Lightshift of Exciton and Exciton-Polarons in a 2D Semiconductor

Monolayer transition metal dichalcogenide (TMD) are direct band gap semiconductors with remarkable optical properties [1]. Due to strong coulomb interaction, they host tightly bound excitons which strongly couple to light. Furthermore, using electrostatic gating, it is possible to dope the material with electrons or holes, which dress the excitons, forming so-called exciton-polarons [2], [3]. A fascinating property of these optical excitations are their enhanced interactions, mediated by the dressing clouds [4], which opens new avenues for quantum optics applications in TMD monolayers.