Dynamic acousto-optic control of a strongly coupled photonic molecule

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.

Strong Coupling in a Photonic Molecule Formed by Trapping a Microsphere in a Microtube Cavity

“…[3] In our work, instead of moving a tapered fiber on a spherical surface, we enabled coupling strength tuning by changing pump position along a line on the top of microtube, which is compatible for both farfield and nearfield means. Moreover, benchmarking with other studies on tuning the intercavity coupling strength of photonic molecules, our spa tially selective pumping scheme avoids the requirement of external techniques (e.g., an elastic substrate for strain engi neering [21,22] or an interdigital transducer for generating surface acoustic waves [23] ), and thus offer a simple and flexible way for regulating the mode coupling behaviors.…”

“…As such, one needs a deliberate control on both the cavity geometries and the intercavity coupling gap to ensure a good spectral match and efficient evanescent coupling between the coupled cavities. [18] Moreover, dynamic tuning of the intercavity coupling strength has been investigated in recent years, which were carried out by advanced and sophisticated techniques such as strain tuning, [21,22] acoustooptic control, [23] and precise micromanipulation techniques. [3] To extend and promote the research in the field of photonic molecules, it is of high interest to design novel photonic molecules extending from adjacent solid microcavities to thinwalled hollow cavities which possess intense evanescent field facilitating intercavity coupling and provide novel strategy for tuning of the coupling strength.…”

Surface acoustic wave modulation of a coherently driven quantum dot in a pillar microcavity

“…A sound wave excited on the surface of a piezoelectric semiconductor, and known as a surface acoustic wave (SAW), can change the separation of the energy levels in the dot as the lattice is stretched and compressed [14,15]. SAWs can be used for high frequency modulation at frequencies of MHz to tens of GHz [16][17][18][19]. Most reports on * bruno.villa@crl.toshiba.co.uk † Present address: Department of Electronic & Electrical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom SAW-modulated quantum structures to date are limited to samples without Purcell effect [20][21][22].…”

Surface acoustic wave regulated single photon emission from a coupled quantum dot–nanocavity system

“…In addition to light, these membrane structures guide [15] or confine vibronic excitations with strong optomechanical coupling strength [16,17]. These phononic modes can be directly employed to interface photonic crystal membranes by radio frequency surface acoustic waves (SAWs) [18,19]. As SAWs can be excited at GHz frequencies on piezoelectric materials [20,21], electrically induced and acoustically driven quantum gates are well within reach on this platform [22].…”