Optically engineered nonlinear photonic structures in ferroelectrics

Performance of many optical devices based on frequency conversion critically depends on spatial modulation of the nonlinear optical response of the materials. This modulation ensures, via the quasi phase matching (QPM)¹, an efficient energy exchange between optical waves at different frequencies. The QPM structures, also known as the nonlinear photonic crystals², offer a variety of novel properties and functionalities that cannot be obtained in uniform nonlinear crystals³. Typically, such nonlinear structures have been fabricated via electric-poling. However, this technique is restricted to particular crystallographic geometries, and does not allow to create isolated structures inside the nonlinear material. This means that one cannot realize fully 3-dimensional nonlinear structures via traditional electrical poling.