Effects of SLM transmissive dead zones on optical correlation

The inactive areas of certain pixellated SLMs are transmissive rather than opaque, while their active areas modulate the optical phase or amplitude. Computer simulations of optical correlators are made for a continuous-input SLM and a filter SLM implementing either a classical matched, phase-only, or binary phase-only filter. The correlation peak and signal-to-noise ratio are studied as a function of dead-zone area in both the input and filter SLMs. These results are compared with those obtained from correlators whose SLMs have only opaque dead zones.