We report on the observation of Zener tunneling of light waves in spectral and time-resolved transmission measurements, performed on an optical superlattice made of porous silicon. The structure was designed to have two photonic minibands, spaced by a narrow frequency gap. A gradient in the refractive index was introduced to create two optical Wannier-Stark ladders and, at a critical value of the optical gradient, tunneling between energy bands was observed in the form of an enhanced transmission peak and a characteristic time dependence of the transmission.
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Here we experimentally demonstrate the dynamics of Bloch-Zener oscillations (BZOs) in a synthetic temporal lattice formed by the optical pulses in coupled fiber loops. By periodically modulating the phases imposed to the optical pulses in linear driven lattices, a two-band Floquet system with tunable bandgaps is realized, and the related BZOs that occurred in this system are displayed. On this basis, by manipulating the phase difference and coupling angle of the synthetic lattice, the widths of 0-gap and -gap are tuned feasibly so that a wide variety of the interplays between Bloch oscillations and Landau-Zener tunneling (LZT) are exhibited.
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