Pixellation of optically bistable elements

The elements of optical logic arrays can, in principle, be shielded from inter-element crosstalk by material pixellation. This confinement might seem to allow closer packing of such elements. However, using a Fourier optics approach to diffusion, we show that the pixellation process itself prevents radial removal of heat, and this can seriously affect device operation. The importance of this effect is illustrated by means of a numerical simulation.