Nonlinear Physics Center and Laser Physics Center, Center for Ultra-high Bandwidth Devices for Optical Systems, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200, Australia.
Abstract:
We report on the observation of second-harmonic conical waves generated in a novel geometry of the transverse excitation of an annular periodically poled nonlinear photonic structure by a fundamental Gaussian beam. We show that the conical beams are formed as a result of the higher-order nonlinear Bragg diffraction involving two parametric processes in which an ordinary fundamental wave is converted simultaneously into ordinary and extraordinary polarized second harmonics.