The reflectivity of single‐crystal and amorphous GaAs samples was measured in the photon energy range 1.5–7.0 eV. The amorphous specimens were obtained by 400‐keV Te implantation at room temperature. Some structures at high photon energy are still present in the imaginary part of the dielectric function for the Te‐implanted GaAs. The optical properties of such an amorphous layer differ noticeably from those reported in literature for flash‐evaporated films. The difference may be attributed to the lack of stoichiometry in the deposited layers.