Fractional pixel translations of Fresnel lenses written onto spatial light modulators

The focal point of a lens written onto a spatial light modulator can be translated laterally by displacement of the central location of the encoded lens function. We show that the beam can be translated by a fraction of a pixel, in contrast to the expected single-pixel limitation. This increases the positional sensitivity obtainable with this technique. Experimental results are presented. Key words: Fresnel lenses, diffractive optical elements, spatial light modulators, binary optical elements.