Information processing with spatially coherent light

Coherent light is the most popular carrier of a signal in an optical information processing system. The matched filtering system (Van Der Lugt 1965) is a prominent example. However, coherent optics is experimentally delicate, not well suited for unfriendly environments. As a reaction to this dilemma some new systems, that use totally incoherent light, have been presented recently. Those systems work reasonably well. But they can handle only real-valued non-negative signals, directly. An alternative approach is to use partially-coherent light. Now the optical system is not anymore as fragile as a coherent system. And the signals, which are now implemented as coherence functions, can be complex, in contrast to incoherent optics. However, the hardware of partially coherent systems is more elaborate.