  We generate silicon vacancy related defects in high-quality epitaxial silicon
carbide layers by means of electron irradiation. By controlling the irradiation
fluence, the defect concentration is varied over several orders of magnitude.
We establish the excitation profile for optical pumping of these defects and
evaluate the optimum excitation wavelength of 770 nm. We also measure the
photoluminescence dynamics at room temperature and find a monoexponential decay
with a characteristic lifetime of 6.1 ns. The integrated photoluminescence
intensity depends linear on the excitation power density up to 20 kW/cm$^2$,
indicating a relatively small absorption cross section of these defects.
