Fractional Talbot imaging set-up for high-efficiency real-time diffractive optics

An optical configuration based on the fractional Talbot effect is proposed to improve the diffraction efficiency of dynamic diffractive optical elements written on electronically addressed liquid crystal spatial light modulators with partially opaque pixels, or on any other spatial light modulator, where a part of the pixel area is inactive. Using diffractive cover plates, the high design efficiency of an ideal multilevel diffractive optical element can almost be achieved even if 3/4 of the pixel area is blocked by drive electronics; without such cover plates, the efficiency would be limited to 1/16 of the design efficiency.