| The moving of a single quantum-mechanical particle in a periodic lattice under the influence of an external force is of interest for many decades. Particular phenomena in this context are electronic Bloch oscillations and Zener tunnelling, where the probability wave function oscillates and exhibits inter-band tunnelling, respectively. In our presentation, we demonstrate the experimental observation of optical Bloch-Zener dynamics in a waveguide superlattice which show all features of their quantum-mechanical analogs. Using femtosecond laser waveguide writing in combination with special fluorescence imaging we can directly monitor the evolution of the optical wave function. In the regime of single waveguide excitation the double periodicity of the system is discussed and for broad beam excitation the band occupation probability is measured and the tunneling is confined to small spatial zones. |
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