Theory of optical bistability in a weakly nonlinear composite medium

Abstract
A variational approach is used to discuss bistable behavior in composite media where one component is a nonlinear dielectric while the other has a field independent complex dielectric constant with a negative real part. Under certain conditions, the physical parameters may be adjusted so that bistability appears even though the nonlinear behavior is everywhere weak, thus allowing it to be treated as a small perturbation to the leading linear behavior.