Optical Bistability in Ag/Dielectric Multilayers

We numerically study the optical bistability (OBIS) in periodic multilayers of Ag/SiO₂. The calculated dependence of the output on the input intensity shows two possible OBIS states at the test wavelength. One is due to the field localization effects in silver layers with nonlinear refractive index modifying resonant tunneling of electromagnetic waves; the other, with about a three times lower threshold input intensity, is attributed to the intensity dependence change of the Ag/SiO₂ composite's effective dielectric constant from metallic−like (negative) to dielectric-like (positive). With appropriate design engineering the Ag/SiO₂ multilayers could find broad applications in all-optical information processes.