Independent Tuning of Exciton and Photon Energies in an Exciton–Polariton Condensate by Proton Implantation‐Induced Interdiffusion.

The use of high energy proton implantation is demonstrated to precisely and independently shift the energies of both exciton and photon components of GaAs microcavity exciton–polaritons. The technique applies post‐growth proton implantation and annealing steps in order to create a small local interdiffusion across either the quantum well–barrier material interfaces, or between the layers of the cavity distributed Bragg reflector mirrors to induce energy shifts to the exciton or photon components, respectively. The polariton mode is tunable by an energy exceeding 10 meV with a corresponding increase (decrease) in effective mass for photon (exciton) energy shifts, while maintaining narrow‐linewidth polariton photoemission and condensation for both photonic and excitonic polaritons. This technique uniquely enables new opportunities to explore coherent polariton matter with narrow‐linewidth and heavy masses in tight‐binding, non‐Hermitian, and topological landscapes with sub‐µm feature‐sizes, while also being a simple post‐growth process. [ABSTRACT FROM AUTHOR]