Slow-light all-optical transistors based on single-photon-level light storage.

We developed an effective theoretical method to examine the successive propagation dynamics of a gate field and a signal field in an EIT medium of Rydberg atoms exhibiting both self and cross van der Waals () interactions. It is found that the slow-light storage of this gate field can be achieved with an efficiency up to 73.5% and a negligible modification of photon statistics. More interestingly, even a single stored gate photon can effectively attenuate the otherwise low-loss signal field containing hundreds of photons during its slow-light transport by exploiting the cross interaction. Therefore, benefiting from a direct insight into the simulated propagation dynamics, we have demonstrated that a high-performance all-optical transistor is feasible with its optical gain (22) and contrast (0.999), two important figures of merit, both better than those reported in relevant experiments. More importantly, through the transistor process, we can obtain single photons that exhibit low biphoton correlation and a uniform distribution, distinct from the previous storage process.