Selective confinement of macroscopic long-lifetime exciton and trion populations

Confinement of cold macroscopic particle ensembles opens avenues to study many-body coherent states of matter in a controlled environment. We create pure macroscopic cold long-lifetime trion and exciton gases and arbitrary mixtures spatially confined with fabricated electrostatic potentials on GaAs/AlGaAs coupled quantum well structures. The population densities are readily controlled by electric field and laser power. In the exciton phase, we observe a strong contraction of the exciton mode area at high densities and small traps, indicating the onset of exciton quantum degeneracy, linking and establishing an experimental system in which to study potential macroscopic quantum phases of cold trion gases.