Diffractive image display having hexagonal or diamond shaped phase modulating pixels

A method of providing a diffractive (holographic) image display comprises: displaying a diffraction pattern on pixels of a spatial light modulator (SLM), the SLM comprising a plurality of optical phase modulating pixels; and illuminating said SLM with a beam of light to reconstruct a far field image formed by said diffraction pattern, wherein the SLM pixels are hexagonal or diamond shaped. The pixels can have a shape parameter S of greater than 0.333, where S is dependent on a pixel pitch I x in a horizontal direction in a lateral plane of said SLM, a pixel pitch I y in a vertical direction in a lateral plane of said SLM, a length of dead space (gap) I DS between pixels, and a half H of a maximum dimension of a pixel in a lateral SLM plane measured in a vertical direction. The illumination beam may be at an angle to a SLM substrate normal, with a first diffraction order having a square shape. Pixels may include a phase step or ramp. Piston-type microelectromechanical system (MEMS) optical phase modulation pixels may be used.