Flexible tuning of nonlinear non-diffracting array beams using wavelengths and angles.

We present a simple method to enable flexible tuning of non-diffracting beams in a two-dimensional nonlinear photonic crystal, based on the interference of two or more non-collinear second-harmonic beams. By manipulating the wavelengths of the beams and the angle of incidence of the fundamental wave, the arbitrary period and propagation length, as well as the wavelength of the generated nonlinear non-diffracting array beams, can be tuned flexibly. These light beams can trap and manipulate multiple particles, create new forms of optical imaging systems, and act within nonlinear devices to bring novel functionalities to integrated optics.