Spectroscopic ellipsometry is a very useful non-destructive technique to characterise the thickness and composition of multilayers with a spatial resolution of 20 x 40 mum. The present way to map a sample is to scan the surface of the wafer with this spatial resolution. The new multiple wavelength ellipsometric imager discussed in this paper enables to acquire the full image with several wavelengths in a few seconds. First results obtained on standard SiO2/Si samples are described and the system performances in terms of accuracy, spatial resolution and signal over noise ratio are discussed. Effect of defects such as achromatism, anamorphose and boundary diffraction are characterised. (C) 2004 Elsevier B.V. All rights reserved.