Enhancement of optical nonlinearity and spontaneous emission in nano-engineered epsilon-near-zero materials

This talk will review our recent studies on the nonlinear and emission properties of conducting oxide and metallic nitride epsilon-near-zero (ENZ) materials. I will present a method to engineer the field intensity enhancement of the Al-doped zinc oxide (AZO) ENZ thin films synthesized by atomic layer deposition (ALD) technique. I will then discuss the observation of abnormal nonlinear temporal dynamic of hot electrons and enhanced optical nonlinearity in AZO and ITO ENZ thin films under different pump fluences and excitation angles using a degenerate pump-probe spectroscopy technique. Finally, I will present the first comprehensive study of photoluminescence from a 2D material placed near ENZ films and its dependence on the losses of materials, as well as the spectral response of such emitters with excitation wavelengths across the ENZ regime. This work was supported in part by the National Science Foundation (grant number: 1752295) and AFOSR-AOARD (FA2386-18-1-4099)