Dynamic acousto-optic control of a strongly coupled photonic molecule.

Stephan Kapfinger,Thorsten Reichert,Jonathan J Finley,Kai Müller,Michael Kaniber,Achim Wixforth,Stefan Lichtmannecker,Hubert J Krenner

doi:10.1038/ncomms9540

Abstract

Strongly confined photonic modes can couple to quantum emitters and mechanical excitations. To harness the full potential in quantum photonic circuits, interactions between different constituents have to be precisely and dynamically controlled. Here, a prototypical coupled element, a photonic molecule defined in a photonic crystal membrane, is controlled by a radio frequency surface acoustic wave. The sound wave is tailored to deliberately switch on and off the bond of the photonic molecule on sub-nanosecond timescales. In time-resolved experiments, the acousto-optically controllable coupling is directly observed as clear anticrossings between the two nanophotonic modes. The coupling strength is determined directly from the experimental data. Both the time dependence of the tuning and the inter-cavity coupling strength are found to be in excellent agreement with numerical calculations. The demonstrated mechanical technique can be directly applied for dynamic quantum gate operations in state-of-the-art-coupled nanophotonic, quantum cavity electrodynamic and optomechanical systems.

Highlights

Confined photonic modes can couple to quantum emitters and mechanical excitations
The coherent phononic nature of surface acoustic wave (SAW) was verified by Metcalfe et al.[27] who demonstrated resolved sidebands in the emission of a SAW-driven quantum dot (QD) and performed optomechanical cooling and heating in this system
For the GaAs-based nanocavities, the cavity linewidth exceeds the sideband splitting set by oSAW

Summary

Introduction

Confined photonic modes can couple to quantum emitters and mechanical excitations. Towards large-scale quantum photonic networks[5,6], selective dynamic control of individual components and deterministic interactions between different constituents are of paramount importance[7] This calls for switching speeds on the system’s native timescales to enable Landau–Zener non-adiabatic control schemes[8,9]. SAWs have been used to dynamically control nanophotonic[18,19,20], plasmonic[21,22,23], integrated optical devices[24,25] and quantum dot (QD) emitters[26,27,28,29] at frequencies up to several GHz. The tuning range of our method is sufficiently large to compensate for the inherent fabrication-related cavity mode detuning and the operation speed exceeds that of typical[30] and downscaled[31] resonant mechanical approaches. Our results pave the way towards native mechanical control in these scaled on-chip optomechanical systems

Methods

Results

Conclusion