Experimental realization of dual-mode Floquet engineering of a chiral ladder in a three-band optical lattice

We report an experimental realization of dual-mode Floquet engineering in a one-dimensional optical lattice using a Bose–Einstein condensate. Through spectroscopic characterization of lattice amplitude and phase modulation, we identify their distinct roles in interband coupling and implement dual-mode driving to realize a Floquet-engineered three-band system. We experimentally confirm the emergence of effective vertical and diagonal interband couplings and demonstrate a pronounced asymmetry governed by the relative phase of the two driving modes, consistent with a chiral ladder description. Furthermore, we demonstrate adiabatic loading of atoms into the engineered Floquet bands and explore the feasibility of geometrical pumping with bosonic atoms. Our results establish experimental benchmarks and practical guidelines for multiband Floquet engineering with bosons, providing a foundation for future realizations of topological pumping in fermionic systems.