  Active, in situ control of light at the nanoscale remains a challenge in
modern physics and in nanophotonics in particular. A promising approach is to
take advantage of the technological maturity of nano-electromechanical systems
(NEMS) and to combine it with on-chip optics. However, in scaling down the
dimensions of such integrated devices, the coupling of a NEMS to optical fields
becomes challenging. Despite recent progress in nano-optomechanical coupling,
active control of optical fields at the nanoscale has not been achieved with an
on-chip NEMS thus far. Here, we show a new type of hybrid system, which
consists of an on-chip graphene NEMS suspended a few tens of nanometers above
nitrogen-vacancy centres (NVC), which are stable single photon emitters
embedded in nano-diamonds. Electromechanical control of the photons emitted by
the NVC is provided by electrostatic tuning of the graphene NEMS position,
which is transduced to a modulation of NVC emission intensity. The
optomechanical coupling between the graphene displacement and the NVC emission
is based on near-field dipole-dipole interaction. This class of optomechanical
coupling increases strongly for smaller distances, making it suitable for
devices with nanoscale dimensions. These achievements hold promise for the
selective control of single-emitter arrays on chip, optical spectroscopy of
individual nano-objects, integrated optomechanical information processing and
quantum optomechanics.
