Detector noise limits the performance of signal-processing-in-the-elem
ent detectors. For detectors to be optimized, an expression for the si
gnal and noise must be found. The results of the eigenmode solution to
the charge transport problem are used to derive the power spectral de
nsity of the noise in analytic form. This result is then coordinated w
ith a similarly obtained modulation transfer function to yield a frequ
ency-dependent signal-to-noise ratio (SNR). The SNR is used to reveal
performance trends over several ranges of detector parameters. The mos
t important result is that the contact boundary velocity strongly cont
rols the SNR. The optimum SNR condition occurs when the contacts are n
ot perfectly ohmic but exhibit a partially blocking behavior. (C) 1996
Optical Society of America