Hybrid joint transform correlator for optical security

The hybrid optical-digital two-stage joint transform correlator (JTC) experimental setup was created. The transformed phase mask (PM) was used as an optical mark to be identified in the hybrid JTC. The minimum possible focal length of a Fourier lens in the joint Fourier transform processor of the hybrid JTC first stage was defined and optical schemes were calculated and designed. The procedure of the transformed PM identification in the hybrid JTC was represented. Performance of transformed PMs in different modifications of the experimental setup was studied. The peak-to-noise ratio (PNR) for each correlation peak in the firs diffraction order of the output correlation signal was calculated. The dependencies PNR versus effective focal length were analyzed.