Abstract
Thin film Fabry-Perot etalons which have a temperature dependent refractive index exhibit bistability or gain at room temperature (e.g. ZnSe) and at optical frequencies. These features make them candidates for digital optical computing. An N x N array of elements can be generated in a single filter by an array of laser beams. As a result, thermal crosstalk develops which is long range and only a few elements per cm2 on such a filter can operate independently [1,2]. However if each filter is mounted on its own separate 'turret', crosstalk can be reduced to the extent that 104 microcavities (or pixels) can operate independently per cm2 [3,4].