a method and system for providing an improved color image wherein a broad spectrum light is supplied to a phase grating which provides dispersed light having multiple diffraction orders . the dispersed light is supplied to a zero - order phase shifter which shifts the phase of the undiffracted light relative to the diffracted light . the light from the phase shifter is thereupon concentrated so that the plane of the phase grating is imaged onto a display having a plurality of pixels assigned to transmit different spectral regions . the depths of the grating elements of each of the grating periods of the phase grating and the depth of the zero - order phase element of the phase shifter are selected to maximize the area of chromaticity space spanned by the different spectral regions at the display .