Solution‐Processed Barium Titanate Nonlinear Woodpile Photonic Structures with Large Surface Areas

Most of the current top-down fabrication approaches for 3D nonlinear photonic crystals are time consuming, costly and limited to small surface areas. In article number 1900755, Viola V. Vogler-Neuling et al. present a promising solution to these challenges. 3D nonlinear woodpile photonic crystals made by solution processing of barium titanate nanoparticles and UV-soft nanoimprint lithography are fabricated, resulting in large surface areas of 1 cm2. Diffraction patterns and nonlinear polar measurements show the cubic photonic crystal structure of the woodpile assembly. With barium titanate's electro-optic, elasto-optic and thermo-optic properties, active nonlinear photonic crystals could be realized in the future.