Diffractive resonant radiation by spatial solitons in waveguide arrays

Waveguide arrays (WAs) consisting of identical, equally spaced waveguides, present a unique discrete platform to explore many interesting fundamental phenomena such as discrete diffraction [1], discrete solitons [2], and photonic Bloch oscillations [3]. Recently, WAs have also been used to mimic relativistic phenomena typical of quantum field theory, such as Zitterbewegung [4], Klein paradox [5], fermion pair production [6] and the Dirac equation [7].