An apparatus including a set of three illumination sources disposed in a first plane. Each of the set of three illumination sources is disposed at a position in the first plane offset from others of the set of three illumination sources by 120 degrees measured in polar coordinates. The apparatus also includes a set of three waveguide layers disposed adjacent the set of three illumination sources. Each of the set of three waveguide layers includes an incoupling diffractive element disposed at a lateral position offset by 180 degrees from a corresponding illumination source of the set of three illumination sources.