We report systematic measurements of the lifetime of the 1.54 μm transition of erbium implanted at different energies in SiO2 films coated with titanium or chromium. The lifetime shows a strong reduction up to a factor of 20 with decreasing distance between the erbium and the metal coating. Our experiments combined with rigorous theoretical modeling demonstrate that a high degree of control over the radiative properties of erbium can be achieved in erbium-implanted materials.