Thesis of Tony Blessant

Defense of thesis Tony Blessant - laboratory PhLAM

Abstract :

The implementation of lattice Hamiltonians in driven–dissipative photonic platforms offers new routes to control transport, localization, and lasing beyond what is accessible in equilibrium solid-state systems. In this thesis, we experimentally and numerically investigate these properties using a hybrid light-matter quasiparticle called exciton–polaritons in semiconductor lattices with non-trivial band structures in the presence of gain, loss and particle interactions. In the first part, we study a one-dimensional chain of coupled micropillars and show that interference between coherent drives and lattice eigenmodes enables phase-controlled directional transport and interference-induced localization. Furthermore, by increasing the pump power, we demonstrate nonlinearity-enabled localization at detunings where the linear system remains only weakly localized. In the second part, we engineer a two-dimensional Lieb sp lattice where the s and p orbital modes of two pillars with different diameters are hybridized to form line-like eigenmodes. Using spatially structured non-resonant pumping, we realize reconfigurable line lasing and show that cross-shaped excitation produces two orthogonal line lasers that lock in energy, phase, and polarization. Finally, we develop a driven–dissipative lattice lasing model that identifies orbital coupling and reservoir-induced blueshift as the minimal ingredients required for this phase locking. Overall, this work highlights polariton lattices as a powerful system for tailoring interference, band structure, and nonlinearity to realize unconventional transport, localization, and lasing phenomena that are difficult to achieve in lattices with trivial band structures.

Keywords : Semiconductor micropillars, Drive and dissipation, Interference, Lieb sp lattice, Orbital line lasing, Cross locking laser