We present and analyze pseudodielectric function data = + i of AlP from 0.75 to 5.05 eV. The sample is a 1.0 mu m thick AlP film grown on (001) GaAs by molecular beam epitaxy (MBE). Spectroscopic ellipsometric data were obtained before removing the sample from the MBE chamber to avoid oxidation and related artifacts. Analysis of interference oscillations and corrections for overlayer effects with a multilayer parametric model yield the closest representation to date of the intrinsic bulk dielectric response E of AlP. From this analysis we obtain the energies of the E(0)' and E(1) critical points of AlP. (C) 2011 Elsevier B.V. All rights reserved.