Temporal filtering by double diffraction.

We present a theoretical analysis of the temporal behavior of double-diffraction setups. It applies, in particular, to Talbot and Montgomery interferometers, whose operation is based on the self-imaging effect. The use of both types of interferometer as temporal filters for optical and terahertz applications was recently suggested. We show that double-diffraction setups can be modeled as communications channels with dispersive behavior caused by diffraction. We develop mathematical expressions for the phase delay, the group velocity, and the group-velocity dispersion for both quasi-monochromatic and polychromatic case. Based on these results, the temporal impulse response of a double-diffraction setup is derived. Finally, a general description of its practical implementation are presented.