We realize an all-optical transistor where one stored gate photon controls the resonator transmission of several applied source photons. We also discuss experimental progress on generating entangled atomic ensembles using light.
The realization of an all-optical transistor, in which one "gate" photon controls a "source" light beam, is a long-standing goal in optics. By stopping a light pulse in an atomic ensemble contained inside an optical resonator, we realized a device in which one stored gate photon controls the resonator transmission of subsequently applied source photons. A weak gate pulse induces bimodal transmission distribution, corresponding to zero and one gate photons. One stored gate photon produces fivefold source attenuation and can be retrieved from the atomic ensemble after switching more than one source photon. Without retrieval, one stored gate photon can switch several hundred source photons. With improved storage and retrieval efficiency, our work may enable various new applications, including photonic quantum gates and deterministic multiphoton entanglement.
An all-optical transistor is a device in which a gate light pulse switches the transmission of a target light pulse with a gain above unity. The gain quantifies the change of the transmitted target photon number per incoming gate photon. We study the quantum limit of one incoming gate photon and observe a gain of 20. The gate pulse is stored as a Rydberg excitation in an ultracold gas. The transmission of the subsequent target pulse is suppressed by Rydberg blockade, which is enhanced by a Förster resonance. The detected target photons reveal in a single shot with a fidelity above 0.86 whether a Rydberg excitation was created during the gate pulse. The gain offers the possibility to distribute the transistor output to the inputs of many transistors, thus making complex computational tasks possible.
An all-optical transistor is a device in which a gate light pulse switches the transmission of a target light pulse with a gain above unity.The gain quantifies the change of the transmitted target photon number per incoming gate photon.We study the quantum limit of one incoming gate photon and observe a gain of 20.The gate pulse is stored as a Rydberg excitation in an ultracold gas.The transmission of the subsequent target pulse is suppressed by Rydberg blockade, which is enhanced by a Förster resonance.The detected target photons reveal in a single shot with a fidelity above 0.86 whether a Rydberg excitation was created during the gate pulse.The gain offers the possibility to distribute the transistor output to the inputs of many transistors, thus making complex computational tasks possible.
Quantum Optics
A long-standing goal in optics is to produce a solid-state alloptical transistor, in which the transmission of light can be controlled by a single photon that acts as a gate or switch. Sun et al. used a solid-state system comprising a quantum dot embedded in a photonic crystal cavity to show that transmission through the cavity can be controlled with a single photon. The single photon is used to manipulate the occupation of electronic energy levels within the quantum dot, which in turn changes its optical properties. With the gate open, about 28 photons can get through the cavity on average, thus demonstrating single-photon switching and the gain for an optical transistor.
Science , this issue p. [57][1]
[1]: /lookup/doi/10.1126/science.aat3581