Phase Only Liquid Crystal Light Modulator And Its Application In The Fourier Plane Of Optical Correlation Systems

It has been shown theoretically that optical correlation systems which use phase only filters are capable of producing sharp correlation peaks and good discrimination between different input objects, whilst at the same time having high optical efficiency. In addition to this, the resolution required in the filter plane is very much lower than that required for an equivalent conventional Van der Lugt correlator using a matched filter which has been made holographically. Here, we describe a flexible phase only filter implemented using a special-purpose liquid crystal spatial light modulator, and present results which demonstrate how it can be applied in optical correlation systems.