A substrate heating apparatus configured to be coupled to a processing system and radiatively heat a substrate is described. The substrate heating apparatus includes a radiative heat source coupled to a processing system and configured to produce electromagnetic (EM) radiation, a translucent object positioned between the radiative heat source and the substrate along a the EM radiation path, and an opaque object also positioned between the radiative heat source and the substrate along the EM radiation path. The translucent object includes at least one textured surface to cause random refraction of the EM radiation passing through the translucent object, or an optical waveguide configured to encapsulate the opaque object and direct the EM radiation around the opaque object, or both, to prevent creation of a shadow of the opaque object on the substrate.