In situ tunable, room-temperature polariton condensation in individual states of a 1D topological lattice.

Exciton-polariton microcavity arrays have emerged as a promising semiconductor-based platform for analog simulations of model Hamiltonians and topological effects. To study a variety of Hamiltonians and investigate their properties, it is essential to have highly configurable and easily engineerable structures with low disorder. Here, we demonstrate in situ tunable, room-temperature polariton condensation in individual states of a Su-Schrieffer-Heeger topological lattice by using an open-cavity configuration with an organic polymer layer. Changing the cavity length in combination with vibron-mediated relaxation in the polymer allows us to achieve selective polariton condensation into different states of the band structure, unveiled by nonlinear emission, linewidth narrowing, energy blue shift, and extended macroscopic coherence. Furthermore, we engineer the bandgap and the edge state localization by adjusting the interaction between adjacent lattice sites. Our results demonstrate the versatility and accuracy of the platform for the investigation of quantum fluids in complex potential landscapes and topological effects at room temperature.