Quadratically nonlinear systems may be analyzed and synthesized by linear methods by exchanging an <i>N</i>-dimensional nonlinear problem for a 2<i>N</i>-dimensional linear formulation. This paper describes the basis for such linearization of a quadratic functional, and applies the method to partially coherent transilluminated optical systems.
© 1969 Optical Society of America
R. KEITH RANEY, "Quadratic Filter Theory and Partially Coherent Optical Systems," J. Opt. Soc. Am. 59, 1149-1152 (1969)