SAMOP 2023 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 13: Ultra-cold Atoms, Ions and BEC I (joint session A/Q)
Q 13.1: Hauptvortrag
Montag, 6. März 2023, 17:00–17:30, F303
Multi-frequency optical lattice for dynamic lattice-geometry control — Marcel Kosch1, •Luca Asteria1,2, Henrik Zahn1, Klaus Sengstock1,2,3, and Christof Weitenberg1,2 — 1Institut für Laserphysik, Hamburg University — 2The Hamburg Centre for Ultrafast Imaging — 3Zentrum für Optische Quantentechnologien, Hamburg
Ultracold atoms in optical lattices are pristine model systems with a tunability and flexibility that goes beyond solid-state analogies. However, a fast change of the lattice geometry remains intrinsically difficult. Here we introduce a multi-frequency lattice for fast and flexible lattice-geometry control and demonstrate it for a three-beam lattice, realizing the full dynamical tunability between honeycomb lattice, boron-nitride lattice and triangular lattice on the microsecond scale, i.e., fast compared to the relevant energy scales. At the same time, the scheme ensures intrinsically high stability of the lattice geometry. We introduce the concept of a geometry phase as the parameter that fully controls the geometry and observe its signature as a staggered flux in a momentum space lattice. Tuning the geometry phase allows to dynamically control the sublattice offset in the boron-nitride lattice. We use a fast sweep of the offset to transfer atoms into higher Bloch bands, and perform a new type of Bloch band spectroscopy by modulating the sublattice offset. Finally, we generalize the geometry phase concept and the multi-frequency lattice to 3D optical lattices and quasi-periodic potentials. This scheme will allow novel Floquet and quench protocols to create and probe, e.g., topological properties.