Dynamically controlling the emission of single excitons in photonic crystal cavities.

Francesco Pagliano,Frank Van Otten,Tian Xia,Andrea Fiore,Yongjin Cho,Robert Johne

doi:10.1038/ncomms6786

Abstract

Single excitons in semiconductor microcavities represent a solid state and scalable platform for cavity quantum electrodynamics, potentially enabling an interface between flying (photon) and static (exciton) quantum bits in future quantum networks. While both single-photon emission and the strong coupling regime have been demonstrated, further progress has been hampered by the inability to control the coherent evolution of the cavity quantum electrodynamics system in real time, as needed to produce and harness charge–photon entanglement. Here using the ultrafast electrical tuning of the exciton energy in a photonic crystal diode, we demonstrate the dynamic control of the coupling of a single exciton to a photonic crystal cavity mode on a sub-nanosecond timescale, faster than the natural lifetime of the exciton. This opens the way to the control of single-photon waveforms, as needed for quantum interfaces, and to the real-time control of solid-state cavity quantum electrodynamics systems.

Highlights

Single excitons in semiconductor microcavities represent a solid state and scalable platform for cavity quantum electrodynamics, potentially enabling an interface between flying and static quantum bits in future quantum networks
In atomic cavity quantum electrodynamics (c-QED) system at microwave frequencies, this control is achieved by changing the interaction time[11], while at optical frequencies it is realized by adiabatic passage techniques, which enable shaping a photon waveform on 100-ns timescales[1,2,9,12]
While a number of approaches have been proposed for the control of the exciton–cavity interaction[21,22,23,24,25,26], none of them has been applied to control c-QED on the ultrafast timescales typical of solid-state systems

Summary

Introduction

Single excitons in semiconductor microcavities represent a solid state and scalable platform for cavity quantum electrodynamics, potentially enabling an interface between flying (photon) and static (exciton) quantum bits in future quantum networks. Using the ultrafast electrical tuning of the exciton energy in a photonic crystal diode, we demonstrate the dynamic control of the coupling of a single exciton to a photonic crystal cavity mode on a sub-nanosecond timescale, faster than the natural lifetime of the exciton This opens the way to the control of single-photon waveforms, as needed for quantum interfaces, and to the real-time control of solid-state cavity quantum electrodynamics systems. Semiconductor c-QED systems, for example, based on QDs in optical microcavities, present an evident potential in terms of integration and scalability While both single-photon emission[15,16] and the SC regime[5,6] have been demonstrated, the progress in their application to quantum information has been strongly limited by the absence of fast control methods, which would enable the generation of symmetric photons[17,18] as well as the implementation of quantum gates[19,20] and of entangled photon–exciton states. Further optimization of the structure will open the way to the control of SC c-QED systems

Methods

Results

Conclusion