This paper focuses on the deposition of silicon oxide thin films, using laser assisted CVD based on a CO_2 laser, and on the feasibility of the process for coating porous silicon samples. Scanning electron and atomic force microscopy were used to analyse the morphology and microstructure of the films, while structure and chemical composition were determined by Fourier transform infrared and Rutherford backscattering spectroscopy. Two-wavelength ellipsometry was used for thickness and refractive index evaluation. The photoluminescence of SiO_2/PS was measured and compared with tha of uncoated samples. direct c 1999 Elsevier Science B.V. All rights reserved.