Nonlocal Switch and Transistor between Single Photons

Harnessing the spatial degree of freedom of single photons is crucial for studying quantum optics and developing new optical devices. However, photons in distinct spatial modes do not interfere, making it challenging to induce interactions between them. As a result, realizing quantum operations among photons in different modes remains very challenging. Here, we demonstrate a novel approach leveraging orbital angular momentum (OAM) photons and Rydberg atoms to realize nonlocal quantum optical devices. By coupling OAM light modes photons to Rydberg atomic ensembles, we show that the topological charge can be used to modulate photon-photon interactions. We demonstrate nonlocal single-photon switch and transistor with superior performance at high input photon numbers. Our nonlocal single-photon transistor, exploiting reduced self-blockade among OAM photons, achieves a high gain of 151-a threefold enhancement over the Gaussian-mode counterpart under similar experimental conditions. These results demonstrate robust nonlocal control over single photons in OAM modes, opening avenues for novel quantum devices and multiphoton quantum optics with Rydberg atoms.