A numerical integration method is presented for the classical anharmonic-os
cillator model describing the nonlinear response of a medium to an applied
optical field within the single-frequency approximation for self-action eff
ects. The formalism is applied to an analysis of the multistability of a Fa
bry-Perot resonator. The optical polarization P, rather than the optical E
field, is retained as the dynamical variable. We develop an algorithm for i
ntegration of the nonlinear wave equation in P and with addition of the non
linear boundary conditions at the resonator surfaces we are able to find th
e transmission as a function of intensity and frequency. The formalism appl
ies specifically to materials such as ferroelectrics with strong resonances
in the far-infrared spectral region. Illustrative graphs of transmission v
ersus incident intensity throughout the resonance region are presented. (C)
2001 Elsevier Science B.V. All rights reserved.