Nonlinear background-to-signal coupling in lateral photoeffects

An analysis of the effect of a large spatially uniform time-independent background illumination on the lateral electric fields produced by a small space- and time-varying illumination of a junction is presented. It is shown that a nonlinear coupling between background and signal results in a decrease in the signal electric fields. A general solution is obtained, and a solution in terms of well-known functions for a physically interesting case is exhibited. The parameter dependences are discussed and the effect of finite conductivities in both regions is analyzed.