Conceptual

Wavenumber-Evolution Laws for Bloch-Zener Oscillations in Binary Waveguide Arrays

A wavenumber-based analytical treatment of Bloch-Zener oscillations of light in binary waveguide arrays. Two simple laws describe how a beam's central wavenumber evolves along the propagation direction under a linear index gradient. From them one obtains closed-form propagation distances where the beam sits at the Dirac points (so interband Zener tunneling occurs) and where it reaches the turning points of its Bloch oscillation; these distances depend only on the linear-potential strength and the input beam's initial wavenumber. The analysis also shows Kerr nonlinearity degrades the oscillations, giving a compact predictive picture of when tunneling and turning happen in such photonic lattices.