Compared to the classical VanderLugt correlator, optical- hybrid frequency plane correlator systems are more flexible, but also more complicated. Implementation of the hybrid systems requires the use of addressable spatial light modulators to display contents of the input and filter planes and the use of the additional lenses to match the scalings in the system. Furthermore, hybrid systems use the optical elements such as quarter-wave plates, half-wave plates, and polarizers; which is all not needed for the classical setup. All these additional optical elements influence both amplitude and phase distortions of the wavefront that propagates throughout the system. For measuring the phase distortions of the optical elements, we have used the holographic setup with one mirror mounted on a piezo-electric transducer and controlled by a digital image processing system.
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