An optical correlator automatically recognizes or identifies the contents of an image by combining an incoming image with a reference image, and the degree of correlation after combining the images determining the Intensity of an output Light beam.

Optical correlators can perform complex pattern recognition more rapidly than known Digital techniques. Optical correlators are capable of processing large amounts of Data in a data stream that can be useful in the detection, extraction and classification of desired information included in the data. Optical correlators are employed for many optical signal processing applications, including pattern and character recognition, implementation of optical interconnections in hybrid optoelectronic parallel computers, and in artificial neural Network technologies. Optical correlators are typically found in optical communication systems for signal detection applications involving data that are conveyed by light carriers whose Frequency or operating Wavelength is increasing as the technology continues to advance. The optical correlators are frequently implemented using spatial light Modulator (SLM) technology that involves spatial data serving as reference data and representative of two or three dimensional quantities commonly stored on holograms. Spatial light modulators (SLM) are transducers that modulate Incident Light in a spatial pattern corresponding to an electrical or optical input.