Nonlinear and electro-optic devices are present in our daily life with many applications: light sources for microsurgery, green laser pointers, or modulators for telecommunication. Most of them use bulk materials such as glass fibres or high-quality crystals, hardly integrable or scalable due to low signal and difficult fabrication. Generating nonlinear or electro-optic effects from materials at the nanoscale can expand the applications to biology and optoelectronics. However, the efficiency of nanostructures is low due to their small volumes.

Here I will show several strategies to enhance optical signals by engineering metal-oxides at the nanoscale with the goal of developing nonlinear and electro-optic photonics devices for a broad spectral range. We use metal-oxides such as barium titanate (BTO) and lithium niobate (LNO) as an alternative platform for nanoscale nonlinear photonics. Recently, we focused on bottom-up assemblies of BTO nanoparticles to obtain electro-optic metasurfaces and quasi phase matching effects (Fig.1).

The field of metal-oxides at the nanoscale has a huge potential of applications in nanophotonics, integrated optics and telecommunication.