  A major challenge for plasmonics as an enabling technology for quantum
information processing is the realization of active spatio-temporal control of
light on the nanoscale. The use of phase-shaped pulses or beams enforces
specific requirements for on-chip integration and imposes strict design
limitations. We introduce here an alternative approach, which is based on
exploiting the strong sub-wavelength spatial phase modulation in the near-field
of resonantly-excited high-Q optical microcavities integrated into plasmonic
nanocircuits. Our theoretical analysis reveals the formation of areas of
circulating powerflow (optical vortices) in the near-fields of optical
microcavities, whose positions and mutual coupling can be controlled by tuning
the microcavities parameters and the excitation wavelength. We show that
optical powerflow though nanoscale plasmonic structures can be dynamically
molded by engineering interactions of microcavity-induced optical vortices with
noble-metal nanoparticles. The proposed strategy of re-configuring plasmonic
nanocircuits via locally-addressable photonic elements opens the way to develop
chip-integrated optoplasmonic switching architectures, which is crucial for
implementation of quantum information nanocircuits.
