Spectroscopic ellipsometry (SE) has been used to characterise damage depth profiles in silicon. The damage was produced by implantation of high energy ions of various atomic number with variable charge state and using various energies. The effect of substrate temperature was also investigated. In all cases a first characterisation was made using Rutherford backscattering experiments. Attempts were then made to extract accurate data from SE measurements. If the damage depth profile is thin ( < 200 nm), a simulation of SE in the range 0.25-0.82 μm using mixed materials and a simple or complex depth profile can give very accurate information. When the damage profile is thick enough (> 200 nm), an extended measurement in the near infrared (0.25-1.5 μm) gives direct information on the thickness of the damaged layer. In this latter case, data reduction is performed using Forouhi-Bloomer dispersion relations for the amorphized silicon layer.