Optical logic operations via polarisation encoding in a phase conjugate Michelson interferometer

We demonstrate a technique of parallel optical logic operations performed on two two-dimensional input variables. The technique is based upon a cascaded phase conjugate Michelson interferometric (PCMI), arrangement, in which multiple signal beams, sharing a common reference beam, are used to record angularly multiplexed holograms in a single crystal of BSO. The logic operations are performed at the output port of a beamsplitter via polarization manipulation of the two phase conjugate outputs. When the PCMI is working in polarization preserving mode, complete subtraction is achieved. However, when the PCMI operates in non-polarization preserving mode, and the two phase conjugate beams are of nearly orthogonal polarizations to that of input polarizations, coherent addition is observed. By varying the polarization angle of the two phase conjugate outputs, continuous logic operations are achieved. We present the experimental results of all sixteen basic logic operations on two variables