An illuminator , comprising: a first waveguide having a first planar face configured to illuminate an eye of a user of the illuminator and a second planar face opposite the first planar face; an infrared light source positioned to direct infrared radiation into the first waveguide; and a diffractive optical element on the first planar face of the first waveguide, said diffractive optical element configured for coupling light entering the waveguide from the source across the waveguide via total internal reflection and further coupling the infrared radiation out of at least the first planar face to create two or more virtual infrared light sources opposite the second planar face, wherein: the virtual infrared light sources comprises at least a first virtual infrared light source and a second virtual infrared light source, the first virtual infrared light source and the second virtual infrared light source are located at substantially different locations, said second planar face is provided with a coating reflective for infrared radiation, and the diffractive optical element comprises a first plurality of pixels corresponding to the first virtual infrared light source and further comprises a second plurality of pixels, different from the first plurality of pixels, corresponding to the second virtual infrared light source. a first waveguide having a first planar face configured to illuminate an eye of a user of the illuminator and a second planar face opposite the first planar face; an infrared light source positioned to direct infrared radiation into the first waveguide; and a diffractive optical element on the first planar face of the first waveguide, said diffractive optical element configured for coupling light entering the waveguide from the source across the waveguide via total internal reflection and further coupling the infrared radiation out of at least the first planar face to create two or more virtual infrared light sources opposite the second planar face, wherein: the virtual infrared light sources comprises at least a first virtual infrared light source and a second virtual infrared light source, the first virtual infrared light source and the second virtual infrared light source are located at substantially different locations, said second planar face is provided with a coating reflective for infrared radiation, and the diffractive optical element comprises a first plurality of pixels corresponding to the first virtual infrared light source and further comprises a second plurality of pixels, different from the first plurality of pixels, corresponding to the second virtual infrared light source. the virtual infrared light sources comprises at least a first virtual infrared light source and a second virtual infrared light source, the first virtual infrared light source and the second virtual infrared light source are located at substantially different locations, said second planar face is provided with a coating reflective for infrared radiation, and the diffractive optical element comprises a first plurality of pixels corresponding to the first virtual infrared light source and further comprises a second plurality of pixels, different from the first plurality of pixels, corresponding to the second virtual infrared light source. <EOS>