Optical Bloch Oscillations of a Dual Airy Beam

We investigate the propagation of a dual Airy beam in Hermitian and non-Hermitian waveguides, theoretically and numerically. Optical Bloch oscillations (OBOs) of the beam are demonstrated during propagation in both types of waveguides, and the numerical OBO period is found to be in accordance with the theoretical predictions. The two branches of the dual Airy beam do not display translational symmetry — the peaks will form in one branch only, due to the desynchronized Bragg reflection of the lobes. In the non-Hermitian waveguides, the dual Airy beam will be damped or amplified during propagation — depending on the imaginary part of the complex potential, which may provide loss or gain to the beam. In the PT-symmetric-like potential, the dual Airy beam may undergo amplification during propagation, but the total power will exhibit a stair-like behavior. The non-reciprocity is also exhibited by the dual Airy beam in such a potential. We believe that our research not only provides a new geometry for optical switches but also deepens the understanding of OBO in dual Airy beams.