Light emission and absorption is fundamentally a joint property of both an emitter and its optical environment. Nevertheless, because of the much smaller momenta of photons compared with electrons at similar energies, the optical environment typically modifies only the emission/absorption rates, leaving the emitter transition frequencies practically an intrinsic property. We show here that surface polaritons, exemplified by graphene plasmons, but also valid for other types of polariton, enable substantial and tunable control of the transition frequencies of a nearby quantum well, demonstrating a sharp break with the emitter-centric view. Central to this result is the large momenta of surface polaritons that can approach the momenta of electrons and impart a pronounced non-local behaviour to the quantum well. This work facilitates non-vertical optical transitions in solids and empowers ongoing efforts to access such transitions in indirect-bandgap materials, such as silicon, as well as enriching the study of non-locality in photonics.

从根本上说，光的发射和吸收是发射器及其光学环境的共同属性。然而，由于与具有相似能量的电子相比，光子的动量要小得多，因此光学环境通常仅修改发射/吸收速率，实际上使发射器跃迁频率保持固有特性。我们在这里显示出表面极化子，以石墨烯等离激元为例，但也适用于其他类型的极化子，能够对附近量子阱的跃迁频率进行实质性且可调谐的控制，从而证明了以发射器为中心的观点的急剧突破。该结果的中心是表面极化子的大动量，该动量可以接近电子的动量，并赋予量子阱明显的非局部行为。