  A single-mode microcavity with an embedded Aharonov-Bohm quantum ring, which
is pierced by a magnetic flux and subjected to a lateral electric field, is
studied theoretically. It is shown that external electric and magnetic fields
provide additional means of control of the emission spectrum of the system. In
particular, when the magnetic flux through the quantum ring is equal to a
half-integer number of the magnetic flux quantum, a small change in the lateral
electric field allows tuning of the energy levels of the quantum ring into
resonance with the microcavity mode providing an efficient way to control the
quantum ring-microcavity coupling strength. Emission spectra of the system are
calculated for several combinations of the applied magnetic and electric
fields.
