  We present an efficiently pumped single photon source based on single quantum
dots (QD) embedded in photonic crystal nanocavities. Resonant excitation of a
QD via a higher order cavity mode results in a 100$\times$ reduced optical
power at the saturation onset of the photoluminescence, compared with
excitation at the same frequency, after the cavity mode is detuned.
Furthermore, we demonstrate that this excitation scheme leads to selective
excitation of QDs coupled to the cavity by comparing photoluminescence and
auto-correlation spectra for the same excitation wavelength with and without
the cavity mode. This provides much cleaner conditions for single photon
generation.
