Sawtooth lattice in a photonic orbital-angular-momentum simulation system

We construct a full sawtooth lattice model with simulated magnetic and electric fields using orbital angular momentum (OAM) modes in a degenerate optical cavity. In our system, not only can we simulate a large lattice with a theoretically unbound OAM degree of freedom, but it is possible to adjust critical parameters such as the hopping strengths and simulated fields at will by taking advantage of optical interference implemented with simple optical circuit designs based on basic optical elements. Such versatility allows us to prepare appropriate wave packets in the OAM system and investigate their behavior dictated by fundamental physics in the sawtooth model, including Bloch oscillations induced by a driving electric field and Landau-Zener tunneling that arises due to the intricate band structure modulated by the simulated fields. As a first full implementation of the sawtooth model, our results extend photonic OAM quantum simulation significantly by enabling a sophisticated model involving both electric and magnetic fields.