According to examples, an apparatus may include a back panel to absorb energy and an energy emitter to supply energy onto a build material layer. The energy emitter may include an energy emitting element and an outer tube. In addition, a reflective element may be provided on a portion of the outer tube facing the back panel to direct energy away from the back panel. The apparatus may also include a transparent panel, in which energy from the energy emitter may be emitted through the transparent panel and onto the build material layer.