The line spread function, crosstalk, and modulation transfer function (MTF) are computed for stripe geometries, assuming the absorption length is greater than the detector resolution element size. It is assumed that the radiation incident surface is antireflection coated and that the reflectivity of the exit face is a parameter. Numerical computations are carried out to find the optimal focal‐plane depth (least crosstalk), and the crosstalk is calculated at this optimal focal‐plane depth as a function of both absorption coefficient and detector width. The MTF is then calculated for various detector widths.