Angular tuning in quasi-phase matched two dimensional nonlinear photonic crystals

We report a numerical demonstration of optical parametric generation with angular tuning in two-dimensional periodically poled lithium tantalate crystals. The purpose is to give interpretation to some experimental results already published, in order to be able to predict similar experimental situations. The aim is to investigate the capabilities of 2D periodically poled crystals for multi-wavelength parametric generation and the general tolerances in terms of tunability and available intensity. We demonstrate that the control of the pump incidence angle may be an efficient way to manage the parametric gain and regulate the generated waves intensity. An original double-circle construction is proposed to explain the angle-dependent quasi-phase matching process.