The modulation to nonlinear Raman-Nath diffraction via manipulating slopes of domain structures

We theoretically report a feasible scheme to modulate nonlinear Raman-Nath diffraction by use of manipulating slopes of domain structures, comprising unitary slope case and consecutive slope case. Our simulations demonstrate that the fulfillment of longitudinal phase matching condition can be achieved effectively in frequency-doubling process. According to particular requirements, each of the two cases in such a scheme could be selected, either obtaining a relatively higher output of average diffraction intensity, or getting a larger tolerance of fundamental wavelength. Furthermore, on account of the modulation, nonlinear diffraction spots possess inversion symmetric diffraction angles but inversion asymmetric intensities along the x-axis, which offers us a potential method to realize phase matching for a specified one order nonlinear diffraction in future.