The implementation of quantum networks and distributive quantum information processing relies on interaction between stationary matter qubits and flying photons1-6. The spin of a single electron or hole confined in a charged quantum dot is considered as a promising matter qubit as it possesses microsecond coherence time7,8 and allows picosecond timescale control using optical pulses9-12. The quantum dot spin can also interact with a photon by controlling the optical response of a strongly coupled cavity13-15. So far most experimental demonstrations of the cavity spectrum control have used neutral quantum dots16,17. Spin-dependent cavity spectrum has not been reported yet. Here, we report an experimental realization of a spin-photon transistor using a strongly coupled quantum dot and cavity system. We show large modulation of the cavity reflectivity by manipulating the spin states of the quantum dot. The spin-photon transistor is crucial for realizing a quantum logic gate or generating hybrid entanglement between a quantum dot spin and a photon18-21. Our results represent an important step towards semiconductor based quantum logic devices and on-chip quantum networks.
Edo Waks, Edo Waks,
"Controlling light with quantum dot spin on-a-chip", Proc. SPIE 10639, Micro- and Nanotechnology Sensors, Systems, and Applications X, 1063905 (8 May 2018); doi: 10.1117/12.2305568; https://doi.org/10.1117/12.2305568