrafast nonlinear change of refraction in their Epsilon-Near-Zero (ENZ) spectral region, where the electric permittivity of the material tends to zero. As a result, they have the potential to be used for future applications in high-speed computation and communication in the near-infrared region of the spectrum. However, these materials have the drawbacks of high power consumption and optical loss that need to be addressed before the practical implementation of devices based on them. Therefore, the aim of this thesis is to (i) improve the drawbacks by tailoring the important material parameters of TCOs in the ENZ spectral region and (ii) investigate alternative TCO materials with an improved optical response. In particular, the thesis evaluates the effect of crystal quality on the material parameters and intensity-dependent refraction of TCOs. It also reports, for the first time, the linear and nonlinear optical response of indium-zirconium oxide as a new ENZ-TCO material. These efforts lead to promising results that can contribute to the development of ENZ-TCOs with improved performance to be employed for ENZ-photonic applications.