Modulation transfer function of extrinsic Si-detector arrays affected by optical crosstalk

It is shown in this paper that the imaging properties of crosstalk-affected silicon-detector arrays can be described by convolution of a line spread function (LSF) caused by detector width and of another one caused by crosstalk which is independent of detector width. For the Fourier transform of the latter LSF-the crosstalk MTF-there exists a simple analytic expression in the case of weak absorption: MTFC= Si (x)/x, Si being the sine integral. This is perfectly analogous to the MTF due to detector width: . That means that you have the effects of crosstalk in a form compatible with imaging theory and it is possible to incorporate them into performance calculations. Computation of the minimum resolvable temperature difference (MRTD) for a number of assumed systems shows that the limiting spatial frequency is not much affected, thermal sensitivity at intermediate frequencies, however, can be noticeably degraded. These effects can be offset by decreasing the width of the detectors and/or by increasing net thermal sensitivity.