Dynamic nanophotonics with conducting oxides and metal nitrides: from all-optical switching to new phenomena

Transparent Conducting Oxides (TCOs) and Transition Metal Nitrides (TMNs) are emerging material platforms for applications in tunable and nonlinear optics such as tailorable/tunable flat optics, all-optical switches and modulators, high harmonic generation as well as novel photonic time crystal concepts and beyond. We report on various approaches to both statically tailor the materials’ properties and dynamically tune the optical response at the ultrafast time scales. We demonstrate remarkable control of the epsilon-near-zero response of TCOs such as aluminum-doped zinc oxide (AZO) and yttrium doped cadmium oxide. We also investigate the strong thickness dependence of the TCOs and TMNs optical properties. Employing the Berreman modes of TiN and AZO films on the same platform, we demonstrate variable switching speeds of an optically pumped metasurface. We also demonstrate the nonlinear capabilities of undoped ZnO for all optical switching and third harmonic generation. To explore the realization of photonic time crystals, we investigate the fastest material response to an optical pump in AZO, showing sub-10 femtosecond rise time. Our approach paves the way to novel phenomena and device design with ultrafast tunable and tailorable materials.