  We demonstrate the control of the spontaneous emission rate of single InAs
quantum dots embedded in a double-membrane photonic crystal cavity by the
electromechanical tuning of the cavity resonance. Controlling the separation
between the two membranes with an electrostatic field we obtain the real-time
spectral alignment of the cavity mode to the excitonic line and we observe an
enhancement of the spontaneous emission rate at resonance. The cavity has been
tuned over 13 nm without shifting the exciton energies. A spontaneous emission
enhancement of 4.5 has been achieved with a coupling efficiency of the dot to
the mode 92%.
