Ultrafast few-photon switching with a coherently driven quantum dot in the high Purcell factor regime

Author / Creator

Quantum 2020 (2020)

Conferences

Quantum 2020 P2: Quantum computing and quantum simulation (2020)

Available as

Online

Summary

Nonlinear optical interaction at a single photon level plays a key role in quantum optical information processing. One of its important applications is optical switching with extremely low power co...

Nonlinear optical interaction at a single photon level plays a key role in quantum optical information processing. One of its important applications is optical switching with extremely low power consumption. Although optical switching controlled by a few photons has been demonstrated using strongly coupled quantum dot-photonic crystal cavity systems, the strong coupling regime brings significant fabrication challenges as high cavity quality factor and accurate QD positioning are required. This becomes more problematic for integrated photonic circuits where the cavity Q-factor is strongly degraded due to the waveguide coupling. In this work, we show that low-photon number (~2 photons) optical switching can be realized with a QD weakly coupled to a low-Q (only 600) cavity in the high Purcell factor regime. Our scheme significantly relaxes the fabrication requirement while achieving high switching speed (22.7 ps), high switching contrast (39%), and large tunability. Our work paves the way towards the practical quantum optical switch, especially for on-chip photonic circuits.

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