Spatial frequency diversity in liquid crystal spatial light modulators applied to signal to noise ratio improvement in coherent opto-digital processors

Intrinsic properties of liquid crystals spatial light modulators (LCSLM), as sampling devices are commonly seen as disadvantage in opto-digital data processing; because the loss of light power due the replicated spectrum at the sampling process. We claim this apparent disadvantage can be seen as advantage if we consider to filter Q replicates of the Sampled image Fourier spectrum. Moreover, we can use this technique to improve the signal to noise ratio (S/N), or to develop several operations in parallel over the same input data. In this work we are interested in to improve the S/N in opto-digital image subtraction. Experimental results which reveal the advantage of this technique are shown.