An in-situ broadband monitoring system was developed and integrated into a Leybold Syrus Pro 1100 deposition system equipped with an OMS4000 process spectrophotometer. The broadband monitor allows alternative recording of broadband spectra at the witness glass (transmission or reflection) or at the rotating substrate (transmission). First results on the deposition of metal island layers and gradient refractive index layers are presented. For reverse engineering of the refractive index profile a hybrid algorithm using recorded deposition rates is proposed. (c) 2005 Elsevier B.V. All rights reserved.